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Grassmann G, Miotto M, Desantis F, Di Rienzo L, Tartaglia GG, Pastore A, Ruocco G, Monti M, Milanetti E. Computational Approaches to Predict Protein-Protein Interactions in Crowded Cellular Environments. Chem Rev 2024; 124:3932-3977. [PMID: 38535831 PMCID: PMC11009965 DOI: 10.1021/acs.chemrev.3c00550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 04/11/2024]
Abstract
Investigating protein-protein interactions is crucial for understanding cellular biological processes because proteins often function within molecular complexes rather than in isolation. While experimental and computational methods have provided valuable insights into these interactions, they often overlook a critical factor: the crowded cellular environment. This environment significantly impacts protein behavior, including structural stability, diffusion, and ultimately the nature of binding. In this review, we discuss theoretical and computational approaches that allow the modeling of biological systems to guide and complement experiments and can thus significantly advance the investigation, and possibly the predictions, of protein-protein interactions in the crowded environment of cell cytoplasm. We explore topics such as statistical mechanics for lattice simulations, hydrodynamic interactions, diffusion processes in high-viscosity environments, and several methods based on molecular dynamics simulations. By synergistically leveraging methods from biophysics and computational biology, we review the state of the art of computational methods to study the impact of molecular crowding on protein-protein interactions and discuss its potential revolutionizing effects on the characterization of the human interactome.
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Affiliation(s)
- Greta Grassmann
- Department
of Biochemical Sciences “Alessandro Rossi Fanelli”, Sapienza University of Rome, Rome 00185, Italy
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Mattia Miotto
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Fausta Desantis
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- The
Open University Affiliated Research Centre at Istituto Italiano di
Tecnologia, Genoa 16163, Italy
| | - Lorenzo Di Rienzo
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Gian Gaetano Tartaglia
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
- Center
for Human Technologies, Genoa 16152, Italy
| | - Annalisa Pastore
- Experiment
Division, European Synchrotron Radiation
Facility, Grenoble 38043, France
| | - Giancarlo Ruocco
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
| | - Michele Monti
- RNA
System Biology Lab, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Edoardo Milanetti
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
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2
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Guillaumin S, Gurdal M, Zeugolis DI. Gums as Macromolecular Crowding Agents in Human Skin Fibroblast Cultures. Life (Basel) 2024; 14:435. [PMID: 38672707 PMCID: PMC11051389 DOI: 10.3390/life14040435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/10/2024] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Even though tissue-engineered medicines are under intense academic, clinical, and commercial investigation, only a handful of products have been commercialised, primarily due to the costs associated with their prolonged manufacturing. While macromolecular crowding has been shown to enhance and accelerate extracellular matrix deposition in eukaryotic cell culture, possibly offering a solution in this procrastinating tissue-engineered medicine development, there is still no widely accepted macromolecular crowding agent. With these in mind, we herein assessed the potential of gum Arabic, gum gellan, gum karaya, and gum xanthan as macromolecular crowding agents in WS1 skin fibroblast cultures (no macromolecular crowding and carrageenan were used as a control). Dynamic light scattering analysis revealed that all macromolecules had negative charge and were polydispersed. None of the macromolecules affected basic cellular function. At day 7 (the longest time point assessed), gel electrophoresis analysis revealed that all macromolecules significantly increased collagen type I deposition in comparison to the non-macromolecular crowding group. Also at day 7, immunofluorescence analysis revealed that carrageenan; the 50 µg/mL, 75 µg/mL, and 100 µg/mL gum gellan; and the 500 µg/mL and 1000 µg/mL gum xanthan significantly increased both collagen type I and collagen type III deposition and only carrageenan significantly increased collagen type V deposition, all in comparison to the non-macromolecular crowding group at the respective time point. This preliminary study demonstrates the potential of gums as macromolecular crowding agents, but more detailed biological studies are needed to fully exploit their potential in the development of tissue-engineered medicines.
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Affiliation(s)
- Salome Guillaumin
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL) and Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, University of Galway, H91 TK33 Galway, Ireland; (S.G.); (M.G.)
| | - Mehmet Gurdal
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL) and Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, University of Galway, H91 TK33 Galway, Ireland; (S.G.); (M.G.)
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Charles Institute of Dermatology, Conway Institute of Biomolecular & Biomedical Research and School of Mechanical & Materials Engineering, University College Dublin (UCD), D04 V1W8 Dublin, Ireland
| | - Dimitrios I. Zeugolis
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL) and Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, University of Galway, H91 TK33 Galway, Ireland; (S.G.); (M.G.)
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Charles Institute of Dermatology, Conway Institute of Biomolecular & Biomedical Research and School of Mechanical & Materials Engineering, University College Dublin (UCD), D04 V1W8 Dublin, Ireland
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3
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Singh BP, Cheppali SK, Saha I, Swamy MJ. Contrasting effects of molecular crowding on the membrane-perturbing and chaperone-like activities of major bovine seminal plasma protein, PDC-109. Int J Biol Macromol 2024; 254:127573. [PMID: 37923045 DOI: 10.1016/j.ijbiomac.2023.127573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 11/07/2023]
Abstract
Crowded environments inside cells and biological fluids greatly affect protein stability and activity. PDC-109, a polydisperse oligomeric protein of the bovine seminal plasma selectively binds choline phospholipids on the sperm cell surface and causes membrane destabilization and lipid efflux, leading to acrosome reaction. PDC-109 also exhibits chaperone-like activity (CLA) and protects client proteins against various kinds of stress, such as high temperature and low pH. In the present work, we have investigated the effect of molecular crowding on these two different activities of PDC-109 employing Dextran 70 (D70) - a widely used polymeric dextran - as the crowding agent. The results obtained show that presence of D70 markedly increases membrane destabilization by PDC-109. Isothermal titration calorimetric studies revealed that under crowded condition the binding affinity of PDC-109 for choline phospholipids increases approximately 3-fold, which could in turn facilitate membrane destabilization. In contrast, under identical conditions, its CLA was reduced significantly. The decreased CLA could be correlated to reduced surface hydrophobicity, which was due to stabilization of the protein oligomers. These results establish that molecular crowding exhibits contrasting effects on two different functional activities of PDC-109 and highlight the importance of microenvironment of proteins in modulating their functional activities.
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Affiliation(s)
| | | | - Ishita Saha
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, India
| | - Musti J Swamy
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
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4
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Posey AE, Ross KA, Bagheri M, Lanum EN, Khan MA, Jennings CE, Harwig MC, Kennedy NW, Hilser VJ, Harden JL, Hill RB. The variable domain from dynamin-related protein 1 promotes liquid-liquid phase separation that enhances its interaction with cardiolipin-containing membranes. Protein Sci 2023; 32:e4787. [PMID: 37743569 PMCID: PMC10578129 DOI: 10.1002/pro.4787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
Dynamins are an essential superfamily of mechanoenzymes that remodel membranes and often contain a "variable domain" important for regulation. For the mitochondrial fission dynamin, dynamin-related protein 1, a regulatory role for the variable domain (VD) is demonstrated by gain- and loss-of-function mutations, yet the basis for this is unclear. Here, the isolated VD is shown to be intrinsically disordered and undergo a cooperative transition in the stabilizing osmolyte trimethylamine N-oxide. However, the osmolyte-induced state is not folded and surprisingly appears as a condensed state. Other co-solutes including known molecular crowder Ficoll PM 70, also induce a condensed state. Fluorescence recovery after photobleaching experiments reveal this state to be liquid-like indicating the VD undergoes a liquid-liquid phase separation under crowding conditions. These crowding conditions also enhance binding to cardiolipin, a mitochondrial lipid, which appears to promote phase separation. Since dynamin-related protein 1 is found assembled into discrete punctate structures on the mitochondrial surface, the inference from the present work is that these structures might arise from a condensed state involving the VD that may enable rapid tuning of mechanoenzyme assembly necessary for fission.
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Affiliation(s)
- Ammon E. Posey
- Program in Molecular BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
- Present address:
Department of Biomedical EngineeringWashington UniversitySt. LouisMissouriUSA
| | - Kyle A. Ross
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Mehran Bagheri
- Department of PhysicsUniversity of OttawaOttawaOntarioUSA
| | - Elizabeth N. Lanum
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Misha A. Khan
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
| | | | - Megan C. Harwig
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Nolan W. Kennedy
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Vincent J. Hilser
- Program in Molecular BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
| | | | - R. Blake Hill
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsinUSA
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5
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Ali M, Lee Y, Ha B, Jung J, Lee BY, Kim DS, Lee MY, Kim YS. The bone-protective benefits of amino-conjugated calcium in an ovariectomized (OVX) rat model. Life Sci 2023; 328:121927. [PMID: 37437650 DOI: 10.1016/j.lfs.2023.121927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/03/2023] [Accepted: 07/07/2023] [Indexed: 07/14/2023]
Abstract
Low bone density, fragility, and microarchitectural disintegration are the symptoms of osteoporosis. An imbalance between bone growth and resorption can lead to osteoporosis. This study evaluated the effects of amino-calcium (AC) on bone protection in ovariectomized control group (NC) rats. Amino-calcium (AC) was characterized using Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and nuclear magnetic resonance spectroscopy analyses (NMR). After determining the biocompatibility of amino-calcium (AC) with MC3T3-E1 cells, alkaline phosphatase staining revealed significant changes on day 7. Three of the four groups underwent ovariectomy, whereas one group received a placebo. On micro-computed tomography, in vivo, data showed increased bone volume fraction in the femoral head and shaft areas in the amino-calcium (AC) group. Hematoxylin and eosin staining showed a bone mass and architectural protection in the amino-calcium (AC) group compared with the calcium carbonate and OVX control group. RNA sequencing analysis revealed high expression of osteogenesis-related genes in MC3T3-E1 cells. RNA sequencing revealed a significant fold change in the expression of integrin-binding sialoprotein (IBSP), bone gamma-carboxyglutamate proteins 1 and 2(BGLAP1 and BGLAP2), and periostin (POSTN). The study concluded that supplementing the OVX rats with calcium enhanced bone protection.
