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Zhang Y, Li J, Pang Y, Shu Y, Liu S, Sang P, Sun X, Liu J, Yang Y, Chen M, Hong P. Systematic investigation of simultaneous copper biosorption and nitrogen removal from wastewater by an aerobic denitrifying bacterium of auto-aggregation. ENVIRONMENTAL RESEARCH 2023; 235:116602. [PMID: 37429397 DOI: 10.1016/j.envres.2023.116602] [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: 05/13/2023] [Revised: 07/02/2023] [Accepted: 07/07/2023] [Indexed: 07/12/2023]
Abstract
Finding effective methods for simultaneous removal of eutrophic nutrients and heavy metals has attracted increasing concerns for the environmental remediation. Herein, a novel auto-aggregating aerobic denitrifying strain (Aeromonas veronii YL-41) was isolated with capacities for copper tolerance and biosorption. The denitrification efficiency and nitrogen removal pathway of the strain were investigated by nitrogen balance analysis and amplification of key denitrification functional genes. Moreover, the changes in the auto-aggregation properties of the strain caused by extracellular polymeric substances (EPS) production were focused on. The biosorption capacity and mechanisms of copper tolerance during denitrification were further explored by measuring changes in copper tolerance and adsorption indices, as well as by variations in extracellular functional groups. The strain showed extremely strong total nitrogen removal ability, with 67.5%, 82.08% and 78.48% of total nitrogen removal when NH4+-N, NO2--N, and NO3--N were used as the only initial nitrogen source, respectively. The successful amplification of napA, nirK, norR, and nosZ genes further demonstrated that the strain accomplished nitrate removal through a complete aerobic denitrification pathway. The production of protein-rich EPS of up to 23.31 mg/g and an auto-aggregation index of up to 76.42% may confer a strong biofilm-forming potential to the strain. Under the stress of 20 mg/L copper ions, the removal of nitrate-nitrogen was still as high as 71.4%. In addition, the strain could achieve an efficient removal of 96.9% of copper ions at an initial concentration of 80 mg/L. Scanning electron microscopy and deconvolution analysis of characteristic peaks confirmed that the strains encapsulate heavy metals by secreting EPS and, meanwhile, form strong hydrogen bonding structures to enhance intermolecular forces to resist copper ion stress. This study provides an innovative and effective biological approach for the synergistic bioaugmentation removal of eutrophic substances and heavy metals from aquatic environments.
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Affiliation(s)
- Yancheng Zhang
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Jing Li
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Yu Pang
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Yilin Shu
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Shu Liu
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Pengcheng Sang
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Xiaohui Sun
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Jiexiu Liu
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Yanfang Yang
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China
| | - Minglin Chen
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China.
| | - Pei Hong
- College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China.
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2
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Flynn AJ, Antonyuk SV, Eady RR, Muench SP, Hasnain SS. A 2.2 Å cryoEM structure of a quinol-dependent NO Reductase shows close similarity to respiratory oxidases. Nat Commun 2023; 14:3416. [PMID: 37296134 PMCID: PMC10256718 DOI: 10.1038/s41467-023-39140-x] [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: 11/25/2022] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Quinol-dependent nitric oxide reductases (qNORs) are considered members of the respiratory heme-copper oxidase superfamily, are unique to bacteria, and are commonly found in pathogenic bacteria where they play a role in combating the host immune response. qNORs are also essential enzymes in the denitrification pathway, catalysing the reduction of nitric oxide to nitrous oxide. Here, we determine a 2.2 Å cryoEM structure of qNOR from Alcaligenes xylosoxidans, an opportunistic pathogen and a denitrifying bacterium of importance in the nitrogen cycle. This high-resolution structure provides insight into electron, substrate, and proton pathways, and provides evidence that the quinol binding site not only contains the conserved His and Asp residues but also possesses a critical Arg (Arg720) observed in cytochrome bo3, a respiratory quinol oxidase.
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Affiliation(s)
- Alex J Flynn
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Svetlana V Antonyuk
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, England
| | - Robert R Eady
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, England
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - S Samar Hasnain
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, England.
