1
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Wang Z, Chu Y, Li Q, Han X, Zhao L, Zhang H, Cai K, Zhang X, Wang X, Qin Y, Fan E. A minimum functional form of the Escherichia coli BAM complex constituted by BamADE assembles outer membrane proteins in vitro. J Biol Chem 2024; 300:107324. [PMID: 38677515 PMCID: PMC11130730 DOI: 10.1016/j.jbc.2024.107324] [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: 04/03/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024] Open
Abstract
The biogenesis of outer membrane proteins is mediated by the β-barrel assembly machinery (BAM), which is a heteropentomeric complex composed of five proteins named BamA-E in Escherichia coli. Despite great progress in the BAM structural analysis, the molecular details of BAM-mediated processes as well as the exact function of each BAM component during OMP assembly are still not fully understood. To enable a distinguishment of the function of each BAM component, it is the aim of the present work to examine and identify the effective minimum form of the E. coli BAM complex by use of a well-defined reconstitution strategy based on a previously developed versatile assay. Our data demonstrate that BamADE is the core BAM component and constitutes a minimum functional form for OMP assembly in E. coli, which can be stimulated by BamB and BamC. While BamB and BamC have a redundant function based on the minimum form, both together seem to cooperate with each other to substitute for the function of the missing BamD or BamE. Moreover, the BamAE470K mutant also requires the function of BamD and BamE to assemble OMPs in vitro, which vice verse suggests that BamADE are the effective minimum functional form of the E. coli BAM complex.
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Affiliation(s)
- Zhe Wang
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Yindi Chu
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Qingrong Li
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Xiaochen Han
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Leyi Zhao
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Hanqing Zhang
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Kun Cai
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Xuyan Zhang
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Xingyuan Wang
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Youcai Qin
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Enguo Fan
- Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China; School of Medicine, Linyi University, Linyi, China.
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2
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Herwig S, Kleinschmidt JH. The Formation of β-Strand Nine ( β9) in the Folding and Insertion of BamA from an Unfolded Form into Lipid Bilayers. MEMBRANES 2023; 13:247. [PMID: 36837750 PMCID: PMC9964827 DOI: 10.3390/membranes13020247] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Transmembrane proteins span lipid bilayer membranes and serve essential functions in all living cells. Membrane-inserted domains are of either α-helical or β-barrel structure. Despite their biological importance, the biophysical mechanisms of the folding and insertion of proteins into membranes are not well understood. While the relative composition of the secondary structure has been examined by circular dichroism spectroscopy in folding studies for several outer membrane proteins, it is currently not known how individual β-strands fold. Here, the folding and insertion of the β-barrel assembly machinery protein A (BamA) from the outer membrane of Escherichia coli into lipid bilayers were investigated, and the formation of strand nine (β9) of BamA was examined. Eight single-cysteine mutants of BamA were overexpressed and isolated in unfolded form in 8 M urea. In each of these mutants, one of the residues of strand β9, from R572 to V579, was replaced by a cysteine and labeled with the fluorophore IAEDANS for site-directed fluorescence spectroscopy. Upon urea-dilution, the mutants folded into the native structure and were inserted into lipid bilayers of dilauroylphosphatidylcholine, similar to wild-type BamA. An aqueous and a membrane-adsorbed folding intermediate of BamA could be identified by strong shifts in the intensity maxima of the IAEDANS fluorescence of the labeled mutants of BamA towards shorter wavelengths, even in the absence of lipid bilayers. The shifts were greatest for membrane-adsorbed mutants and smaller for the inserted, folded mutants or the aqueous intermediates. The spectra of the mutants V573C-, L575C-, G577C-, and V579C-BamA, facing the lipid bilayer, displayed stronger shifts than the spectra recorded for the mutants R572C-, N574C-, T576C-, and K578C-BamA, facing the β-barrel lumen, in both the membrane-adsorbed form and the folded, inserted form. This alternating pattern was neither observed for the IAEDANS spectra of the unfolded forms nor for the water-collapsed forms, indicating that strand β9 forms in a membrane-adsorbed folding intermediate of BamA. The combination of cysteine scanning mutagenesis and site-directed fluorescence labeling is shown to be a valuable tool in examining the local secondary structure formation of transmembrane proteins.