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Affiliation(s)
- Maqsood Ali
- Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea; Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea
| | - Youri Lee
- Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea; Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea
| | - Bin Ha
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, Asan, Chungnam 31538, Republic of Korea; Department of Medical Biotechnology, College of Medical Sciences, Soonchunhyang University, Asan, Chungnam 31538, Republic of Korea
| | - Jaeeun Jung
- Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Byung-Yeol Lee
- Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea; BTN Co., Ltd., 407ho, Entrepreneurship Hall, 22 Soonchunhyang-ro, Asan, Chungnam 31538, Republic of Korea
| | - Dae-Soo Kim
- Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Mi-Young Lee
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, Asan, Chungnam 31538, Republic of Korea; Department of Medical Biotechnology, College of Medical Sciences, Soonchunhyang University, Asan, Chungnam 31538, Republic of Korea
| | - Yong-Sik Kim
- Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea; Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan, Chungnam 31151, Republic of Korea.
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6
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Posey AE, Bagheri M, Ross KA, Lanum EN, Khan MA, Jennings CM, Harwig MC, Kennedy NW, Hilser VJ, Harden JL, Hill RB. The variable domain from the mitochondrial fission mechanoenzyme Drp1 promotes liquid-liquid phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.29.542732. [PMID: 37398258 PMCID: PMC10312466 DOI: 10.1101/2023.05.29.542732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Dynamins are an essential superfamily of mechanoenzymes that remodel membranes and often contain a "variable domain" (VD) important for regulation. For the mitochondrial fission dynamin, Drp1, a regulatory role for the VD is demonstrated by mutations that can elongate, or fragment, mitochondria. How the VD encodes inhibitory and stimulatory activity is unclear. Here, isolated VD is shown to be intrinsically disordered (ID) yet undergoes a cooperative transition in the stabilizing osmolyte TMAO. However, the TMAO stabilized state is not folded and surprisingly appears as a condensed state. Other co-solutes including known molecular crowder Ficoll PM 70, also induce a condensed state. Fluorescence recovery after photobleaching experiments reveal this state to be liquid-like indicating the VD undergoes a liquid-liquid phase separation under crowding conditions. These crowding conditions also enhance binding to cardiolipin, a mitochondrial lipid, raising the possibility that phase separation may enable rapid tuning of Drp1 assembly necessary for fission.
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7
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Delgado A, Vera-Villalobos J, Paz JL, Lossada C, Hurtado-León ML, Marrero-Ponce Y, Toro-Mendoza J, Alvarado YJ, González-Paz L. Macromolecular crowding impact on anti-CRISPR AcrIIC3/NmeCas9 complex: Insights from scaled particle theory, molecular dynamics, and elastic networks models. Int J Biol Macromol 2023:125113. [PMID: 37257544 DOI: 10.1016/j.ijbiomac.2023.125113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/02/2023]
Abstract
The coupling of Cas9 and its inhibitor AcrIIC3, both from the bacterium Neisseria meningitidis (Nme), form a homodimer of the (NmeCas9/AcrIIC3)2 type. This coupling was studied to assess the impact of their interaction with the crowders in the following environments: (1) homogeneous crowded, (2) heterogeneous, and (3) microheterogeneous cytoplasmic. For this, statistical thermodynamic models based on the scaled particle theory (SPT) were used, considering the attractive and repulsive protein-crowders contributions and the stability of the formation of spherocylindrical homodimers and the effects of changes in the size of spherical dimers were estimated. Studies based on models of dynamics, elastic networks, and statistical potentials to the formation of complexes NmeCas9/AcrIIC3 using PEG as the crowding agent support the predictions from SPT. Macromolecular crowding stabilizes the formation of the dimers, being more significant when the attractive protein-crowder interactions are weaker and the crowders are smaller. The coupling is favored towards the formation of spherical and compact dimers due to crowding addition (excluded-volume effects) and the thermodynamic stability of the dimers is markedly dependent on the size of the crowders. These results support the experimental mechanistic proposal of inhibition of NmeCas9 mediated by AcrIIC3.
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Affiliation(s)
- Ariana Delgado
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Biomedicina Molecular (CBM), Laboratorio de Química Biofísica Teórica y Experimental (LQBTE), 4001 Maracaibo, Zulia, Venezuela; Universidad del Zulia (LUZ), Facultad Experimental de Ciencias (FEC), Departamento de Química, Laboratorio de Química Teórica y Computacional (LQTC), 4001 Maracaibo, Venezuela
| | - Joan Vera-Villalobos
- Facultad de Ciencias Naturales y Matemáticas, Departamento de Química y Ciencias Ambientales, Laboratorio de Análisis Químico Instrumental (LAQUINS), Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
| | - José Luis Paz
- Departamento Académico de Química Inorgánica, Facultad de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Carla Lossada
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Biomedicina Molecular (CBM), Laboratorio de Biocomputación (LB), 4001 Maracaibo, Zulia, Venezuela
| | - María Laura Hurtado-León
- Universidad del Zulia (LUZ), Facultad Experimental de Ciencias (FEC), Departamento de Biología, Laboratorio de Genética y Biología Molecular (LGBM), 4001 Maracaibo, Venezuela
| | - Yovani Marrero-Ponce
- Universidad San Francisco de Quito (USFQ), Grupo de Medicina Molecular y Traslacional (MeM&T), Colegio de Ciencias de la Salud (COCSA), Escuela de Medicina, Edificio de Especialidades Médicas, Quito 170157, Pichincha, Ecuador; Departamento de Ciencias de la Computación, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Baja California 22860, Mexico; Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y vía Interoceánica, Quito 170157, Pichincha, Ecuador
| | - Jhoan Toro-Mendoza
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Biomedicina Molecular (CBM), Laboratorio de Química Biofísica Teórica y Experimental (LQBTE), 4001 Maracaibo, Zulia, Venezuela
| | - Ysaías J Alvarado
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Biomedicina Molecular (CBM), Laboratorio de Química Biofísica Teórica y Experimental (LQBTE), 4001 Maracaibo, Zulia, Venezuela.
| | - Lenin González-Paz
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Biomedicina Molecular (CBM), Laboratorio de Biocomputación (LB), 4001 Maracaibo, Zulia, Venezuela.
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8
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Sung HL, Nesbitt DJ. Synergism in the Molecular Crowding of Ligand-Induced Riboswitch Folding: Kinetic/Thermodynamic Insights from Single-Molecule Spectroscopy. J Phys Chem B 2022; 126:6419-6427. [PMID: 35981263 DOI: 10.1021/acs.jpcb.2c03507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Conformational dynamics in riboswitches involves ligand binding and folding of RNA, each of which can be influenced by excluded volume effects under "crowded" in vivo cellular conditions and thus incompletely characterized by in vitro studies under dilute buffer conditions. In this work, temperature-dependent single-molecule fluorescence resonance energy transfer (FRET) spectroscopy is used to characterize the thermodynamics of (i) cognate ligand and (ii) molecular crowders (PEG, polyethylene glycol) on folding of the B. subtilis LysC lysine riboswitch. With the help of detailed kinetic analysis, we isolate and study the effects of PEG on lysine binding and riboswitch folding steps individually, from which we find that PEG crowding facilitates riboswitch folding primarily via a surprising increase in affinity for the cognate ligand. This is furthermore confirmed by temperature-dependent studies, which reveal that PEG crowding is not purely entropic and instead significantly impacts both enthalpic and entropic contributions to the free energy landscape for folding. The results indicate that PEG molecular crowding/stabilization of the lysine riboswitch is more mechanistically complex and requires extension beyond the conventional picture of purely repulsive solvent-solute steric interactions arising from excluded volume and entropy. Instead, the current experimental FRET data support an alternative multistep mechanism, whereby PEG first entropically crowds the unfolded riboswitch into a "pre-folded" conformation, which in turn greatly increases the ligand binding affinity and thereby enhances the overall equilibrium for riboswitch folding.