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3
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Lycus P, Einsle O, Zhang L. Structural biology of proteins involved in nitrogen cycling. Curr Opin Chem Biol 2023; 74:102278. [PMID: 36889028 DOI: 10.1016/j.cbpa.2023.102278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 03/08/2023]
Abstract
Microbial metabolic processes drive the global nitrogen cycle through sophisticated and often unique metalloenzymes that facilitate difficult redox reactions at ambient temperature and pressure. Understanding the intricacies of these biological nitrogen transformations requires a detailed knowledge that arises from the combination of a multitude of powerful analytical techniques and functional assays. Recent developments in spectroscopy and structural biology have provided new, powerful tools for addressing existing and emerging questions, which have gained urgency due to the global environmental implications of these fundamental reactions. The present review focuses on the recent contributions of the wider area of structural biology to understanding nitrogen metabolism, opening new avenues for biotechnological applications to better manage and balance the challenges of the global nitrogen cycle.
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Affiliation(s)
- Pawel Lycus
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany; Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany.
| | - Lin Zhang
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany.
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4
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Gopalasingam CC, Hasnain SS. Frontiers in metalloprotein crystallography and cryogenic electron microscopy. Curr Opin Struct Biol 2022; 75:102420. [PMID: 35841747 DOI: 10.1016/j.sbi.2022.102420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 11/03/2022]
Abstract
Metalloproteins comprise at least a third of all proteins that utilize redox properties of transition metals on their own or as parts of cofactors. The development of third generation storage ring sources and X-ray free-electron lasers with femtosecond pulses in the first decade of the 21st century has transformed metalloprotein crystallography. In the past decade, cryogenic-electron microscopy single-particle analysis, which does not require crystallization of biological samples has been extensively utilized, particularly for membrane-bound metalloprotein systems. Here, we explore recent frontiers in metalloprotein crystallography and cryogenic electron microscopy, organized for convenience under three metalloprotein-centered biological cycles, focusing on contributions from each technique, their synergy and the ability to preserve metals' redox states when subjected to a particular probe.
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Affiliation(s)
- Chai C Gopalasingam
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK; Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo, 678-1297, Japan. https://twitter.com/@Chai_Gopal
| | - S Samar Hasnain
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK.
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5
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He HY, Niikura H, Du YL, Ryan KS. Synthetic and biosynthetic routes to nitrogen-nitrogen bonds. Chem Soc Rev 2022; 51:2991-3046. [PMID: 35311838 DOI: 10.1039/c7cs00458c] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The nitrogen-nitrogen bond is a core feature of diverse functional groups like hydrazines, nitrosamines, diazos, and pyrazoles. Such functional groups are found in >300 known natural products. Such N-N bond-containing functional groups are also found in significant percentage of clinical drugs. Therefore, there is wide interest in synthetic and enzymatic methods to form nitrogen-nitrogen bonds. In this review, we summarize synthetic and biosynthetic approaches to diverse nitrogen-nitrogen-bond-containing functional groups, with a focus on biosynthetic pathways and enzymes.
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Affiliation(s)
- Hai-Yan He
- Department of Chemistry, University of British Columbia, Vancouver, Canada. .,Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
| | - Haruka Niikura
- Department of Chemistry, University of British Columbia, Vancouver, Canada.
| | - Yi-Ling Du
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
| | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, Canada.
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6
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Shinzawa-Itoh K, Muramoto K. Biochemical and crystallographic studies of monomeric and dimeric bovine cytochrome c oxidase. Biophys Physicobiol 2021; 18:186-195. [PMID: 34513548 PMCID: PMC8390318 DOI: 10.2142/biophysico.bppb-v18.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/13/2021] [Indexed: 12/01/2022] Open
Abstract
Cytochrome c oxidase (CcO), a terminal oxidase in the respiratory chain, catalyzes the reduction of O2 to water coupled with the proton pump across the membrane. Mitochondrial CcO exists in monomeric and dimeric forms, and as a monomer as part of the respiratory supercomplex, although the enzymatic reaction proceeds in the CcO monomer. Recent biochemical and crystallographic studies of monomeric and dimeric CcOs have revealed functional and structural differences among them. In solubilized mitochondrial membrane, the monomeric form is dominant, and a small amount of dimer is observed. The activity of the monomeric CcO is higher than that of the dimer, suggesting that the monomer is the active form. In the structure of monomeric CcO, a hydrogen bond network of water molecules is formed at the entrance of the proton transfer K-pathway, and in dimeric CcO, this network is altered by a cholate molecule binding between monomers. The specific binding of the cholate molecule at the dimer interface suggests that the binding of physiological ligands similar in size or shape to cholate could also trigger dimer formation as a physiological standby form. Because the dimer interface also contains weak interactions of nonspecifically bound lipid molecules, hydrophobic interactions between the transmembrane helices, and a Met-Met interaction between the extramembrane regions, these interactions could support the stabilization of the standby form. Structural analyses also suggest that hydrophobic interactions of cardiolipins bound to the trans-membrane surface of CcO are involved in forming the supercomplex.
