1
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Santema LL, Rotilio L, Xiang R, Tjallinks G, Guallar V, Mattevi A, Fraaije MW. Discovery and biochemical characterization of thermostable glycerol oxidases. Appl Microbiol Biotechnol 2024; 108:61. [PMID: 38183484 PMCID: PMC10771423 DOI: 10.1007/s00253-023-12883-9] [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: 06/23/2023] [Revised: 10/10/2023] [Accepted: 10/20/2023] [Indexed: 01/08/2024]
Abstract
Alditol oxidases are promising tools for the biocatalytic oxidation of glycerol to more valuable chemicals. By integrating in silico bioprospecting with cell-free protein synthesis and activity screening, an effective pipeline was developed to rapidly identify enzymes that are active on glycerol. Three thermostable alditol oxidases from Actinobacteria Bacterium, Streptomyces thermoviolaceus, and Thermostaphylospora chromogena active on glycerol were discovered. The characterization of these three flavoenzymes demonstrated their glycerol oxidation activities, preference for alkaline conditions, and excellent thermostabilities with melting temperatures higher than 75 °C. Structural elucidation of the alditol oxidase from Actinobacteria Bacterium highlighted a constellation of side chains that engage the substrate through several hydrogen bonds, a histidine residue covalently bound to the FAD prosthetic group, and a tunnel leading to the active site. Upon computational simulations of substrate binding, a double mutant targeting a residue pair at the tunnel entrance was created and found to display an improved thermal stability and catalytic efficiency for glycerol oxidation. The hereby described alditol oxidases form a valuable panel of oxidative biocatalysts that can perform regioselective oxidation of glycerol and other polyols. KEY POINTS: • Rapid pipeline designed to identify putative oxidases • Biochemical and structural characterization of alditol oxidases • Glycerol oxidation to more valuable derivatives.
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Affiliation(s)
- Lars L Santema
- Molecular Enzymology, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - Laura Rotilio
- Department of Biology and Biotechnology, University of Pavia, via Ferrata 9, 27100, Pavia, Italy
| | - Ruite Xiang
- Barcelona Supercomputing Center (BSC), Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08034, Spain
| | - Gwen Tjallinks
- Molecular Enzymology, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - Victor Guallar
- Barcelona Supercomputing Center (BSC), Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08034, Spain.
| | - Andrea Mattevi
- Department of Biology and Biotechnology, University of Pavia, via Ferrata 9, 27100, Pavia, Italy.
| | - Marco W Fraaije
- Molecular Enzymology, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands.
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2
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Dobersberger M, Sumesgutner D, Zajc CU, Salzer B, Laurent E, Emminger D, Sylvander E, Lehner E, Teufl M, Seigner J, Bobbili MR, Kunert R, Lehner M, Traxlmayr MW. An engineering strategy to target activated EGFR with CAR T cells. CELL REPORTS METHODS 2024; 4:100728. [PMID: 38492569 PMCID: PMC11045874 DOI: 10.1016/j.crmeth.2024.100728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/18/2024] [Accepted: 02/16/2024] [Indexed: 03/18/2024]
Abstract
Chimeric antigen receptor (CAR) T cells have shown remarkable response rates in hematological malignancies. In contrast, CAR T cell treatment of solid tumors is associated with several challenges, in particular the expression of most tumor-associated antigens at lower levels in vital organs, resulting in on-target/off-tumor toxicities. Thus, innovative approaches to improve the tumor specificity of CAR T cells are urgently needed. Based on the observation that many human solid tumors activate epidermal growth factor receptor (EGFR) on their surface through secretion of EGFR ligands, we developed an engineering strategy for CAR-binding domains specifically directed against the ligand-activated conformation of EGFR. We show, in several experimental systems, that the generated binding domains indeed enable CAR T cells to distinguish between active and inactive EGFR. We anticipate that this engineering concept will be an important step forward to improve the tumor specificity of CAR T cells directed against EGFR-positive solid cancers.