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Affiliation(s)
- Hsuan-Lei Sung
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, United States.,Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - David J Nesbitt
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, United States.,Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States.,Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
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9
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Rivas G, Minton A. Influence of Nonspecific Interactions on Protein Associations: Implications for Biochemistry In Vivo. Annu Rev Biochem 2022; 91:321-351. [PMID: 35287477 DOI: 10.1146/annurev-biochem-040320-104151] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cellular interior is composed of a variety of microenvironments defined by distinct local compositions and composition-dependent intermolecular interactions. We review the various types of nonspecific interactions between proteins and between proteins and other macromolecules and supramolecular structures that influence the state of association and functional properties of a given protein existing within a particular microenvironment at a particular point in time. The present state of knowledge is summarized, and suggestions for fruitful directions of research are offered. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Germán Rivas
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Madrid, Spain;
| | - Allen Minton
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA;
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10
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Speer SL, Stewart CJ, Sapir L, Harries D, Pielak GJ. Macromolecular Crowding Is More than Hard-Core Repulsions. Annu Rev Biophys 2022; 51:267-300. [PMID: 35239418 DOI: 10.1146/annurev-biophys-091321-071829] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells are crowded, but proteins are almost always studied in dilute aqueous buffer. We review the experimental evidence that crowding affects the equilibrium thermodynamics of protein stability and protein association and discuss the theories employed to explain these observations. In doing so, we highlight differences between synthetic polymers and biologically relevant crowders. Theories based on hard-core interactions predict only crowding-induced entropic stabilization. However, experiment-based efforts conducted under physiologically relevant conditions show that crowding can destabilize proteins and their complexes. Furthermore, quantification of the temperature dependence of crowding effects produced by both large and small cosolutes, including osmolytes, sugars, synthetic polymers, and proteins, reveals enthalpic effects that stabilize or destabilize proteins. Crowding-induced destabilization and the enthalpic component point to the role of chemical interactions between and among the macromolecules, cosolutes, and water. We conclude with suggestions for future studies. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Shannon L Speer
- Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina, USA;
| | - Claire J Stewart
- Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina, USA;
| | - Liel Sapir
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Daniel Harries
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem, Israel
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina, USA; .,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, North Carolina, USA.,Lineberger Cancer Research Center, University of North Carolina at Chapel Hill, North Carolina, USA
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11
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Dong X, Qin LY, Gong Z, Qin S, Zhou HX, Tang C. Preferential Interactions of a Crowder Protein with the Specific Binding Site of a Native Protein Complex. J Phys Chem Lett 2022; 13:792-800. [PMID: 35044179 PMCID: PMC8852806 DOI: 10.1021/acs.jpclett.1c03794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonspecific binding of crowder proteins with functional proteins is likely prevalent in vivo, yet direct quantitative evidence, let alone residue-specific information, is scarce. Here we present nuclear magnetic resonance (NMR) characterization showing that bovine serum albumin weakly but preferentially interacts with the histidine carrier protein (HPr). Notably, the binding interface overlaps with that for HPr's specific partner protein, EIN, leading to competition. The crowder protein thus decreases the EIN-HPr binding affinity and accelerates the dissociation of the native complex. In contrast, Ficoll-70 stabilizes the native complex and slows its dissociation, as one would expect from excluded-volume and microviscosity effects. Our atomistic modeling of macromolecular crowding rationalizes the experimental data and provides quantitative insights into the energetics of protein-crowder interactions. The integrated NMR and modeling study yields benchmarks for the effects of crowded cellular environments on protein-protein specific interactions, with implications for evolution regarding how nonspecific binding can be minimized or exploited.
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Affiliation(s)
- Xu Dong
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance at Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
| | - Ling-Yun Qin
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance at Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhou Gong
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance at Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
| | - Sanbo Qin
- Department of Chemistry and Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, United States
| | - Huan-Xiang Zhou
- Department of Chemistry and Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Chun Tang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
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12
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Kim R, Radhakrishnan ML. Macromolecular crowding effects on electrostatic binding affinity: Fundamental insights from theoretical, idealized models. J Chem Phys 2021; 154:225101. [PMID: 34241219 DOI: 10.1063/5.0042082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The crowded cellular environment can affect biomolecular binding energetics, with specific effects depending on the properties of the binding partners and the local environment. Often, crowding effects on binding are studied on particular complexes, which provide system-specific insights but may not provide comprehensive trends or a generalized framework to better understand how crowding affects energetics involved in molecular recognition. Here, we use theoretical, idealized molecules whose physical properties can be systematically varied along with samplings of crowder placements to understand how electrostatic binding energetics are altered through crowding and how these effects depend on the charge distribution, shape, and size of the binding partners or crowders. We focus on electrostatic binding energetics using a continuum electrostatic framework to understand effects due to depletion of a polar, aqueous solvent in a crowded environment. We find that crowding effects can depend predictably on a system's charge distribution, with coupling between the crowder size and the geometry of the partners' binding interface in determining crowder effects. We also explore the effect of crowder charge on binding interactions as a function of the monopoles of the system components. Finally, we find that modeling crowding via a lowered solvent dielectric constant cannot account for certain electrostatic crowding effects due to the finite size, shape, or placement of system components. This study, which comprehensively examines solvent depletion effects due to crowding, complements work focusing on other crowding aspects to help build a holistic understanding of environmental impacts on molecular recognition.
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Affiliation(s)
- Rachel Kim
- Department of Chemistry, Wellesley College, Wellesley, Massachusetts 02481, USA
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13
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Jang S, Schaich MA, Khuu C, Schnable BL, Majumdar C, Watkins SC, David SS, Van Houten B. Single molecule analysis indicates stimulation of MUTYH by UV-DDB through enzyme turnover. Nucleic Acids Res 2021; 49:8177-8188. [PMID: 34232996 PMCID: PMC8373069 DOI: 10.1093/nar/gkab591] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 06/09/2021] [Accepted: 06/24/2021] [Indexed: 11/30/2022] Open
Abstract
The oxidative base damage, 8-oxo-7,8-dihydroguanine (8-oxoG) is a highly mutagenic lesion because replicative DNA polymerases insert adenine (A) opposite 8-oxoG. In mammalian cells, the removal of A incorporated across from 8-oxoG is mediated by the glycosylase MUTYH during base excision repair (BER). After A excision, MUTYH binds avidly to the abasic site and is thus product inhibited. We have previously reported that UV-DDB plays a non-canonical role in BER during the removal of 8-oxoG by 8-oxoG glycosylase, OGG1 and presented preliminary data that UV-DDB can also increase MUTYH activity. In this present study we examine the mechanism of how UV-DDB stimulates MUTYH. Bulk kinetic assays show that UV-DDB can stimulate the turnover rate of MUTYH excision of A across from 8-oxoG by 4-5-fold. Electrophoretic mobility shift assays and atomic force microscopy suggest transient complex formation between MUTYH and UV-DDB, which displaces MUTYH from abasic sites. Using single molecule fluorescence analysis of MUTYH bound to abasic sites, we show that UV-DDB interacts directly with MUTYH and increases the mobility and dissociation rate of MUTYH. UV-DDB decreases MUTYH half-life on abasic sites in DNA from 8800 to 590 seconds. Together these data suggest that UV-DDB facilitates productive turnover of MUTYH at abasic sites during 8-oxoG:A repair.
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Affiliation(s)
- Sunbok Jang
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Matthew A Schaich
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Cindy Khuu
- Department of Chemistry and Biochemistry, Molecular, Cell and Development Graduate Group, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Brittani L Schnable
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburg, PA 15260, USA
| | - Chandrima Majumdar
- Department of Chemistry and Biochemistry, Molecular, Cell and Development Graduate Group, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Simon C Watkins
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sheila S David
- Department of Chemistry and Biochemistry, Molecular, Cell and Development Graduate Group, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Bennett Van Houten
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburg, PA 15260, USA
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14
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Molecular crystallization directed by polymer size and overlap under dilute and crowded macromolecular conditions. Polym J 2021. [DOI: 10.1038/s41428-021-00461-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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15
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Stadmiller SS, Pielak GJ. Protein-complex stability in cells and in vitro under crowded conditions. Curr Opin Struct Biol 2020; 66:183-192. [PMID: 33285342 DOI: 10.1016/j.sbi.2020.10.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/19/2020] [Accepted: 10/24/2020] [Indexed: 11/29/2022]
Abstract
Biology is beginning to appreciate the effects of the crowded and complex intracellular environment on the equilibrium thermodynamics and kinetics of protein folding. The next logical step involves the interactions between proteins. We review quantitative, wet-experiment based efforts aimed at understanding how and why high concentrations of small molecules, synthetic polymers, biologically relevant cosolutes and the interior of living cells affect the energetics of protein-protein interactions. We then address popular theories used to explain the effects and suggest expeditious paths for a more methodical integration of experiment and simulation.
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Affiliation(s)
- Samantha S Stadmiller
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-3290, USA
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-3290, USA; Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA.
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16
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Stadmiller SS, Aguilar JS, Parnham S, Pielak GJ. Protein–Peptide Binding Energetics under Crowded Conditions. J Phys Chem B 2020; 124:9297-9309. [DOI: 10.1021/acs.jpcb.0c05578] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Samantha S. Stadmiller
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Jhoan S. Aguilar
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Stuart Parnham
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Gary J. Pielak
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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17
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De Pieri A, Rana S, Korntner S, Zeugolis DI. Seaweed polysaccharides as macromolecular crowding agents. Int J Biol Macromol 2020; 164:434-446. [PMID: 32679331 DOI: 10.1016/j.ijbiomac.2020.07.087] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
Development of mesenchymal stem cell-based tissue engineered implantable devices requires prolonged in vitro culture for the development of a three-dimensional implantable device, which leads to phenotypic drift, thus hindering the clinical translation and commercialisation of such approaches. Macromolecular crowding, a biophysical phenomenon based on the principles of excluded-volume effect, dramatically accelerates and increases extracellular matrix deposition during in vitro culture. However, the optimal macromolecular crowder is still elusive. Herein, we evaluated the biophysical properties of various concentrations of different seaweed in origin sulphated polysaccharides and their effect on human adipose derived stem cell cultures. Carrageenan, possibly due to its high sulphation degree, exhibited the highest negative charge values. No correlation was observed between the different concentrations of the crowders and charge, polydispersity index, hydrodynamic radius and fraction volume occupancy across all crowders. None of the crowders, but arabinogalactan, negatively affected cell viability. Carrageenan, fucoidan, galactofucan and ulvan increased extracellular matrix (especially collagen type I and collagen type V) deposition. Carrageenan induced the highest osteogenic effect and galactofucan and fucoidan demonstrated the highest chondrogenic effect. All crowders were relatively ineffective with respect to adipogenesis. Our data highlight the potential of sulphated seaweed polysaccharides for tissue engineering purposes.
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Affiliation(s)
- Andrea De Pieri
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland; Proxy Biomedical Ltd., Coilleach, Spiddal, Galway, Ireland
| | - Shubhasmin Rana
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
| | - Stefanie Korntner
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
| | - Dimitrios I Zeugolis
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland.