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Affiliation(s)
- Sascha Herwig
- Institut für Biologie, FB 10 Mathematik und Naturwissenschaften, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
| | - Jörg H. Kleinschmidt
- Institut für Biologie, FB 10 Mathematik und Naturwissenschaften, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
- Center of Interdisciplinary Nanostructure Science and Technology, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
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3
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Zhang Z, Ryoo D, Balusek C, Acharya A, Rydmark MO, Linke D, Gumbart JC. Inward-facing glycine residues create sharp turns in β-barrel membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183662. [PMID: 34097860 DOI: 10.1016/j.bbamem.2021.183662] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 04/15/2021] [Accepted: 05/17/2021] [Indexed: 11/29/2022]
Abstract
The transmembrane region of outer-membrane proteins (OMPs) of Gram-negative bacteria are almost exclusively β-barrels composed of between 8 and 26 β-strands. To explore the relationship between β-barrel size and shape, we modeled and simulated engineered variants of the Escherichia coli protein OmpX with 8, 10, 12, 14, and 16 β-strands. We found that while smaller barrels maintained a roughly circular shape, the 16-stranded variant developed a flattened cross section. This flat cross section impeded its ability to conduct ions, in agreement with previous experimental observations. Flattening was determined to arise from the presence of inward-facing glycines at sharp turns in the β-barrel. An analysis of all simulations revealed that glycines, on average, make significantly smaller angles with residues on neighboring strands than all other amino acids, including alanine, and create sharp turns in β-barrel cross sections. This observation was generalized to 119 unique structurally resolved OMPs. We also found that the fraction of glycines in β-barrels decreases as the strand number increases, suggesting an evolutionary role for the addition or removal of glycine in OMP sequences.
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Affiliation(s)
- Zijian Zhang
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America
| | - David Ryoo
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
| | - Curtis Balusek
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America
| | - Atanu Acharya
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America
| | | | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America.
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4
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Chu Y, Wang Z, Weigold S, Norrell D, Fan E. TtOmp85, a single Omp85 member protein functions as a β-barrel protein insertase and an autotransporter translocase without any accessory proteins. Biochem Biophys Res Commun 2021; 552:73-77. [PMID: 33743350 DOI: 10.1016/j.bbrc.2021.03.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
The biogenesis of outer membrane proteins requires the function of β-barrel assembly machinery (BAM), whose function is highly conserved while its composition is variable. The Escherichia coli BAM is composed of five subunits, while Thermus thermophilus seems to contain a single BAM protein, named TtOmp85. To search for the primitive form of a functional BAM, we investigated and compared the function of TtOmp85 and E. coli BAM by use of a reconstitution assay that examines the integration of OmpA and BamA from E. coli and TtoA from T. thermophilus, as well as the translocation of the E. coli Ag43. Our results show that a single TtOmp85 protein can substitute for the collective function of the five subunits constituting E. coli BAM.
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Affiliation(s)
- Yindi Chu
- State Key Laboratory of Medical Molecular Biology, Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Zhe Wang
- State Key Laboratory of Medical Molecular Biology, Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Sebastian Weigold
- Institute of Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, Stefan-Meier-Straße 17, 79104, Freiburg im Breisgau, Germany
| | - Derrick Norrell
- Institute of Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, Stefan-Meier-Straße 17, 79104, Freiburg im Breisgau, Germany
| | - Enguo Fan
- State Key Laboratory of Medical Molecular Biology, Department of Microbiology and Parasitology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China; Institute of Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, Stefan-Meier-Straße 17, 79104, Freiburg im Breisgau, Germany; College of Life Sciences, Linyi University, Linyi, 276005, China.
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5
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De Franceschi N, Miihkinen M, Hamidi H, Alanko J, Mai A, Picas L, Guzmán C, Lévy D, Mattjus P, Goult BT, Goud B, Ivaska J. ProLIF - quantitative integrin protein-protein interactions and synergistic membrane effects on proteoliposomes. J Cell Sci 2018; 132:jcs.214270. [PMID: 30072441 DOI: 10.1242/jcs.214270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 07/07/2018] [Indexed: 01/23/2023] Open
Abstract
Integrin transmembrane receptors control a wide range of biological interactions by triggering the assembly of large multiprotein complexes at their cytoplasmic interface. Diverse methods have been used to investigate interactions between integrins and intracellular proteins, and predominantly include peptide-based pulldowns and biochemical immuno-isolations from detergent-solubilised cell lysates. However, quantitative methods to probe integrin-protein interactions in a more biologically relevant context where the integrin is embedded within a lipid bilayer have been lacking. Here, we describe 'protein-liposome interactions by flow cytometry' (denoted ProLIF), a technique to reconstitute recombinant integrin transmembrane domains (TMDs) and cytoplasmic tail (CT) fragments in liposomes as individual subunits or as αβ heterodimers and, via flow cytometry, allow rapid and quantitative measurement of protein interactions with these membrane-embedded integrins. Importantly, the assay can analyse binding of fluorescent proteins directly from cell lysates without further purification steps. Moreover, the effect of membrane composition, such as PI(4,5)P2 incorporation, on protein recruitment to the integrin CTs can be analysed. ProLIF requires no specific instrumentation and can be applied to measure a broad range of membrane-dependent protein-protein interactions with the potential for high-throughput/multiplex analyses.This article has associated First Person interviews with the first authors of the paper (see doi: 10.1242/jcs.223644 and doi: 10.1242/jcs.223719).