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Affiliation(s)
- Markus Dobersberger
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria
| | - Delia Sumesgutner
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria
| | - Charlotte U Zajc
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria
| | - Benjamin Salzer
- CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria; St. Anna Children's Cancer Research Institute, CCRI, 1090 Vienna, Austria
| | - Elisabeth Laurent
- BOKU Core Facility Biomolecular & Cellular Analysis, BOKU University, 1190 Vienna, Austria
| | - Dominik Emminger
- CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria; St. Anna Children's Cancer Research Institute, CCRI, 1090 Vienna, Austria
| | - Elise Sylvander
- CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria; St. Anna Children's Cancer Research Institute, CCRI, 1090 Vienna, Austria
| | - Elisabeth Lehner
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria
| | - Magdalena Teufl
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria
| | - Jacqueline Seigner
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; Department of Biotechnology, Institute of Animal Cell Technology and Systems Biology, BOKU University, 1190 Vienna, Austria
| | - Madhusudhan Reddy Bobbili
- Department of Biotechnology, Institute of Molecular Biotechnology, BOKU University, 1190 Vienna, Austria; Ludwig Boltzmann Institute for Traumatology, Research Center in Cooperation with AUVA, 1200 Vienna, Austria
| | - Renate Kunert
- Department of Biotechnology, Institute of Animal Cell Technology and Systems Biology, BOKU University, 1190 Vienna, Austria
| | - Manfred Lehner
- CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria; St. Anna Children's Cancer Research Institute, CCRI, 1090 Vienna, Austria; St. Anna Children's Hospital, Department of Pediatrics, Medical University of Vienna, 1090 Vienna, Austria
| | - Michael W Traxlmayr
- Department of Chemistry, Institute of Biochemistry, BOKU University, 1190 Vienna, Austria; CD Laboratory for Next Generation CAR T Cells, 1090 Vienna, Austria.
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3
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Gentile R, Modric M, Thiele B, Jaeger KE, Kovacic F, Schott-Verdugo S, Gohlke H. Molecular Mechanisms Underlying Medium-Chain Free Fatty Acid-Regulated Activity of the Phospholipase PlaF from Pseudomonas aeruginosa. JACS AU 2024; 4:958-973. [PMID: 38559719 PMCID: PMC10976570 DOI: 10.1021/jacsau.3c00725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 04/04/2024]
Abstract
PlaF is a membrane-bound phospholipase A1 from Pseudomonas aeruginosa that is involved in remodeling membrane glycerophospholipids (GPLs) and modulating virulence-associated signaling and metabolic pathways. Previously, we identified the role of medium-chain free fatty acids (FFAs) in inhibiting PlaF activity and promoting homodimerization, yet the underlying molecular mechanism remained elusive. Here, we used unbiased and biased molecular dynamics simulations and free energy computations to assess how PlaF interacts with FFAs localized in the water milieu surrounding the bilayer or within the bilayer and how these interactions regulate PlaF activity. Medium-chain FFAs localized in the upper bilayer leaflet can stabilize inactive dimeric PlaF, likely through interactions with charged surface residues, as has been experimentally validated. Potential of mean force (PMF) computations indicate that membrane-bound FFAs may facilitate the activation of monomeric PlaF by lowering the activation barrier for changing into a tilted, active configuration. We estimated that the coupled equilibria of PlaF monomerization-dimerization and tilting at the physiological concentration of PlaF lead to the majority of PlaF forming inactive dimers when in a cell membrane loaded with decanoic acid (C10). This is in agreement with a suggested in vivo product feedback loop and gas chromatography-mass spectrometry profiling results, indicating that PlaF catalyzes the release of C10 from P. aeruginosa membranes. Additionally, we found that C10 in the water milieu can access the catalytic site of active monomeric PlaF, contributing to the competitive component of C10-mediated PlaF inhibition. Our study provides mechanistic insights into how medium-chain FFAs may regulate the activity of PlaF, a potential bacterial drug target.