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18
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Simpson LW, Good TA, Leach JB. Protein folding and assembly in confined environments: Implications for protein aggregation in hydrogels and tissues. Biotechnol Adv 2020; 42:107573. [PMID: 32512220 DOI: 10.1016/j.biotechadv.2020.107573] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 05/03/2020] [Accepted: 05/30/2020] [Indexed: 12/20/2022]
Abstract
In the biological milieu of a cell, soluble crowding molecules and rigid confined environments strongly influence whether the protein is properly folded, intrinsically disordered proteins assemble into distinct phases, or a denatured or aggregated protein species is favored. Such crowding and confinement factors act to exclude solvent volume from the protein molecules, resulting in an increased local protein concentration and decreased protein entropy. A protein's structure is inherently tied to its function. Examples of processes where crowding and confinement may strongly influence protein function include transmembrane protein dimerization, enzymatic activity, assembly of supramolecular structures (e.g., microtubules), nuclear condensates containing transcriptional machinery, protein aggregation in the contexts of disease and protein therapeutics. Historically, most protein structures have been determined from pure, dilute protein solutions or pure crystals. However, these are not the environments in which these proteins function. Thus, there has been an increased emphasis on analyzing protein structure and dynamics in more "in vivo-like" environments. Complex in vitro models using hydrogel scaffolds to study proteins may better mimic features of the in vivo environment. Therefore, analytical techniques need to be optimized for real-time analysis of proteins within hydrogel scaffolds.
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Affiliation(s)
- Laura W Simpson
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Eng 314, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Theresa A Good
- Division of Molecular and Cellular Biosciences, National Science Foundation, 2415 Eisenhower Ave, Alexandria, VA 22314, USA
| | - Jennie B Leach
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Eng 314, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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19
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Influence of crowding agents on the dynamics of a multidomain protein in its denatured state: a solvation approach. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:289-305. [PMID: 32399581 DOI: 10.1007/s00249-020-01435-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 03/26/2020] [Accepted: 04/28/2020] [Indexed: 01/01/2023]
Abstract
It is now well appreciated that the crowded intracellular environment significantly modulates an array of physiological processes including protein folding-unfolding, aggregation, and dynamics to name a few. In this work we have studied the dynamics of domain I of the protein human serum albumin (HSA) in its urea-induced denatured states, in the presence of a series of commonly used macromolecular crowding agents. HSA was labeled at Cys-34 (a free cysteine) in domain I with the fluorophore 6-bromoacetyl-2-dimethylaminonaphthalene (BADAN) to act as a solvation probe. In partially denatured states (2-6 M urea), lower crowder concentrations (~ < 125 g/L) induced faster dynamics, while the dynamics became slower beyond 150 g/L of crowders. We propose that this apparent switch in dynamics is an evidence of a crossover from soft (enthalpic) to hard-core (entropic) interactions between the protein and crowder molecules. That soft interactions are also important for the crowders used here was further confirmed by the appreciable shift in the wavelength of the emission maximum of BADAN, in particular for PEG8000 and Ficoll 70 at concentrations where the excluded volume effect is not dominant.
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20
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Matić M, Saurabh S, Hamacek J, Piazza F. Crowding-Induced Uncompetitive Inhibition of Lactate Dehydrogenase: Role of Entropic Pushing. J Phys Chem B 2020; 124:727-734. [PMID: 31917571 DOI: 10.1021/acs.jpcb.9b09596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cell is an extremely complex environment, notably highly crowded, segmented, and confining. Overall, there is overwhelming and ever-growing evidence that to understand how biochemical reactions proceed in vivo, one cannot separate the biochemical actors from their environment. Effects such as excluded volume, obstructed diffusion, weak nonspecific interactions, and fluctuations all team up to steer biochemical reactions often very far from what is observed in ideal conditions. In this paper, we use Ficoll PM70 and PEG 6000 to build an artificial crowded milieu of controlled composition and density in order to assess how such environments influence the biocatalytic activity of lactate dehydrogenase (LDH). Our measurements show that the normalized apparent affinity and maximum velocity decrease in the same fashion, a behavior reminiscent of uncompetitive inhibition, with PEG resulting in the largest reduction. In line with previous studies on other enzymes of the same family, and in agreement with the known role of a surface loop involved in enzyme isomerization and regulation of access to the active site, we suggest that the crowding matrix interferes with the conformational ensemble of the enzyme. This likely results in both impaired enzyme-complex isomerization and thwarted product release. Molecular dynamics simulations confirm that excluded-volume effects lead to an entropic force that effectively tends to push the loop closed, thereby effectively shifting the conformational ensemble of the enzyme in favor of a more stable complex isoform. Overall, our study substantiates the idea that most biochemical kinetics cannot be fully explained without including the subtle action of the environment where they take place naturally, in particular accounting for important factors such as excluded-volume effects and also weak nonspecific interactions when present, confinement, and fluctuations.
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Affiliation(s)
- Marin Matić
- Université d'Orléans and Centre de Biophysique Moléculaire (CBM), CNRS UPR 4301 , Rue Charles Sadron CS 80054 , 45071 Orléans , France
| | - Suman Saurabh
- Université d'Orléans and Centre de Biophysique Moléculaire (CBM), CNRS UPR 4301 , Rue Charles Sadron CS 80054 , 45071 Orléans , France
| | - Josef Hamacek
- Université d'Orléans and Centre de Biophysique Moléculaire (CBM), CNRS UPR 4301 , Rue Charles Sadron CS 80054 , 45071 Orléans , France
| | - Francesco Piazza
- Université d'Orléans and Centre de Biophysique Moléculaire (CBM), CNRS UPR 4301 , Rue Charles Sadron CS 80054 , 45071 Orléans , France
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21
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Perez CP, Elmore DE, Radhakrishnan ML. Computationally Modeling Electrostatic Binding Energetics in a Crowded, Dynamic Environment: Physical Insights from a Peptide–DNA System. J Phys Chem B 2019; 123:10718-10734. [DOI: 10.1021/acs.jpcb.9b09478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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22
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Adams LM, Andrews RJ, Hu QH, Schmit HL, Hati S, Bhattacharyya S. Crowder-Induced Conformational Ensemble Shift in Escherichia coli Prolyl-tRNA Synthetase. Biophys J 2019; 117:1269-1284. [PMID: 31542226 PMCID: PMC6818166 DOI: 10.1016/j.bpj.2019.08.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/27/2019] [Accepted: 08/28/2019] [Indexed: 01/08/2023] Open
Abstract
The effect of molecular crowding on the structure and function of Escherichia coli prolyl-transfer RNA synthetase (Ec ProRS), a member of the aminoacyl-transfer RNA synthetase family, has been investigated using a combined experimental and theoretical method. Ec ProRS is a multidomain enzyme; coupled-domain dynamics are essential for efficient catalysis. To gain insight into the mechanistic detail of the crowding effect, kinetic studies were conducted with varying concentrations and sizes of crowders. In parallel, spectroscopic and quantum chemical studies were employed to probe the "soft interactions" between crowders and protein side chains. Finally, the dynamics of the dimeric protein was examined in the presence of crowders using a long-duration (70 ns) classical molecular dynamic simulations. The results of the simulations revealed a shift in the conformational ensemble, which is consistent with the preferential exclusion of cosolutes. The "soft interactions" model of the crowding effect also explained the alteration in kinetic parameters. In summary, the study found that the effects of molecular crowding on both conformational dynamics and catalytic function are correlated in the multidomain Ec ProRS, an enzyme that is central to protein synthesis in all living cells. This study affirmed that large and small cosolutes have considerable impacts on the structure, dynamics, and function of modular proteins and therefore must be considered for stabilizing protein-based pharmaceuticals and industrial enzymes.
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Affiliation(s)
- Lauren M Adams
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Ryan J Andrews
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Quin H Hu
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Heidi L Schmit
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Sanchita Hati
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin.
| | - Sudeep Bhattacharyya
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin.
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23
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Kim DM, Yao X, Vanam RP, Marlow MS. Measuring the effects of macromolecular crowding on antibody function with biolayer interferometry. MAbs 2019; 11:1319-1330. [PMID: 31401928 PMCID: PMC6748605 DOI: 10.1080/19420862.2019.1647744] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Biotherapeutic proteins are commonly dosed at high concentrations into the blood, which is an inherently complex, crowded solution with substantial protein content. The effects of macromolecular crowding may lead to an appreciable level of non-specific hetero-association in this physiological environment. Therefore, developing a method to characterize the diverse consequences of non-specific interactions between proteins under such non-ideal, crowded conditions, which deviate substantially from those commonly employed for in vitro characterization, is vital to achieving a more complete picture of antibody function in a biological context. In this study, we investigated non-specific interactions between human serum albumin (HSA) and two monoclonal antibodies (mAbs) by static light scattering and determined these interactions are both ionic strength-dependent and mAb-dependent. Using biolayer interferometry (BLI), we assessed the effect of HSA on antigen binding by mAbs, demonstrating that these non-specific interactions have a functional impact on mAb:antigen interactions, particularly at low ionic strength. While this effect is mitigated at physiological ionic strength, our in vitro data support the notion that HSA in the blood may lead to non-specific interactions with mAbs in vivo, with a potential impact on their interactions with antigen. Furthermore, the BLI method offers a high-throughput advantage compared to orthogonal techniques such as analytical ultracentrifugation and is amenable to a greater variety of solution conditions compared to nuclear magnetic resonance spectroscopy. Our study demonstrates that BLI is a viable technology for examining the impact of non-specific interactions on specific biologically relevant interactions, providing a direct method to assess binding events in crowded conditions.