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Affiliation(s)
- Nicola De Franceschi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland.,Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR 168, 75005 Paris, France.,Sorbonne Universités, UPMC, 75005 Paris, France
| | - Mitro Miihkinen
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Hellyeh Hamidi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Jonna Alanko
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Anja Mai
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Laura Picas
- Institut Curie, PSL Research University, UMR 168, Centre de Recherche, 75248 Paris, France
| | - Camilo Guzmán
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Daniel Lévy
- Institut Curie, PSL Research University, UMR 168, Centre de Recherche, 75248 Paris, France
| | - Peter Mattjus
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland
| | - Benjamin T Goult
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Bruno Goud
- Institut Curie, PSL Research University, UMR 168, Centre de Recherche, 75248 Paris, France
| | - Johanna Ivaska
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland .,Department of Biochemistry, University of Turku, 20520 Turku, Finland
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6
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Chaturvedi D, Mahalakshmi R. Folding Determinants of Transmembrane β-Barrels Using Engineered OMP Chimeras. Biochemistry 2018. [DOI: 10.1021/acs.biochem.8b00012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal − 462066, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal − 462066, India
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7
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A tamB homolog is involved in maintenance of cell envelope integrity and stress resistance of Deinococcus radiodurans. Sci Rep 2017; 7:45929. [PMID: 28383523 PMCID: PMC5382914 DOI: 10.1038/srep45929] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/06/2017] [Indexed: 12/21/2022] Open
Abstract
The translocation and assembly module (TAM) in bacteria consists of TamA and TamB that form a complex to control the transport and secretion of outer membrane proteins. Herein, we demonstrated that the DR_1462-DR_1461-DR_1460 gene loci on chromosome 1 of Deinococcus radiodurans, which lacks tamA homologs, is a tamB homolog (DR_146T) with two tamB motifs and a DUF490 motif. Mutation of DR_146T resulted in cell envelope peeling and a decrease in resistance to shear stress and osmotic pressure, as well as an increase in oxidative stress resistance, consistent with the phenotype of a surface layer (S-layer) protein SlpA (DR_2577) mutant, demonstrating the involvement of DR_146T in maintenance of cell envelope integrity. The 123 kDa SlpA was absent and only its fragments were present in the cell envelope of DR_146T mutant, suggesting that DR_146T might be involved in maintenance of the S-layer. A mutant lacking the DUF490 motif displayed only a slight alteration in phenotype compared with the wild type, suggesting DUF490 is less important than tamB motif for the function of DR_146T. These findings enhance our understanding of the properties of the multilayered envelope in extremophilic D. radiodurans, as well as the diversity and functions of TAMs in bacteria.
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8
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Henke K, Welte W, Hauser K. Direct Monitoring of β-Sheet Formation in the Outer Membrane Protein TtoA Assisted by TtOmp85. Biochemistry 2016; 55:4333-43. [PMID: 27400268 DOI: 10.1021/acs.biochem.6b00691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was applied to investigate the folding of an outer membrane protein, TtoA, assisted by TtOmp85, both from the thermophilic eubacterium Thermus thermophilus. To directly monitor the formation of β-sheet structure in TtoA and to analyze the function of TtOmp85, we immobilized unfolded TtoA on an ATR crystal. Interaction with TtOmp85 initiated TtoA folding as shown by time-dependent spectra recorded during the folding process. Our ATR-FTIR experiments prove that TtOmp85 possesses specific functionality to assist β-sheet formation of TtoA. We demonstrate the potential of this spectroscopic approach to study the interaction of outer membrane proteins in vitro and in a time-resolved manner.