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Affiliation(s)
- Rocco Gentile
- Institute
for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Matea Modric
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Björn Thiele
- Institute
of Bio- and Geosciences (IBG-2: Plant Sciences and IBG-3: Agrosphere), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Karl-Erich Jaeger
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
- Institute
of Bio- and Geosciences (IBG-1: Biotechnology), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Filip Kovacic
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Stephan Schott-Verdugo
- Institute
of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Holger Gohlke
- Institute
for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- Institute
of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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4
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Huang J, Xie X, Zheng W, Xu L, Yan J, Wu Y, Yang M, Yan Y. In silico design of multipoint mutants for enhanced performance of Thermomyces lanuginosus lipase for efficient biodiesel production. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:33. [PMID: 38402206 PMCID: PMC10894483 DOI: 10.1186/s13068-024-02478-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/15/2024] [Indexed: 02/26/2024]
Abstract
BACKGROUND Biodiesel, an emerging sustainable and renewable clean energy, has garnered considerable attention as an alternative to fossil fuels. Although lipases are promising catalysts for biodiesel production, their efficiency in industrial-scale application still requires improvement. RESULTS In this study, a novel strategy for multi-site mutagenesis in the binding pocket was developed via FuncLib (for mutant enzyme design) and Rosetta Cartesian_ddg (for free energy calculation) to improve the reaction rate and yield of lipase-catalyzed biodiesel production. Thermomyces lanuginosus lipase (TLL) with high activity and thermostability was obtained using the Pichia pastoris expression system. The specific activities of the mutants M11 and M21 (each with 5 and 4 mutations) were 1.50- and 3.10-fold higher, respectively, than those of the wild-type (wt-TLL). Their corresponding melting temperature profiles increased by 10.53 and 6.01 °C, [Formula: see text] (the temperature at which the activity is reduced to 50% after 15 min incubation) increased from 60.88 to 68.46 °C and 66.30 °C, and the optimum temperatures shifted from 45 to 50 °C. After incubation in 60% methanol for 1 h, the mutants M11 and M21 retained more than 60% activity, and 45% higher activity than that of wt-TLL. Molecular dynamics simulations indicated that the increase in thermostability could be explained by reduced atomic fluctuation, and the improved catalytic properties were attributed to a reduced binding free energy and newly formed hydrophobic interaction. Yields of biodiesel production catalyzed by mutants M11 and M21 for 48 h at an elevated temperature (50 °C) were 94.03% and 98.56%, respectively, markedly higher than that of the wt-TLL (88.56%) at its optimal temperature (45 °C) by transesterification of soybean oil. CONCLUSIONS An integrating strategy was first adopted to realize the co-evolution of catalytic efficiency and thermostability of lipase. Two promising mutants M11 and M21 with excellent properties exhibited great potential for practical applications for in biodiesel production.
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Affiliation(s)
- Jinsha Huang
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiaoman Xie
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wanlin Zheng
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Li Xu
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
| | - Jinyong Yan
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Ying Wu
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Min Yang
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yunjun Yan
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
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5
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Derbyshire MC, Raffaele S. Surface frustration re-patterning underlies the structural landscape and evolvability of fungal orphan candidate effectors. Nat Commun 2023; 14:5244. [PMID: 37640704 PMCID: PMC10462633 DOI: 10.1038/s41467-023-40949-9] [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: 01/10/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
Pathogens secrete effector proteins to subvert host physiology and cause disease. Effectors are engaged in a molecular arms race with the host resulting in conflicting evolutionary constraints to manipulate host cells without triggering immune responses. The molecular mechanisms allowing effectors to be at the same time robust and evolvable remain largely enigmatic. Here, we show that 62 conserved structure-related families encompass the majority of fungal orphan effector candidates in the Pezizomycotina subphylum. These effectors diversified through changes in patterns of thermodynamic frustration at surface residues. The underlying mutations tended to increase the robustness of the overall effector protein structure while switching potential binding interfaces. This mechanism could explain how conserved effector families maintained biological activity over long evolutionary timespans in different host environments and provides a model for the emergence of sequence-unrelated effector families with conserved structures.
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Affiliation(s)
- Mark C Derbyshire
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes Micro-organismes Environnement (LIPME), INRAE, CNRS, Université de Toulouse, 31326, Castanet-Tolosan, France.