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Affiliation(s)
- Kyoko Shinzawa-Itoh
- Graduate School of Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Kazumasa Muramoto
- Graduate School of Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
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7
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Amphipathic environments for determining the structure of membrane proteins by single-particle electron cryo-microscopy. Q Rev Biophys 2021; 54:e6. [PMID: 33785082 DOI: 10.1017/s0033583521000044] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Over the past decade, the structural biology of membrane proteins (MPs) has taken a new turn thanks to epoch-making technical progress in single-particle electron cryo-microscopy (cryo-EM) as well as to improvements in sample preparation. The present analysis provides an overview of the extent and modes of usage of the various types of surfactants for cryo-EM studies. Digitonin, dodecylmaltoside, protein-based nanodiscs, lauryl maltoside-neopentyl glycol, glyco-diosgenin, and amphipols (APols) are the most popular surfactants at the vitrification step. Surfactant exchange is frequently used between MP purification and grid preparation, requiring extensive optimization each time the study of a new MP is undertaken. The variety of both the surfactants and experimental approaches used over the past few years bears witness to the need to continue developing innovative surfactants and optimizing conditions for sample preparation. The possibilities offered by novel APols for EM applications are discussed.
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8
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Reed CJ, Lam QN, Mirts EN, Lu Y. Molecular understanding of heteronuclear active sites in heme-copper oxidases, nitric oxide reductases, and sulfite reductases through biomimetic modelling. Chem Soc Rev 2021; 50:2486-2539. [PMID: 33475096 PMCID: PMC7920998 DOI: 10.1039/d0cs01297a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Heme-copper oxidases (HCO), nitric oxide reductases (NOR), and sulfite reductases (SiR) catalyze the multi-electron and multi-proton reductions of O2, NO, and SO32-, respectively. Each of these reactions is important to drive cellular energy production through respiratory metabolism and HCO, NOR, and SiR evolved to contain heteronuclear active sites containing heme/copper, heme/nonheme iron, and heme-[4Fe-4S] centers, respectively. The complexity of the structures and reactions of these native enzymes, along with their large sizes and/or membrane associations, make it challenging to fully understand the crucial structural features responsible for the catalytic properties of these active sites. In this review, we summarize progress that has been made to better understand these heteronuclear metalloenzymes at the molecular level though study of the native enzymes along with insights gained from biomimetic models comprising either small molecules or proteins. Further understanding the reaction selectivity of these enzymes is discussed through comparisons of their similar heteronuclear active sites, and we offer outlook for further investigations.
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Affiliation(s)
- Christopher J Reed
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA.