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Affiliation(s)
- Katharina Henke
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Wolfram Welte
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Karin Hauser
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
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9
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Heinz E, Selkrig J, Belousoff MJ, Lithgow T. Evolution of the Translocation and Assembly Module (TAM). Genome Biol Evol 2015; 7:1628-43. [PMID: 25994932 PMCID: PMC4494059 DOI: 10.1093/gbe/evv097] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2015] [Indexed: 02/06/2023] Open
Abstract
Bacterial outer membrane proteins require the beta-barrel assembly machinery (BAM) for their correct folding and function. The central component of this machinery is BamA, an Omp85 protein that is essential and found in all Gram-negative bacteria. An additional feature of the BAM is the translocation and assembly module (TAM), comprised TamA (an Omp85 family protein) and TamB. We report that TamA and a closely related protein TamL are confined almost exclusively to Proteobacteria and Bacteroidetes/Chlorobi respectively, whereas TamB is widely distributed across the majority of Gram-negative bacterial lineages. A comprehensive phylogenetic and secondary structure analysis of the TamB protein family revealed that TamB was present very early in the evolution of bacteria. Several sequence characteristics were discovered to define the TamB protein family: A signal-anchor linkage to the inner membrane, beta-helical structure, conserved domain architecture and a C-terminal region that mimics outer membrane protein beta-strands. Taken together, the structural and phylogenetic analyses suggest that the TAM likely evolved from an original combination of BamA and TamB, with a later gene duplication event of BamA, giving rise to an additional Omp85 sequence that evolved to be TamA in Proteobacteria and TamL in Bacteroidetes/Chlorobi.
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Affiliation(s)
- Eva Heinz
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Joel Selkrig
- Department of Biochemistry & Molecular Biology, Monash University, Melbourne, Victoria, Australia Present address: European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Matthew J Belousoff
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Trevor Lithgow
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
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10
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Estrada Mallarino L, Fan E, Odermatt M, Müller M, Lin M, Liang J, Heinzelmann M, Fritsche F, Apell HJ, Welte W. TtOmp85, a β-barrel assembly protein, functions by barrel augmentation. Biochemistry 2015; 54:844-52. [PMID: 25537637 PMCID: PMC4310625 DOI: 10.1021/bi5011305] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Outer
membrane proteins are vital for Gram-negative bacteria and
organisms that inherited organelles from them. Proteins from the Omp85/BamA
family conduct the insertion of membrane proteins into the outer membrane.
We show that an eight-stranded outer membrane β-barrel protein,
TtoA, is inserted and folded into liposomes by an Omp85 homologue.
Furthermore, we recorded the channel conductance of this Omp85 protein
in black lipid membranes, alone and in the presence of peptides comprising
the sequence of the
two N-terminal and the two C-terminal β-strands of TtoA. Only
with the latter could a long-living compound channel that exhibits
conductance levels higher than those of the Omp85 protein alone be
observed. These data
support a model in which unfolded outer membrane protein after docking
with its C-terminus penetrates into the transmembrane β-barrel
of the Omp85 protein and augments its β-sheet at the first strand.
Augmentation with successive β-strands leads to a compound,
dilated barrel of both proteins.
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Affiliation(s)
- Luisa Estrada Mallarino
- Department of Biology, University of Konstanz , Universitätsstraße 10, 78457 Konstanz, Germany
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11
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Patel GJ, Kleinschmidt JH. The lipid bilayer-inserted membrane protein BamA of Escherichia coli facilitates insertion and folding of outer membrane protein A from its complex with Skp. Biochemistry 2013; 52:3974-86. [PMID: 23641708 DOI: 10.1021/bi400103t] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Folding of β-barrel membrane proteins, either from a urea-unfolded form or from chaperone-bound aqueous forms, has been characterized for pure lipid bilayers. The impact of preinserted integral proteins from biomembranes has not been examined in biophysical comparisons, but this knowledge is important for the characterization of protein assembly machinery in membranes to distinguish specific effects from unspecific effects. Here, folding was studied for a β-barrel membrane protein, outer membrane protein A (OmpA) from Escherichia coli, in the absence and presence of two other preinserted integral proteins, BamA of the β-barrel assembly machinery complex (BAM) from E. coli and FomA from Fusobacterium nucleatum. Three different preformed lipid membranes of phosphatidylcholine were prepared to compare the folding kinetics of OmpA, namely, proteoliposomes containing either BamA or FomA and pure liposomes. Urea-unfolded OmpA folded faster into phosphatidylcholine bilayers containing FomA than into pure lipid bilayers, but the kinetics of OmpA folding and insertion were fastest for bilayers containing BamA. Incorporation of BamA into lipid bilayers composed of phosphatidylcholine and phosphatidylethanolamine greatly weakened the inhibiting effect of phosphatidylethanolamine on the folding of OmpA. Folding of OmpA from its complex with the periplasmic chaperone Skp into bilayers composed of phosphatidylethanolamine and phosphatidylcholine was inhibited in the absence of BamA but facilitated when BamA was present, indicating an interaction of Skp-OmpA complexes with BamA.