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6
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Anderson DM, Jayanthi LP, Gosavi S, Meiering EM. Engineering the kinetic stability of a β-trefoil protein by tuning its topological complexity. Front Mol Biosci 2023; 10:1021733. [PMID: 36845544 PMCID: PMC9945329 DOI: 10.3389/fmolb.2023.1021733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/02/2023] [Indexed: 02/11/2023] Open
Abstract
Kinetic stability, defined as the rate of protein unfolding, is central to determining the functional lifetime of proteins, both in nature and in wide-ranging medical and biotechnological applications. Further, high kinetic stability is generally correlated with high resistance against chemical and thermal denaturation, as well as proteolytic degradation. Despite its significance, specific mechanisms governing kinetic stability remain largely unknown, and few studies address the rational design of kinetic stability. Here, we describe a method for designing protein kinetic stability that uses protein long-range order, absolute contact order, and simulated free energy barriers of unfolding to quantitatively analyze and predict unfolding kinetics. We analyze two β-trefoil proteins: hisactophilin, a quasi-three-fold symmetric natural protein with moderate stability, and ThreeFoil, a designed three-fold symmetric protein with extremely high kinetic stability. The quantitative analysis identifies marked differences in long-range interactions across the protein hydrophobic cores that partially account for the differences in kinetic stability. Swapping the core interactions of ThreeFoil into hisactophilin increases kinetic stability with close agreement between predicted and experimentally measured unfolding rates. These results demonstrate the predictive power of readily applied measures of protein topology for altering kinetic stability and recommend core engineering as a tractable target for rationally designing kinetic stability that may be widely applicable.
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Affiliation(s)
| | - Lakshmi P. Jayanthi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Elizabeth M. Meiering
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada,*Correspondence: Elizabeth M. Meiering,
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7
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Alteration of Chain-Length Selectivity and Thermostability of Rhizopus oryzae Lipase via Virtual Saturation Mutagenesis Coupled with Disulfide Bond Design. Appl Environ Microbiol 2023; 89:e0187822. [PMID: 36602359 PMCID: PMC9888275 DOI: 10.1128/aem.01878-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Rhizopus oryzae lipase (ROL) is one of the most important enzymes used in the food, biofuel, and pharmaceutical industries. However, the highly demanding conditions of industrial processes can reduce its stability and activity. To seek a feasible method to improve both the catalytic activity and the thermostability of this lipase, first, the structure of ROL was divided into catalytic and noncatalytic regions by identifying critical amino acids in the crevice-like binding pocket. Second, a mutant screening library aimed at improvement of ROL catalytic performance by virtual saturation mutagenesis of residues in the catalytic region was constructed based on Rosetta's Cartesian_ddg protocol. A double mutant, E265V/S267W (with an E-to-V change at residue 265 and an S-to-W change at residue 267), with markedly improved catalytic activity toward diverse chain-length fatty acid esters was identified. Then, computational design of disulfide bonds was conducted for the noncatalytic amino acids of E265V/S267W, and two potential disulfide bonds, S61C-S115C and E190C-E238C, were identified as candidates. Experimental data validated that the variant E265V/S267W/S61C-S115C/E190C-E238C had superior stability, with an increase of 8.5°C in the melting temperature and a half-life of 31.7 min at 60°C, 4.2-fold longer than that of the wild-type enzyme. Moreover, the variant improved the lipase activity toward five 4-nitrophenyl esters by 1.5 to 3.8 times, exhibiting a potential to modify the catalytic efficiency. IMPORTANCE Rhizopus oryzae lipase (ROL) is very attractive in biotechnology and industry as a safe and environmentally friendly biocatalyst. Functional expression of ROL in Escherichia coli facilitates effective high-throughput screening for positive variants. This work highlights a method to improve both selectivity and thermostability based on a combination of virtual saturation mutagenesis in the substrate pocket and disulfide bond prediction in the noncatalytic region. Using the method, ROL thermostability and activity to diverse 4-nitrophenyl esters could be substantially improved. The strategy of rational introduction of multiple mutations in different functional domains of the enzyme is a great prospect in the modification of biocatalysts.