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Affiliation(s)
- Dorothy M Kim
- Pre-Clinical Development and Protein Chemistry, Regeneron Pharmaceuticals, Inc ., Tarrytown , NY , USA
| | - Xiao Yao
- Pre-Clinical Development and Protein Chemistry, Regeneron Pharmaceuticals, Inc ., Tarrytown , NY , USA
| | - Ram P Vanam
- Pre-Clinical Development and Protein Chemistry, Regeneron Pharmaceuticals, Inc ., Tarrytown , NY , USA
| | - Michael S Marlow
- Pre-Clinical Development and Protein Chemistry, Regeneron Pharmaceuticals, Inc ., Tarrytown , NY , USA.,Biotherapeutics Discovery, Boehringer Ingelheim Pharmaceuticals Inc ., Ridgefield , CT , USA
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24
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Guin D, Gruebele M. Weak Chemical Interactions That Drive Protein Evolution: Crowding, Sticking, and Quinary Structure in Folding and Function. Chem Rev 2019; 119:10691-10717. [PMID: 31356058 DOI: 10.1021/acs.chemrev.8b00753] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In recent years, better instrumentation and greater computing power have enabled the imaging of elusive biomolecule dynamics in cells, driving many advances in understanding the chemical organization of biological systems. The focus of this Review is on interactions in the cell that affect both biomolecular stability and function and modulate them. The same protein or nucleic acid can behave differently depending on the time in the cell cycle, the location in a specific compartment, or the stresses acting on the cell. We describe in detail the crowding, sticking, and quinary structure in the cell and the current methods to quantify them both in vitro and in vivo. Finally, we discuss protein evolution in the cell in light of current biophysical evidence. We describe the factors that drive protein evolution and shape protein interaction networks. These interactions can significantly affect the free energy, ΔG, of marginally stable and low-population proteins and, due to epistasis, direct the evolutionary pathways in an organism. We finally conclude by providing an outlook on experiments to come and the possibility of collaborative evolutionary biology and biophysical efforts.
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Affiliation(s)
- Drishti Guin
- Department of Chemistry , University of Illinois , Urbana , Illinois 61801 , United States
| | - Martin Gruebele
- Department of Chemistry , University of Illinois , Urbana , Illinois 61801 , United States.,Department of Physics , University of Illinois , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois , Urbana , Illinois 61801 , United States
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25
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Nguemaha V, Qin S, Zhou HX. Transfer Free Energies of Test Proteins Into Crowded Protein Solutions Have Simple Dependence on Crowder Concentration. Front Mol Biosci 2019; 6:39. [PMID: 31192219 PMCID: PMC6549383 DOI: 10.3389/fmolb.2019.00039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/07/2019] [Indexed: 01/14/2023] Open
Abstract
The effects of macromolecular crowding on the thermodynamic properties of test proteins are determined by the latter's transfer free energies from a dilute solution to a crowded solution. The transfer free energies in turn are determined by effective protein-crowder interactions. When these interactions are modeled at the all-atom level, the transfer free energies may defy simple predictions. Here we investigated the dependence of the transfer free energy (Δμ) on crowder concentration. We represented both the test protein and the crowder proteins atomistically, and used a general interaction potential consisting of hard-core repulsion, non-polar attraction, and solvent-screened electrostatic terms. The chemical potential was rigorously calculated by FMAP (Qin and Zhou, 2014), which entails expressing the protein-crowder interaction terms as correlation functions and evaluating them via fast Fourier transform (FFT). To high accuracy, the transfer free energy can be decomposed into an excluded-volume component (Δμe−v), arising from the hard-core repulsion, and a soft-attraction component (Δμs−a), arising from non-polar and electrostatic interactions. The decomposition provides physical insight into crowding effects, in particular why such effects are very modest on protein folding stability. Further decomposition of Δμs−a into non-polar and electrostatic components does not work, because these two types of interactions are highly correlated in contributing to Δμs−a. We found that Δμe−v fits well to the generalized fundamental measure theory (Qin and Zhou, 2010), which accounts for atomic details of the test protein but approximates the crowder proteins as spherical particles. Most interestingly, Δμs−a has a nearly linear dependence on crowder concentration. The latter result can be understood within a perturbed virial expansion of Δμ (in powers of crowder concentration), with Δμe−v as reference. Whereas the second virial coefficient deviates strongly from that of the reference system, higher virial coefficients are close to their reference counterparts, thus leaving the linear term to make the dominant contribution to Δμs−a.
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Affiliation(s)
- Valery Nguemaha
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, United States
| | - Sanbo Qin
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, United States
| | - Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, United States.,Department of Chemistry and Department of Physics, University of Illinois at Chicago, Chicago, IL, United States
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26
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Nishida N, Ito Y, Shimada I. In situ structural biology using in-cell NMR. Biochim Biophys Acta Gen Subj 2019; 1864:129364. [PMID: 31103749 DOI: 10.1016/j.bbagen.2019.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 01/23/2023]
Abstract
BACKGROUND Accumulating evidence from the experimental and computational studies indicated that the functional properties of proteins are different between in vitro and living cells, raising the necessity to examine the protein structure under the native intracellular milieu. To gain structural information of the proteins inside the living cells at an atomic resolution, in-cell NMR method has been developed for the past two decades. SCOPE OF REVIEW In this review, we will overview the recent progress in the methodological developments and the biological applications of in-cell NMR, and discuss the advances and challenges in this filed. MAJOR CONCLUSIONS A number of methods were developed to enrich the isotope-labeled proteins inside the cells, enabling the in-cell NMR observation of bacterial cells as well as eukaryotic cells. In-cell NMR has been applied to various biological systems, including de novo structure determinations, protein/protein or protein/drug interactions, and monitoring of chemical reactions exerted by the endogenous enzymes. The bioreactor system, in which the cells in the NMR tube are perfused by fresh culture medium, enabled the long-term in-cell NMR measurements, and the real-time observations of intracellular responses upon external stimuli. GENERAL SIGNIFICANCE In-cell NMR has become a unique technology for its ability to obtain the function-related structural information of the target proteins under the physiological or pathological cellular environments, which cannot be reconstituted in vitro.
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Affiliation(s)
- Noritaka Nishida
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yutaka Ito
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji, Tokyo 192-0373, Japan.
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Brylski O, Ebbinghaus S, Mueller JW. Melting Down Protein Stability: PAPS Synthase 2 in Patients and in a Cellular Environment. Front Mol Biosci 2019; 6:31. [PMID: 31131283 PMCID: PMC6509946 DOI: 10.3389/fmolb.2019.00031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/15/2019] [Indexed: 12/17/2022] Open
Abstract
Within the crowded and complex environment of the cell, a protein experiences stabilizing excluded-volume effects and destabilizing quinary interactions with other proteins. Which of these prevail, needs to be determined on a case-by-case basis. PAPS synthases are dimeric and bifunctional enzymes, providing activated sulfate in the form of 3′-phosphoadenosine-5′-phosphosulfate (PAPS) for sulfation reactions. The human PAPS synthases PAPSS1 and PAPSS2 differ significantly in their protein stability as PAPSS2 is a naturally fragile protein. PAPS synthases bind a series of nucleotide ligands and some of them markedly stabilize these proteins. PAPS synthases are of biomedical relevance as destabilizing point mutations give rise to several pathologies. Genetic defects in PAPSS2 have been linked to bone and cartilage malformations as well as a steroid sulfation defect. All this makes PAPS synthases ideal to study protein unfolding, ligand binding, and the stabilizing and destabilizing factors in their cellular environment. This review provides an overview on current concepts of protein folding and stability and links this with our current understanding of the different disease mechanisms of PAPSS2-related pathologies with perspectives for future research and application.
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Affiliation(s)
- Oliver Brylski
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Jonathan W Mueller
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
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Polydispersity and negative charge are key modulators of extracellular matrix deposition under macromolecular crowding conditions. Acta Biomater 2019; 88:197-210. [PMID: 30831324 DOI: 10.1016/j.actbio.2019.02.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/15/2019] [Accepted: 02/28/2019] [Indexed: 12/22/2022]
Abstract
Macromolecular crowding is a biophysical phenomenon that stems from the volume excluded by macromolecules, as they undergo steric repulsion and electrostatic interactions. The excluded volume depends on the shape, size, charge and polydispersity of the molecules. Although theoretical/computational models have been used to assess the influence of macromolecular crowding in biological media, real-time experiments are scarce. Herein, we evaluated the influence of hydrodynamic radius, charge and polydispersity of (a) various concentrations of different crowders (carrageenan, Ficoll™ and dextran sulphate); (b) various molecular weights of different crowders (70, 400 and 100 kDa of Ficoll™ and 10, 100 and 500 kDa of dextran sulphate) and (c) various cocktails of the same crowders (cocktails of various concentrations of different molecular weights Ficoll™ and dextran sulphate) on extracellular matrix deposition in human dermal fibroblast culture. The use of crowding cocktails with different molecular weight/concentrations of Ficoll™ or dextran sulphate molecules led to increased polydispersity and enhanced collagen type I deposition in comparison to their mono-domain counterparts. Carrageenan, however, induced the highest deposition of collagen type I due to its negative charge and inherent polydispersity. Our data contribute to a better understanding of the influence of the biophysical properties of the crowders on extracellular matrix deposition in vitro. STATEMENT OF SIGNIFICANCE: Macromolecular crowding is a biophysical phenomenon that accelerates and enhances extracellular matrix deposition in cell culture systems. Herein, we demonstrate that negatively charged and polydispersed macromolecules or cocktails of macromolecules, as opposed to neutral and monodomain macromolecules, induce highest extracellular matrix deposition in human dermal fibroblast cultures.