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Affiliation(s)
- Geetika J Patel
- Fachbereich Biologie, Universität Konstanz, D-78457 Konstanz, Germany
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12
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Jacob-Dubuisson F, Guérin J, Baelen S, Clantin B. Two-partner secretion: as simple as it sounds? Res Microbiol 2013; 164:583-95. [PMID: 23542425 DOI: 10.1016/j.resmic.2013.03.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
Abstract
The two-partner secretion (TPS) pathway is a branch of type V secretion. TPS systems are dedicated to the secretion across the outer membrane of long proteins that form extended β-helices. They are composed of a 'TpsA' cargo protein and a 'TpsB' transporter, which belongs to the Omp85 superfamily. This basic design can be supplemented by additional components in some TPS systems. X-ray structures are available for the conserved TPS domain of several TpsA proteins and for one TpsB transporter. However, the molecular mechanisms of two-partner secretion remain to be deciphered, and in particular, the specific role(s) of the TPS domain and the conformational dynamics of the TpsB transporter. Deciphering the TPS pathway may reveal functional features of other transporters of the Omp85 superfamily.
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13
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Webb CT, Heinz E, Lithgow T. Evolution of the β-barrel assembly machinery. Trends Microbiol 2012; 20:612-20. [DOI: 10.1016/j.tim.2012.08.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/10/2012] [Accepted: 08/14/2012] [Indexed: 11/29/2022]
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14
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Misra R. Assembly of the β-Barrel Outer Membrane Proteins in Gram-Negative Bacteria, Mitochondria, and Chloroplasts. ISRN MOLECULAR BIOLOGY 2012; 2012:708203. [PMID: 27335668 PMCID: PMC4890855 DOI: 10.5402/2012/708203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 10/22/2012] [Indexed: 01/12/2023]
Abstract
In the last decade, there has been an explosion of publications on the assembly of β-barrel outer membrane proteins (OMPs), which carry out diverse cellular functions, including solute transport, protein secretion, and assembly of protein and lipid components of the outer membrane. Of the three outer membrane model systems—Gram-negative bacteria, mitochondria and chloroplasts—research on bacterial and mitochondrial systems has so far led the way in dissecting the β-barrel OMP assembly pathways. Many exciting discoveries have been made, including the identification of β-barrel OMP assembly machineries in bacteria and mitochondria, and potentially the core assembly component in chloroplasts. The atomic structures of all five components of the bacterial β-barrel assembly machinery (BAM) complex, except the β-barrel domain of the core BamA protein, have been solved. Structures reveal that these proteins contain domains/motifs known to facilitate protein-protein interactions, which are at the heart of the assembly pathways. While structural information has been valuable, most of our current understanding of the β-barrel OMP assembly pathways has come from genetic, molecular biology, and biochemical analyses. This paper provides a comparative account of the β-barrel OMP assembly pathways in Gram-negative bacteria, mitochondria, and chloroplasts.
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Affiliation(s)
- Rajeev Misra
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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15
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Acosta F, Ferreras E, Berenguer J. The β-barrel assembly machinery (BAM) is required for the assembly of a primitive S-layer protein in the ancient outer membrane of Thermus thermophilus. Extremophiles 2012; 16:853-61. [DOI: 10.1007/s00792-012-0480-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 08/27/2012] [Indexed: 12/22/2022]
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16
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Acosta F, de Pedro MA, Berenguer J. Homogeneous incorporation of secondary cell wall polysaccharides to the cell wall of Thermus thermophilus HB27. Extremophiles 2012; 16:485-95. [PMID: 22527042 DOI: 10.1007/s00792-012-0448-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/02/2012] [Indexed: 11/27/2022]
Abstract
Regular surface protein layers (S-layers) from most Gram-positive bacteria and from the ancestral bacterium Thermus thermophilus attach to pyruvylated polysaccharides (SCWP) covalently bound to the peptidoglycan through their SLH domain. However, it is not known whether the synthesis of SCWP and S-layer is coordinated enough as to follow a similar pattern of incorporation to the cell wall during growth. In this work we analyse the localization of newly synthesized SCWP on the cell wall of T. thermophilus by immunoelectron microscopy. For this, we obtained mutants with a reduced amount of pyruvylated SCWP through mutation of the csaB gene encoding the SCWP-pyruvylating activity, and its upstream gene csaA, a putative sugar transporter. We hypothesized that CsaA would be required for the synthesis of the SCWP. However, we found that csaA mutants showed only a minor decrease in the amount of SCWP immunodetected on the cell walls in comparison with csaB mutants, revealing its irrelevance in the process. Complementation experiments of csaB mutants with CsaB expressed from inducible promoters revealed that newly synthesized SCWP was homogeneously distributed along the cell wall. Fusions with thermostable fluorescent protein revealed that CsaB was distributed also in homogeneous pattern associated with the membrane. These data support that synthesis of SCWP takes place in disperse and homogeneous form all over the cell surface, in contrast to the zonal incorporation at the cell centre recently demonstrated for SlpA.