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8
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Krishnani KK, Oakeshott JG, Pandey G. Wide substrate range for a candidate bioremediation enzyme isolated from Nocardioides sp. strain SG-4 G. FEMS Microbiol Lett 2023; 370:fnad085. [PMID: 37660276 PMCID: PMC10501498 DOI: 10.1093/femsle/fnad085] [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: 07/04/2023] [Revised: 08/09/2023] [Accepted: 08/25/2023] [Indexed: 09/04/2023] Open
Abstract
Narrow substrate ranges can impact heavily on the range of applications and hence commercial viability of candidate bioremediation enzymes. Here we show that an ester hydrolase from Nocardioides strain SG-4 G has potential as a bioremediation agent against various pollutants that can be detoxified by hydrolytic cleavage of some carboxylester, carbamate, or amide linkages. Previously we showed that a radiation-killed, freeze-dried preparation (ZimA) of this strain can rapidly degrade the benzimidazole fungicide carbendazim due to the activity of a specific ester hydrolase, MheI. Here, we report that ZimA also has substantial hydrolytic activity against phthalate diesters (dimethyl, dibutyl, and dioctyl phthalate), anilide (propanil and monalide), and carbamate ester (chlorpropham) herbicides under laboratory conditions. The reaction products are substantially less toxic, or inactive as herbicides, than the parent compounds. Tests of strain SG-4 G and Escherichia coli expressing MheI found they were also able to hydrolyse dimethyl phthalate, propanil, and chlorpropham, indicating that MheI is principally responsible for the above activities.
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Affiliation(s)
- Kishore K Krishnani
- CSIRO Environment, Canberra, ACT 2601, Australia
- Central Institute of Fisheries Education, Versova, Andheri (West), Mumbai 400061, India
| | - John G Oakeshott
- CSIRO Environment, Canberra, ACT 2601, Australia
- Applied BioSciences, Macquarie University, North Ryde, New South Wales 2113, Australia
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9
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Aledo P, Aledo JC. Proteome-Wide Structural Computations Provide Insights into Empirical Amino Acid Substitution Matrices. Int J Mol Sci 2023; 24:ijms24010796. [PMID: 36614247 PMCID: PMC9821064 DOI: 10.3390/ijms24010796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
The relative contribution of mutation and selection to the amino acid substitution rates observed in empirical matrices is unclear. Herein, we present a neutral continuous fitness-stability model, inspired by the Arrhenius law (qij=aije-ΔΔGij). The model postulates that the rate of amino acid substitution (i→j) is determined by the product of a pre-exponential factor, which is influenced by the genetic code structure, and an exponential term reflecting the relative fitness of the amino acid substitutions. To assess the validity of our model, we computed changes in stability of 14,094 proteins, for which 137,073,638 in silico mutants were analyzed. These site-specific data were summarized into a 20 square matrix, whose entries, ΔΔGij, were obtained after averaging through all the sites in all the proteins. We found a significant positive correlation between these energy values and the disease-causing potential of each substitution, suggesting that the exponential term accurately summarizes the fitness effect. A remarkable observation was that amino acids that were highly destabilizing when acting as the source, tended to have little effect when acting as the destination, and vice versa (source → destination). The Arrhenius model accurately reproduced the pattern of substitution rates collected in the empirical matrices, suggesting a relevant role for the genetic code structure and a tuning role for purifying selection exerted via protein stability.
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10
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Abstract
Yeast surface display is a powerful protein engineering technology that is extensively used to improve various properties of proteins, including affinity, specificity, and stability or even to add novel functions (usually ligand binding). Apart from its robustness and versatility as an engineering tool, yeast display offers a further critical advantage: Once the selection campaign is finished, usually resulting in an oligoclonal pool, these enriched protein variants can be analyzed individually on the surface of yeast without the need for any sub-cloning, soluble expression, and purification. Here, we provide detailed protocols for determining both the affinity and the thermal stability of yeast displayed proteins. In addition, we discuss the advantages, challenges, and potential pitfalls associated with affinity and stability analysis using yeast surface display.
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Affiliation(s)
- Charlotte U Zajc
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
- CD Laboratory for Next Generation CAR T Cells, Vienna, Austria
| | - Magdalena Teufl
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
- CD Laboratory for Next Generation CAR T Cells, Vienna, Austria
| | - Michael W Traxlmayr
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria.
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