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Dey P, Bhattacherjee A. Disparity in anomalous diffusion of proteins searching for their target DNA sites in a crowded medium is controlled by the size, shape and mobility of macromolecular crowders. SOFT MATTER 2019; 15:1960-1969. [PMID: 30539954 DOI: 10.1039/c8sm01933a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Using extensive computer simulations, we analyzed the role of physical properties of molecular crowding agents such as size, shape and mobility in the target search dynamics of DNA binding proteins. Our main result is that the sub-diffusive dynamics of a protein inside a crowded medium strongly depends on the crowder properties and also on the protein's mode of diffusion. For instance, while scanning the DNA one-dimensionally, the protein dynamics does not vary with the change in crowder properties. Conversely, the diffusion exponent varies non-monotonically during 3D diffusion and is maximally affected when the crowders match the protein physically. The investigation shows that the effect stems from the ruggedness of the associated potential energy landscape, which is regulated by the protein-crowder and DNA-crowder interactions. Our findings have broad significance in understanding the target search dynamics of proteins on DNA in crowded cellular milieu and selecting appropriate crowding agents when designing in vitro experiments.
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Affiliation(s)
- Pinki Dey
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
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30
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Fonin AV, Darling AL, Kuznetsova IM, Turoverov KK, Uversky VN. Intrinsically disordered proteins in crowded milieu: when chaos prevails within the cellular gumbo. Cell Mol Life Sci 2018; 75:3907-3929. [PMID: 30066087 PMCID: PMC11105604 DOI: 10.1007/s00018-018-2894-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 12/18/2022]
Abstract
Effects of macromolecular crowding on structural and functional properties of ordered proteins, their folding, interactability, and aggregation are well documented. Much less is known about how macromolecular crowding might affect structural and functional behaviour of intrinsically disordered proteins (IDPs) or intrinsically disordered protein regions (IDPRs). To fill this gap, this review represents a systematic analysis of the available literature data on the behaviour of IDPs/IDPRs in crowded environment. Although it was hypothesized that, due to the excluded-volume effects present in crowded environments, IDPs/IDPRs would invariantly fold in the presence of high concentrations of crowding agents or in the crowded cellular environment, accumulated data indicate that, based on their response to the presence of crowders, IDPs/IDPRs can be grouped into three major categories, foldable, non-foldable, and unfoldable. This is because natural cellular environment is not simply characterized by the presence of high concentration of "inert" macromolecules, but represents an active milieu, components of which are engaged in direct physical interactions and soft interactions with target proteins. Some of these interactions with cellular components can cause (local) unfolding of query proteins. In other words, since crowding can cause both folding and unfolding of an IDP or its regions, the outputs of the placing of a query protein to the crowded environment would depend on the balance between these two processes. As a result, and because of the spatio-temporal heterogeneity in structural organization of IDPs, macromolecular crowding can differently affect structures of different IDPs. Recent studies indicate that some IDPs are able to undergo liquid-liquid-phase transitions leading to the formation of various proteinaceous membrane-less organelles (PMLOs). Although interiors of such PMLOs are self-crowded, being characterized by locally increased concentrations of phase-separating IDPs, these IDPs are minimally foldable or even non-foldable at all (at least within the physiologically safe time-frame of normal PMLO existence).
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Affiliation(s)
- Alexander V Fonin
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - April L Darling
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Irina M Kuznetsova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
- St. Petersburg State Polytechnical University, St. Petersburg, Russian Federation
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
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31
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Zeng J, Huang Z. From Levinthal's Paradox to the Effects of Cell Environmental Perturbation on Protein Folding. Curr Med Chem 2018; 26:7537-7554. [PMID: 30332937 DOI: 10.2174/0929867325666181017160857] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/04/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND The rapidly increasing number of known protein sequences calls for more efficient methods to predict the Three-Dimensional (3D) structures of proteins, thus providing basic knowledge for rational drug design. Understanding the folding mechanism of proteins is valuable for predicting their 3D structures and for designing proteins with new functions and medicinal applications. Levinthal's paradox is that although the astronomical number of conformations possible even for proteins as small as 100 residues cannot be fully sampled, proteins in nature normally fold into the native state within timescales ranging from microseconds to hours. These conflicting results reveal that there are factors in organisms that can assist in protein folding. METHODS In this paper, we selected a crowded cell-like environment and temperature, and the top three Posttranslational Modifications (PTMs) as examples to show that Levinthal's paradox does not reflect the folding mechanism of proteins. We then revealed the effects of these factors on protein folding. RESULTS The results summarized in this review indicate that a crowded cell-like environment, temperature, and the top three PTMs reshape the Free Energy Landscapes (FELs) of proteins, thereby regulating the folding process. The balance between entropy and enthalpy is the key to understanding the effect of the crowded cell-like environment and PTMs on protein folding. In addition, the stability/flexibility of proteins is regulated by temperature. CONCLUSION This paper concludes that the cellular environment could directly intervene in protein folding. The long-term interactions of the cellular environment and sequence evolution may enable proteins to fold efficiently. Therefore, to correctly understand the folding mechanism of proteins, the effect of the cellular environment on protein folding should be considered.
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Affiliation(s)
- Juan Zeng
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China.,Laboratory of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Zunnan Huang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China
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32
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Hata Y, Sawada T, Serizawa T. Macromolecular crowding for materials-directed controlled self-assembly. J Mater Chem B 2018; 6:6344-6359. [PMID: 32254643 DOI: 10.1039/c8tb02201a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Macromolecular crowding refers to intracellular environments where various macromolecules, including proteins and nucleic acids, are present at high total concentrations. Its influence on biological processes has been investigated using a highly concentrated in vitro solution of water-soluble polymers as a model. Studies have revealed significant effects of macromolecular crowding on the thermodynamic equilibria and dynamics of biomolecular self-assembly in vivo. Recently, macromolecular crowding has attracted materials scientists, especially those in bio-related areas, as a tool to control molecular/colloidal self-assembly. Macromolecular crowding has been exploited to control the structure of supramolecular materials, assemble nanomaterials, and improve the performance of polymeric materials. Furthermore, nanostructured materials have been shown to be an interesting alternative to water-soluble polymers for creating crowded environments for controlled self-assembly. In this review article, we summarize recent progress in research on macromolecular crowding for controlled self-assembly in bio-related materials chemistry.
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Affiliation(s)
- Yuuki Hata
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1-H121 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
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33
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Ferreira LA, Walczyk Mooradally A, Zaslavsky B, Uversky VN, Graether SP. Effect of an Intrinsically Disordered Plant Stress Protein on the Properties of Water. Biophys J 2018; 115:1696-1706. [PMID: 30297135 DOI: 10.1016/j.bpj.2018.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/09/2018] [Accepted: 09/18/2018] [Indexed: 11/19/2022] Open
Abstract
Dehydrins are plant proteins that are able to protect plants from various forms of dehydrative stress such as drought, cold, and high salinity. Dehydrins can prevent enzymes from losing activity after freeze/thaw treatments. Previous studies had suggested that the dehydrins function by a molecular shield effect, essentially preventing a denatured enzyme from aggregating with another enzyme. Therefore, the larger the dehydrin, the larger the shield and theoretically the more effective the protection. Although this relationship holds for smaller dehydrins, it fails to explain why larger dehydrins are less efficient than would be predicted from their size. Using solvatochromic dyes to probe the solvent features of water, we first confirm that the dehydrins do not bind the dyes, which would interfere with interpretation of the data. We then show that the dehydrins have an effect on three solvent properties of water (dipolarity/polarizability, hydrogen-bond donor acidity and hydrogen-bond acceptor basicity), which can contribute to the protective mechanism of these proteins. Interpretation of these data suggests that although polyethylene glycol and dehydrins have similar protective effects, dehydrins may more efficiently modify the hydrogen-bonding ability of bulk water to prevent enzyme denaturation. This possibly explains why dehydrins recover slightly more enzyme activity than polyethylene glycol.
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Affiliation(s)
| | | | | | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida; Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation.
| | - Steffen P Graether
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
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34
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Kumar R, Sharma D, Kumar V, Kumar R. Factors defining the effects of macromolecular crowding on dynamics and thermodynamic stability of heme proteins in-vitro. Arch Biochem Biophys 2018; 654:146-162. [DOI: 10.1016/j.abb.2018.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 11/28/2022]
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35
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Majumdar BB, Ebbinghaus S, Heyden M. Macromolecular crowding effects in flexible polymer solutions. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2018. [DOI: 10.1142/s0219633618400060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biological environments are often “crowded” due to high concentrations (300–400[Formula: see text]g/L) of macromolecules. Computational modeling approaches like Molecular Dynamics (MD), rigid-body Brownian Dynamics and Monte Carlo simulations have recently emerged, which allow to study the effects macromolecular crowding at a microscopic level and to provide complementary information to experiments. Here, we use a recently introduced multiple-conformation Monte Carlo (mcMC) approach in order to study the influence of intermolecular interactions on the structural equilibrium of flexible polyethylene glycol (PEG) polymers under self-crowding conditions. The large conformational space accessible to PEG polymers allows us to evaluate the general applicability of the mcMC approach, which describes the intramolecular degrees of freedom by a finite-size ensemble of discrete conformations. Despite the simplicity of the approach, we show that influences of intermolecular interactions on the intramolecular free energy surface can be described qualitatively using mcMC. By varying the magnitude of distinct terms in the intermolecular potential, we can further study the compensating effects of repulsive and nonspecific attractive intermolecular interactions, which favor compact and extended polymer states, respectively. We use our simulation results to derive an analytical model that describes the effects of intermolecular interactions on the stability of PEG polymer conformations as a function of the radius of gyration and the corresponding solvent accessible surface. We use this model to confirm the role of molecular surfaces for attractive interactions that can counteract excluded volume effects. Extrapolation of the model further allows for the analysis of scenarios that are not easily accessible to direct simulations as described here.