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Affiliation(s)
- Federico Acosta
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Campus de la UAM, 28049, Madrid, Spain
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17
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Burkhardt J, Vonck J, Langer JD, Salzer R, Averhoff B. Unusual N-terminal ααβαββα fold of PilQ from Thermus thermophilus mediates ring formation and is essential for piliation. J Biol Chem 2012; 287:8484-94. [PMID: 22253437 DOI: 10.1074/jbc.m111.334912] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA translocators of natural transformation systems are complex systems critical for the uptake of free DNA and provide a powerful mechanism for adaptation to changing environmental conditions. In natural transformation machineries, outer membrane secretins are suggested to form a multimeric pore for the uptake of external DNA. Recently, we reported on a novel structure of the DNA translocator secretin complex, PilQ, in Thermus thermophilus HB27 comprising a stable cone and cup structure and six ring structures with a large central channel. Here, we report on structural and functional analyses of a set of N-terminal PilQ deletion derivatives in T. thermophilus HB27. We identified 136 N-terminal residues exhibiting an unusual ααβαββα fold as a ring-building domain. Deletion of this domain had a dramatic effect on twitching motility, adhesion, and piliation but did not abolish natural transformation. These findings provide clear evidence that the pilus structures of T. thermophilus are not essential for natural transformation. The truncated complex was not affected in inner and outer membrane association, indicating that the 136 N-terminal residues are not essential for membrane targeting. Analyses of complex formation of the truncated PilQ monomers revealed that the region downstream of residue 136 is required for multimerization, and the region downstream of residue 207 is essential for monomer stability. Possible implications of our findings for the mechanism of DNA uptake are discussed.
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Affiliation(s)
- Janin Burkhardt
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
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18
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Delattre A, Saint N, Clantin B, Willery E, Lippens G, Locht C, Villeret V, Jacob‐Dubuisson F. Substrate recognition by the POTRA domains of TpsB transporter FhaC. Mol Microbiol 2011; 81:99-112. [DOI: 10.1111/j.1365-2958.2011.07680.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Anne‐Sophie Delattre
- Inserm U1019, Center for Infection and Immunity of Lille, F‐59019 Lille, France
- Institut Pasteur de Lille, F‐59019 Lille, France
- Univ Lille Nord de France, F‐59000 Lille, France
- CNRS UMR8204, F‐59021 Lille, France
| | - Nathalie Saint
- INSERM U1046, Université de Montpellier 1 et 2, F‐34090 Montpellier cedex, France
| | - Bernard Clantin
- CNRS USR3078, Institut de Recherche Interdisciplinaire – Université de Lille 1 – Université de Lille 2, F‐59658 Villeneuve d'Ascq, France
| | - Eve Willery
- Inserm U1019, Center for Infection and Immunity of Lille, F‐59019 Lille, France
- Institut Pasteur de Lille, F‐59019 Lille, France
- Univ Lille Nord de France, F‐59000 Lille, France
- CNRS UMR8204, F‐59021 Lille, France
| | - Guy Lippens
- CNRS UMR 8576 – Université de Lille I, F‐59655 Villeneuve d'Ascq – France
| | - Camille Locht
- Inserm U1019, Center for Infection and Immunity of Lille, F‐59019 Lille, France
- Institut Pasteur de Lille, F‐59019 Lille, France
- Univ Lille Nord de France, F‐59000 Lille, France
- CNRS UMR8204, F‐59021 Lille, France
| | - Vincent Villeret
- CNRS USR3078, Institut de Recherche Interdisciplinaire – Université de Lille 1 – Université de Lille 2, F‐59658 Villeneuve d'Ascq, France
| | - Françoise Jacob‐Dubuisson
- Inserm U1019, Center for Infection and Immunity of Lille, F‐59019 Lille, France
- Institut Pasteur de Lille, F‐59019 Lille, France
- Univ Lille Nord de France, F‐59000 Lille, France
- CNRS UMR8204, F‐59021 Lille, France
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19
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Desrosiers DC, Anand A, Luthra A, Dunham-Ems SM, LeDoyt M, Cummings MAD, Eshghi A, Cameron CE, Cruz AR, Salazar JC, Caimano MJ, Radolf JD. TP0326, a Treponema pallidum β-barrel assembly machinery A (BamA) orthologue and rare outer membrane protein. Mol Microbiol 2011; 80:1496-515. [PMID: 21488980 PMCID: PMC3115443 DOI: 10.1111/j.1365-2958.2011.07662.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Definitive identification of Treponema pallidum rare outer membrane proteins (OMPs) has long eluded researchers. TP0326, the sole protein in T. pallidum with sequence homology to a Gram-negative OMP, belongs to the BamA family of proteins essential for OM biogenesis. Structural modelling predicted that five polypeptide transport-associated (POTRA) domains comprise the N-terminus of TP0326, while the C-terminus forms an 18-stranded amphipathic β-barrel. Circular dichroism, heat modifiability by SDS-PAGE, Triton X-114 phase partitioning and liposome incorporation supported these topological predictions and confirmed that the β-barrel is responsible for the native protein's amphiphilicity. Expression analyses revealed that native TP0326 is expressed at low abundance, while a protease-surface accessibility assay confirmed surface exposure. Size-exclusion chromatography and blue native polyacrylamide gel electrophoresis revealed a modular Bam complex in T. pallidum larger than that of Escherichia coli. Non-orthologous ancillary factors and self-association of TP0326 via its β-barrel may both contribute to the Bam complex. T. pallidum-infected rabbits mount a vigorous antibody response to both POTRA and β-barrel portions of TP0326, whereas humans with secondary syphilis respond predominantly to POTRA. The syphilis spirochaete appears to have devised a stratagem for harnessing the Bam pathway while satisfying its need to limit surface antigenicity.