| | - Quan N Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA
| | - Evan N Mirts
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA. and Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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9
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Tosha T, Yamagiwa R, Sawai H, Shiro Y. NO Dynamics in Microbial Denitrification System. CHEM LETT 2021. [DOI: 10.1246/cl.200629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Takehiko Tosha
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Raika Yamagiwa
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hitomi Sawai
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
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10
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Chojnowski G, Sobolev E, Heuser P, Lamzin VS. The accuracy of protein models automatically built into cryo-EM maps with ARP/wARP. Acta Crystallogr D Struct Biol 2021; 77:142-150. [PMID: 33559604 PMCID: PMC7869898 DOI: 10.1107/s2059798320016332] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/16/2020] [Indexed: 11/26/2022] Open
Abstract
A new module of the ARP/wARP suite for automated model building into cryo-EM maps is presented. Recent developments in cryogenic electron microscopy (cryo-EM) have enabled structural studies of large macromolecular complexes at resolutions previously only attainable using macromolecular crystallography. Although a number of methods can already assist in de novo building of models into high-resolution cryo-EM maps, automated and reliable map interpretation remains a challenge. Presented here is a systematic study of the accuracy of models built into cryo-EM maps using ARP/wARP. It is demonstrated that the local resolution is a good indicator of map interpretability, and for the majority of the test cases ARP/wARP correctly builds 90% of main-chain fragments in regions where the local resolution is 4.0 Å or better. It is also demonstrated that the coordinate accuracy for models built into cryo-EM maps is comparable to that of X-ray crystallographic models at similar local cryo-EM and crystallographic resolutions. The model accuracy also correlates with the refined atomic displacement parameters.
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Affiliation(s)
- Grzegorz Chojnowski
- European Molecular Biology Laboratory, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Egor Sobolev
- European Molecular Biology Laboratory, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Philipp Heuser
- European Molecular Biology Laboratory, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Victor S Lamzin
- European Molecular Biology Laboratory, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
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11
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Jamali MAM, Gopalasingam CC, Johnson RM, Tosha T, Muramoto K, Muench SP, Antonyuk SV, Shiro Y, Hasnain SS. The active form of quinol-dependent nitric oxide reductase from Neisseria meningitidis is a dimer. IUCRJ 2020; 7:404-415. [PMID: 32431824 PMCID: PMC7201271 DOI: 10.1107/s2052252520003656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/11/2020] [Indexed: 06/11/2023]
Abstract
Neisseria meningitidis is carried by nearly a billion humans, causing developmental impairment and over 100 000 deaths a year. A quinol-dependent nitric oxide reductase (qNOR) plays a critical role in the survival of the bacterium in the human host. X-ray crystallographic analyses of qNOR, including that from N. meningitidis (NmqNOR) reported here at 3.15 Å resolution, show monomeric assemblies, despite the more active dimeric sample being used for crystallization. Cryo-electron microscopic analysis of the same chromatographic fraction of NmqNOR, however, revealed a dimeric assembly at 3.06 Å resolution. It is shown that zinc (which is used in crystallization) binding near the dimer-stabilizing TMII region contributes to the disruption of the dimer. A similar destabilization is observed in the monomeric (∼85 kDa) cryo-EM structure of a mutant (Glu494Ala) qNOR from the opportunistic pathogen Alcaligenes (Achromobacter) xylosoxidans, which primarily migrates as a monomer. The monomer-dimer transition of qNORs seen in the cryo-EM and crystallographic structures has wider implications for structural studies of multimeric membrane proteins. X-ray crystallographic and cryo-EM structural analyses have been performed on the same chromatographic fraction of NmqNOR to high resolution. This represents one of the first examples in which the two approaches have been used to reveal a monomeric assembly in crystallo and a dimeric assembly in vitrified cryo-EM grids. A number of factors have been identified that may trigger the destabilization of helices that are necessary to preserve the integrity of the dimer. These include zinc binding near the entry of the putative proton-transfer channel and the preservation of the conformational integrity of the active site. The mutation near the active site results in disruption of the active site, causing an additional destabilization of helices (TMIX and TMX) that flank the proton-transfer channel helices, creating an inert monomeric enzyme.
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Affiliation(s)
- M. Arif M. Jamali
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Chai C. Gopalasingam
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Rachel M. Johnson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Takehiko Tosha
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Kazumasa Muramoto
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Stephen P. Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Samar S. Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
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12
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Yamato T, Leitner DM. Structure, dynamics, and energy flow that govern Heme protein functions: theory and experiments. Session 3SBA at the 57th BSJ Annual Meeting. Biophys Rev 2020; 12:291-292. [PMID: 32002759 DOI: 10.1007/s12551-020-00625-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/14/2020] [Indexed: 10/25/2022] Open
Affiliation(s)
- Takahisa Yamato
- Division of Material Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
| | - David M Leitner
- Division of Material Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.,Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, NV, 89557, USA
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