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Affiliation(s)
- Bibhab Bandhu Majumdar
- Theoretische Chemie, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, Technical University, Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Matthias Heyden
- School of Molecular Sciences, Arizona State University, 551 E. University Dr., Tempe, AZ 85281, USA
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36
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Marianelli AM, Miller BM, Keating CD. Impact of macromolecular crowding on RNA/spermine complex coacervation and oligonucleotide compartmentalization. SOFT MATTER 2018; 14:368-378. [PMID: 29265152 DOI: 10.1039/c7sm02146a] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the effect of neutral macromolecular crowders poly(ethylene glycol) (PEG) (8 kDa) and Ficoll (70 kDa) on liquid-liquid phase separation in a polyuridylic acid (polyU)/spermine complex coacervate system. The addition of PEG decreased both the amount of spermine required for phase separation and the coacervation temperature (TC). We interpret these effects on phase behavior as arising due to excluded volume and preferential interactions on both the secondary structure/condensation of spermine-associated polyU molecules and on the association of soluble polyU/spermine polyelectrolyte complexes to form coacervate droplets. Examination of coacervates formed in the presence of fluorescently-labeled PEG or Ficoll crowders indicated that Ficoll is accumulated while PEG is excluded from the coacervate phase, which provides further insight into the differences in phase behavior. Crowding agents impact distribution of a biomolecular solute: partitioning of a fluorescently-labeled U15 RNA oligomer into the polyU/spermine coacervates was increased approximately two-fold by 20 wt% Ficoll 70 kDa and by more than two orders of magnitude by 20 wt% PEG 8 kDa. The volume of the coacervate phase decreased in the presence of crowder relative to a dilute buffer solution. These findings indicate that potential impacts of macromolecular crowding on phase behavior and solute partitioning should be considered in model systems for intracellular membraneless organelles.
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Affiliation(s)
- A M Marianelli
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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37
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Gladstein S, Stawarz A, Almassalha LM, Cherkezyan L, Chandler JE, Zhou X, Subramanian H, Backman V. Measuring Nanoscale Chromatin Heterogeneity with Partial Wave Spectroscopic Microscopy. Methods Mol Biol 2018; 1745:337-360. [PMID: 29476478 DOI: 10.1007/978-1-4939-7680-5_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite extensive research in the area, current understanding of the structural organization of higher-order chromatin topology (between 20 and 200 nm) is limited due to a lack of proper imaging techniques at these length scales. The organization of chromatin at these scales defines the physical context (nanoenvironment) in which many important biological processes occur. Improving our understanding of the nanoenvironment is crucial because it has been shown to play a critical functional role in the regulation of chemical reactions. Recent progress in partial wave spectroscopic (PWS) microscopy enables real-time measurement of higher-order chromatin organization within label-free live cells. Specifically, PWS quantifies the nanoscale variations in mass density (heterogeneity) within the cell. These advancements have made it possible to study the functional role of chromatin topology, such as its regulation of the global transcriptional state of the cell and its role in the development of cancer. In this chapter, the importance of studying chromatin topology is explained, the theory and instrumentation of PWS are described, the measurements and analysis processes for PWS are laid out in detail, and common issues, troubleshooting steps, and validation techniques are provided.
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Affiliation(s)
- Scott Gladstein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Andrew Stawarz
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Lusik Cherkezyan
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - John E Chandler
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Xiang Zhou
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | | | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
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38
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Gao M, Held C, Patra S, Arns L, Sadowski G, Winter R. Crowders and Cosolvents-Major Contributors to the Cellular Milieu and Efficient Means to Counteract Environmental Stresses. Chemphyschem 2017; 18:2951-2972. [DOI: 10.1002/cphc.201700762] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/15/2017] [Indexed: 01/27/2023]
Affiliation(s)
- Mimi Gao
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Christoph Held
- TU Dortmund University; Department of Biochemical and Chemical Engineering; Emil-Figge-Str. 70 44227 Dortmund Germany
| | - Satyajit Patra
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Loana Arns
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Gabriele Sadowski
- TU Dortmund University; Department of Biochemical and Chemical Engineering; Emil-Figge-Str. 70 44227 Dortmund Germany
| | - Roland Winter
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
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39
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Kumar S, Sharma D, Kumar R. Role of Macromolecular Crowding on Stability and Iron Release Kinetics of Serum Transferrin. J Phys Chem B 2017; 121:8669-8683. [PMID: 28837344 DOI: 10.1021/acs.jpcb.7b05702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The macromolecular crowding influences the structural stability and functional properties of transferrin (Tf). The equilibrium as well as kinetic studies of Tf at different concentrations of crowding agents (dextran 40, dextran 70, and ficoll 70) and at a fixed concentration of dextran 40 under different concentrations of NaCl at pH 7.4 and 5.6 (±1) revealed that (i) the crowder environment increases the diferric-Tf (Fe2Tf) stability against iron loss and overall denaturation of the protein, (ii) both in the absence and presence of crowder, the presence of salt promotes the loss of iron and overall denaturation of Fe2Tf which is due to ionic screening of electrostatic interactions, (iii) the crowder environment retards iron release from monoferric N-lobe of Tf (FeNTf) by increasing enthalpic barrier, (iv) the retardation of iron release by crowding is enthalpically dominated than the entropic one, (v) both in the absence and presence of crowder, the presence of salt accelerates the iron release from FeNTf due to ionic screening of electrostatic interactions and anion binding to KISAB sites, and (vi) the crowders environment is unable to diminish (a) the salt-induced destabilization of Fe2Tf against the loss of iron and overall denaturation and (b) the anion effect and ionic screening of diffusive counterions responsible to promote iron release from FeNTf.
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Affiliation(s)
- Sandeep Kumar
- School of Chemistry and Biochemistry, Thapar University , Patiala 147004, India
| | - Deepak Sharma
- Council of Scientific and Industrial Research, Institute of Microbial Technology , Sector 39A, Chandigarh, India
| | - Rajesh Kumar
- Centre for Chemical Sciences, School of Bassic and Applied Sciences, Central University of Punjab , Bathinda 151001, India
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40
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Xu G, Zhao J, Cheng K, Wu Q, Liu X, Liu M, Li C. The Effects of Macromolecular Crowding on Calmodulin Structure and Function. Chemistry 2017; 23:6736-6740. [DOI: 10.1002/chem.201700367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Indexed: 02/07/2023]
Affiliation(s)
- Guohua Xu
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
| | - Jiajing Zhao
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
- Graduate University of Chinese Academy of Sciences; Beijing 100029 P. R. China
| | - Kai Cheng
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
- Graduate University of Chinese Academy of Sciences; Beijing 100029 P. R. China
| | - Qiong Wu
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
| | - Xiaoli Liu
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics; National Center for Magnetic Resonance in Wuhan; Wuhan Institute of Physics and Mathematics; Chinese Academy of Sciences; Wuhan 430071 P. R. China
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41
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Shahid S, Hassan MI, Islam A, Ahmad F. Size-dependent studies of macromolecular crowding on the thermodynamic stability, structure and functional activity of proteins: in vitro and in silico approaches. Biochim Biophys Acta Gen Subj 2017; 1861:178-197. [DOI: 10.1016/j.bbagen.2016.11.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 11/27/2022]
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42
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Almassalha LM, Tiwari A, Ruhoff PT, Stypula-Cyrus Y, Cherkezyan L, Matsuda H, Dela Cruz MA, Chandler JE, White C, Maneval C, Subramanian H, Szleifer I, Roy HK, Backman V. The Global Relationship between Chromatin Physical Topology, Fractal Structure, and Gene Expression. Sci Rep 2017; 7:41061. [PMID: 28117353 PMCID: PMC5259786 DOI: 10.1038/srep41061] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 12/12/2016] [Indexed: 02/07/2023] Open
Abstract
Most of what we know about gene transcription comes from the view of cells as molecular machines: focusing on the role of molecular modifications to the proteins carrying out transcriptional reactions at a loci-by-loci basis. This view ignores a critical reality: biological reactions do not happen in an empty space, but in a highly complex, interrelated, and dense nanoenvironment that profoundly influences chemical interactions. We explored the relationship between the physical nanoenvironment of chromatin and gene transcription in vitro. We analytically show that changes in the fractal dimension, D, of chromatin correspond to simultaneous increases in chromatin accessibility and compaction heterogeneity. Using these predictions, we demonstrate experimentally that nanoscopic changes to chromatin D within thirty minutes correlate with concomitant enhancement and suppression of transcription. Further, we show that the increased heterogeneity of physical structure of chromatin due to increase in fractal dimension correlates with increased heterogeneity of gene networks. These findings indicate that the higher order folding of chromatin topology may act as a molecular-pathway independent code regulating global patterns of gene expression. Since physical organization of chromatin is frequently altered in oncogenesis, this work provides evidence pairing molecular function to physical structure for processes frequently altered during tumorigenesis.