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Affiliation(s)
- Daniel C. Desrosiers
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Arvind Anand
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Amit Luthra
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Star M Dunham-Ems
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Morgan LeDoyt
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Michael A. D. Cummings
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Azad Eshghi
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Caroline E. Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Adriana R. Cruz
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Juan C. Salazar
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
- Department of Pediatrics, Connecticut Children's Medical Center, Division of Pediatric Infectious Diseases, Hartford, CT 06106
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
| | - Justin D. Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030
- Department of Pediatrics, Connecticut Children's Medical Center, Division of Pediatric Infectious Diseases, Hartford, CT 06106
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20
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Delattre AS, Clantin B, Saint N, Locht C, Villeret V, Jacob-Dubuisson F. Functional importance of a conserved sequence motif in FhaC, a prototypic member of the TpsB/Omp85 superfamily. FEBS J 2010; 277:4755-65. [PMID: 20955520 DOI: 10.1111/j.1742-4658.2010.07881.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In Gram-negative bacteria, the two-partner secretion pathway mediates the secretion of TpsA proteins with various functions. TpsB transporters specifically recognize their TpsA partners in the periplasm and mediate their transport through a hydrophilic channel. The filamentous haemagglutinin adhesin (FHA)/FhaC pair represents a model two-partner secretion system, with the structure of the TpsB transporter FhaC providing the bases to decipher the mechanism of action of these proteins. FhaC is composed of a β-barrel preceded by two periplasmic polypeptide-transport-associated (POTRA) domains in tandem. The barrel is occluded by an N-terminal helix and an extracellular loop, L6, folded back into the FhaC channel. In this article, we describe a functionally important motif of FhaC. The VRGY tetrad is highly conserved in the TpsB family and, in FhaC, it is located at the tip of L6 reaching the periplasm. Replacement by Ala of the invariant Arg dramatically affects the secretion efficiency, although the structure of FhaC and its channel properties remain unaffected. This substitution affects the secretion mechanism at a step beyond the initial TpsA-TpsB interaction. Replacement of the conserved Tyr affects the channel properties, but not the secretion activity, suggesting that this residue stabilizes the loop in the resting conformation of FhaC. Thus, the conserved motif at the tip of L6 represents an important piece of two-partner secretion machinery. This motif is conserved in a predicted loop between two β-barrel strands in more distant relatives of FhaC involved in protein transport across or assembly into the outer membranes of bacteria and organelles, suggesting a conserved function in the molecular mechanism of transport.
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21
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Sutcliffe IC. A phylum level perspective on bacterial cell envelope architecture. Trends Microbiol 2010; 18:464-70. [DOI: 10.1016/j.tim.2010.06.005] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/04/2010] [Accepted: 06/18/2010] [Indexed: 01/03/2023]
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22
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Arnold T, Zeth K, Linke D. Omp85 from the thermophilic cyanobacterium Thermosynechococcus elongatus differs from proteobacterial Omp85 in structure and domain composition. J Biol Chem 2010; 285:18003-15. [PMID: 20351097 PMCID: PMC2878562 DOI: 10.1074/jbc.m110.112516] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 03/26/2010] [Indexed: 12/03/2022] Open
Abstract
Omp85 proteins are essential proteins located in the bacterial outer membrane. They are involved in outer membrane biogenesis and assist outer membrane protein insertion and folding by an unknown mechanism. Homologous proteins exist in eukaryotes, where they mediate outer membrane assembly in organelles of endosymbiotic origin, the mitochondria and chloroplasts. We set out to explore the homologous relationship between cyanobacteria and chloroplasts, studying the Omp85 protein from the thermophilic cyanobacterium Thermosynechococcus elongatus. Using state-of-the art sequence analysis and clustering methods, we show how this protein is more closely related to its chloroplast homologue Toc75 than to proteobacterial Omp85, a finding supported by single channel conductance measurements. We have solved the structure of the periplasmic part of the protein to 1.97 A resolution, and we demonstrate that in contrast to Omp85 from Escherichia coli the protein has only three, not five, polypeptide transport-associated (POTRA) domains, which recognize substrates and generally interact with other proteins in bigger complexes. We model how these POTRA domains are attached to the outer membrane, based on the relationship of Omp85 to two-partner secretion system proteins, which we show and analyze. Finally, we discuss how Omp85 proteins with different numbers of POTRA domains evolved, and evolve to this day, to accomplish an increasing number of interactions with substrates and helper proteins.