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Affiliation(s)
- L M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - A Tiwari
- Section of Gastroenterology, Boston Medical Center/Boston University School of Medicine, Boston, Massachusetts, 02118, USA
| | - P T Ruhoff
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Y Stypula-Cyrus
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - L Cherkezyan
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - H Matsuda
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - M A Dela Cruz
- Section of Gastroenterology, Boston Medical Center/Boston University School of Medicine, Boston, Massachusetts, 02118, USA
| | - J E Chandler
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - C White
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - C Maneval
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - H Subramanian
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA
| | - I Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA.,Department of Chemistry, Northwestern University, Evanston, Illinois, 60208, USA.,Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, 60208, USA
| | - H K Roy
- Section of Gastroenterology, Boston Medical Center/Boston University School of Medicine, Boston, Massachusetts, 02118, USA
| | - V Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208, USA.,Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, 60208, USA
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43
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Biswas S, Mukherjee SK, Chowdhury PK. Crowder-Induced Rigidity in a Multidomain Protein: Insights from Solvation. J Phys Chem B 2016; 120:12501-12510. [DOI: 10.1021/acs.jpcb.6b10478] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Saikat Biswas
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sanjib Kumar Mukherjee
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pramit Kumar Chowdhury
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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44
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Ando T, Yu I, Feig M, Sugita Y. Thermodynamics of Macromolecular Association in Heterogeneous Crowding Environments: Theoretical and Simulation Studies with a Simplified Model. J Phys Chem B 2016; 120:11856-11865. [PMID: 27797534 DOI: 10.1021/acs.jpcb.6b06243] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cytoplasm of a cell is crowded with many different kinds of macromolecules. The macromolecular crowding affects the thermodynamics and kinetics of biological reactions in a living cell, such as protein folding, association, and diffusion. Theoretical and simulation studies using simplified models focus on the essential features of the crowding effects and provide a basis for analyzing experimental data. In most of the previous studies on the crowding effects, a uniform crowder size is assumed, which is in contrast to the inhomogeneous size distribution of macromolecules in a living cell. Here, we evaluate the free energy changes upon macromolecular association in a cell-like inhomogeneous crowding system via a theory of hard-sphere fluids and free energy calculations using Brownian dynamics trajectories. The inhomogeneous crowding model based on 41 different types of macromolecules represented by spheres with different radii mimics the physiological concentrations of macromolecules in the cytoplasm of Mycoplasma genitalium. The free energy changes of macromolecular association evaluated by the theory and simulations were in good agreement with each other. The crowder size distribution affects both specific and nonspecific molecular associations, suggesting that not only the volume fraction but also the size distribution of macromolecules are important factors for evaluating in vivo crowding effects. This study relates in vitro experiments on macromolecular crowding to in vivo crowding effects by using the theory of hard-sphere fluids with crowder-size heterogeneity.
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Affiliation(s)
- Tadashi Ando
- RIKEN Quantitative Biology Center (QBiC), Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Isseki Yu
- RIKEN Theoretical Molecular Science Laboratory and iTHES, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Michael Feig
- RIKEN Quantitative Biology Center (QBiC), Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,Department of Biochemistry & Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Yuji Sugita
- RIKEN Quantitative Biology Center (QBiC), Integrated Innovation Building 7F, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,RIKEN Theoretical Molecular Science Laboratory and iTHES, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.,RIKEN Advanced Institute for Computational Science (AICS), 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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45
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Musiani F, Giorgetti A. Protein Aggregation and Molecular Crowding: Perspectives From Multiscale Simulations. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:49-77. [PMID: 28109331 DOI: 10.1016/bs.ircmb.2016.08.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cells are extremely crowded environments, thus the use of diluted salted aqueous solutions containing a single protein is too simplistic to mimic the real situation. Macromolecular crowding might affect protein structure, folding, shape, conformational stability, binding of small molecules, enzymatic activity, interactions with cognate biomolecules, and pathological aggregation. The latter phenomenon typically leads to the formation of amyloid fibrils that are linked to several lethal neurodegenerative diseases, but that can also play a functional role in certain organisms. The majority of molecular simulations performed before the last few years were conducted in diluted solutions and were restricted both in the timescales and in the system dimensions by the available computational resources. In recent years, several computational solutions were developed to get close to physiological conditions. In this review we summarize the main computational techniques used to tackle the issue of protein aggregation both in a diluted and in a crowded environment.
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Affiliation(s)
- F Musiani
- Laboratory of Bioinorganic Chemistry, University of Bologna, Bologna, Italy.
| | - A Giorgetti
- Applied Bioinformatics Group, University of Verona, Verona, Italy.
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46
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Qin S, Zhou HX. Protein folding, binding, and droplet formation in cell-like conditions. Curr Opin Struct Biol 2016; 43:28-37. [PMID: 27771543 DOI: 10.1016/j.sbi.2016.10.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/07/2016] [Indexed: 10/20/2022]
Abstract
The many bystander macromolecules in the crowded cellular environments present both steric repulsion and weak attraction to proteins undergoing folding or binding and hence impact the thermodynamic and kinetic properties of these processes. The weak but nonrandom binding with bystander macromolecules may facilitate subcellular localization and biological function. Weak binding also leads to the emergence of a protein-rich droplet phase, which has been implicated in regulating a variety of cellular functions. All these important problems can now be addressed by realistic modeling of intermolecular interactions. Configurational sampling of concentrated protein solutions is an ongoing challenge.
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Affiliation(s)
- Sanbo Qin
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA.
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47
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Rapid, Portable, Multiplexed Detection of Bacterial Pathogens Directly from Clinical Sample Matrices. BIOSENSORS-BASEL 2016; 6:bios6040049. [PMID: 27669320 PMCID: PMC5192369 DOI: 10.3390/bios6040049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 09/16/2016] [Accepted: 09/20/2016] [Indexed: 12/23/2022]
Abstract
Enteric and diarrheal diseases are a major cause of childhood illness and death in countries with developing economies. Each year, more than half of a million children under the age of five die from these diseases. We have developed a portable, microfluidic platform capable of simultaneous, multiplexed detection of several of the bacterial pathogens that cause these diseases. This platform can perform fast, sensitive immunoassays directly from relevant, complex clinical matrices such as stool without extensive sample cleanup or preparation. Using only 1 µL of sample per assay, we demonstrate simultaneous multiplexed detection of four bacterial pathogens implicated in diarrheal and enteric diseases in less than 20 min.
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48
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Rivas G, Minton AP. Macromolecular Crowding In Vitro, In Vivo, and In Between. Trends Biochem Sci 2016; 41:970-981. [PMID: 27669651 DOI: 10.1016/j.tibs.2016.08.013] [Citation(s) in RCA: 299] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
Biochemical processes take place in heterogeneous and highly volume-occupied or crowded environments that can considerably influence the reactivity and distribution of participating macromolecules. We summarize here the thermodynamic consequences of excluded-volume and long-range nonspecific intermolecular interactions for macromolecular reactions in volume-occupied media. In addition, we summarize and compare the information content of studies of crowding in vitro and in vivo. We emphasize the importance of characterizing the behavior not only of labeled tracer macromolecules but also the composition and behavior of unlabeled macromolecules in the immediate vicinity of the tracer. Finally, we propose strategies for extending quantitative analyses of crowding in simple model systems to increasingly complex media up to and including intact cells.
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Affiliation(s)
- Germán Rivas
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
| | - Allen P Minton
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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49
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Im W, Liang J, Olson A, Zhou HX, Vajda S, Vakser IA. Challenges in structural approaches to cell modeling. J Mol Biol 2016; 428:2943-64. [PMID: 27255863 PMCID: PMC4976022 DOI: 10.1016/j.jmb.2016.05.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/19/2016] [Accepted: 05/24/2016] [Indexed: 11/17/2022]
Abstract
Computational modeling is essential for structural characterization of biomolecular mechanisms across the broad spectrum of scales. Adequate understanding of biomolecular mechanisms inherently involves our ability to model them. Structural modeling of individual biomolecules and their interactions has been rapidly progressing. However, in terms of the broader picture, the focus is shifting toward larger systems, up to the level of a cell. Such modeling involves a more dynamic and realistic representation of the interactomes in vivo, in a crowded cellular environment, as well as membranes and membrane proteins, and other cellular components. Structural modeling of a cell complements computational approaches to cellular mechanisms based on differential equations, graph models, and other techniques to model biological networks, imaging data, etc. Structural modeling along with other computational and experimental approaches will provide a fundamental understanding of life at the molecular level and lead to important applications to biology and medicine. A cross section of diverse approaches presented in this review illustrates the developing shift from the structural modeling of individual molecules to that of cell biology. Studies in several related areas are covered: biological networks; automated construction of three-dimensional cell models using experimental data; modeling of protein complexes; prediction of non-specific and transient protein interactions; thermodynamic and kinetic effects of crowding; cellular membrane modeling; and modeling of chromosomes. The review presents an expert opinion on the current state-of-the-art in these various aspects of structural modeling in cellular biology, and the prospects of future developments in this emerging field.
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Affiliation(s)
- Wonpil Im
- Center for Computational Biology and Department of Molecular Biosciences, The University of Kansas, Lawrence, KS 66047, United States.
| | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, United States.
| | - Arthur Olson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States.
| | - Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, United States.
| | - Sandor Vajda
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States.
| | - Ilya A Vakser
- Center for Computational Biology and Department of Molecular Biosciences, The University of Kansas, Lawrence, KS 66047, United States.
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50
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Gnutt D, Ebbinghaus S. The macromolecular crowding effect--from in vitro into the cell. Biol Chem 2016; 397:37-44. [PMID: 26351910 DOI: 10.1515/hsz-2015-0161] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/13/2015] [Indexed: 01/18/2023]
Abstract
The influence of the cellular milieu, a complex and crowded solvent, is often neglected when biomolecular structure and function are studied in vitro. To mimic the cellular environment, crowding effects are commonly induced in vitro using artificial crowding agents like Ficoll or dextran. However, it is unclear if such effects are also observed in cellulo. Diverging results on protein stability in living cells point out the need for new quantitative methods to investigate the contributions of excluded volume and nonspecific interactions to the cellular crowding effect. We show how new crowding sensitive probes may be utilized to directly investigate crowding effects in living cells. Moreover, we discuss processes where crowding effects could play a crucial role in molecular cell biology.
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