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Affiliation(s)
- Thomas Arnold
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Kornelius Zeth
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Dirk Linke
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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23
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Walther DM, Rapaport D, Tommassen J. Biogenesis of beta-barrel membrane proteins in bacteria and eukaryotes: evolutionary conservation and divergence. Cell Mol Life Sci 2009; 66:2789-804. [PMID: 19399587 PMCID: PMC2724633 DOI: 10.1007/s00018-009-0029-z] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 03/26/2009] [Accepted: 04/01/2009] [Indexed: 01/01/2023]
Abstract
Membrane-embedded beta-barrel proteins span the membrane via multiple amphipathic beta-strands arranged in a cylindrical shape. These proteins are found in the outer membranes of Gram-negative bacteria, mitochondria and chloroplasts. This situation is thought to reflect the evolutionary origin of mitochondria and chloroplasts from Gram-negative bacterial endosymbionts. beta-barrel proteins fulfil a variety of functions; among them are pore-forming proteins that allow the flux of metabolites across the membrane by passive diffusion, active transporters of siderophores, enzymes, structural proteins, and proteins that mediate protein translocation across or insertion into membranes. The biogenesis process of these proteins combines evolutionary conservation of the central elements with some noticeable differences in signals and machineries. This review summarizes our current knowledge of the functions and biogenesis of this special family of proteins.
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Affiliation(s)
- Dirk M. Walther
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
| | - Doron Rapaport
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Jan Tommassen
- Department of Molecular Microbiology, Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands
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24
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Jacob-Dubuisson F, Villeret V, Clantin B, Delattre AS, Saint N. First structural insights into the TpsB/Omp85 superfamily. Biol Chem 2009; 390:675-84. [DOI: 10.1515/bc.2009.099] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Abstract
Proteins of the TpsB/Omp85 superfamily are involved in protein transport across, or assembly into, the outer membrane of Gram-negative bacteria, and their distant eukaryotic relatives exert similar functions in chloroplasts and mitochondria. The X-ray structure of one TpsB transporter, FhaC, provides the bases to decipher the mechanisms of action of these proteins. With two POTRA domains in the periplasm, a transmembrane β barrel and a large loop harboring a functionally important motif, FhaC epitomizes the conserved features of the super-family.
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25
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Brosig A, Nesper J, Boos W, Welte W, Diederichs K. Crystal Structure of a Major Outer Membrane Protein from Thermus thermophilus HB27. J Mol Biol 2009; 385:1445-55. [DOI: 10.1016/j.jmb.2008.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/25/2008] [Accepted: 12/02/2008] [Indexed: 11/30/2022]
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26
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Thermus thermophilus as biological model. Extremophiles 2009; 13:213-31. [DOI: 10.1007/s00792-009-0226-6] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/31/2008] [Indexed: 10/21/2022]
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27
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Brosig A, Nesper J, Welte W, Diederichs K. Expression, crystallization and preliminary X-ray analysis of an outer membrane protein from Thermus thermophilus HB27. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:533-6. [PMID: 18540069 DOI: 10.1107/s1744309108013602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 05/07/2008] [Indexed: 11/10/2022]
Abstract
The cell envelope of the thermophilic bacterium Thermus thermophilus is multilayered and includes an outer membrane with integral outer membrane proteins that are not well characterized. The hypothetical protein TTC0834 from T. thermophilus HB27 was identified as a 22 kDa outer membrane protein containing eight predicted beta-strands. TTC0834 was expressed with an N-terminal His tag in T. thermophilus HB8 and detected in the S-layer/outer membrane envelope fraction. His-TTC0834 was purified and crystallized under various conditions. Native data sets were collected to 3.2 A resolution and the best diffracting crystals belonged to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 166.67, c = 97.53 A.
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Affiliation(s)
- Alexander Brosig
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
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