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Kolich LR, Chang YT, Coudray N, Giacometti SI, MacRae MR, Isom GL, Teran EM, Bhabha G, Ekiert DC. Structure of MlaFB uncovers novel mechanisms of ABC transporter regulation. eLife 2020; 9:e60030. [PMID: 32602838 PMCID: PMC7367683 DOI: 10.7554/elife.60030] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 06/24/2020] [Indexed: 12/12/2022] Open
Abstract
ABC transporters facilitate the movement of diverse molecules across cellular membranes, but how their activity is regulated post-translationally is not well understood. Here we report the crystal structure of MlaFB from E. coli, the cytoplasmic portion of the larger MlaFEDB ABC transporter complex, which drives phospholipid trafficking across the bacterial envelope to maintain outer membrane integrity. MlaB, a STAS domain protein, binds the ABC nucleotide binding domain, MlaF, and is required for its stability. Our structure also implicates a unique C-terminal tail of MlaF in self-dimerization. Both the C-terminal tail of MlaF and the interaction with MlaB are required for the proper assembly of the MlaFEDB complex and its function in cells. This work leads to a new model for how an important bacterial lipid transporter may be regulated by small proteins, and raises the possibility that similar regulatory mechanisms may exist more broadly across the ABC transporter family.
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Affiliation(s)
- Ljuvica R Kolich
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Ya-Ting Chang
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Nicolas Coudray
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
- Applied Bioinformatics Laboratory, New York University School of MedicineNew YorkUnited States
| | - Sabrina I Giacometti
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Mark R MacRae
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Georgia L Isom
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Evelyn M Teran
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Gira Bhabha
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Damian C Ekiert
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
- Department of Microbiology, New York University School of MedicineNew YorkUnited States
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Abstract
The stressosome is a multi-protein signal integration and transduction hub found in a wide range of bacterial species. The role that the stressosome plays in regulating the transcription of genes involved in the general stress response has been studied most extensively in the Gram-positive model organism Bacillus subtilis. The stressosome receives and relays the signal(s) that initiate a complex phosphorylation-dependent partner switching cascade, resulting in the activation of the alternative sigma factor σB. This sigma factor controls transcription of more than 150 genes involved in the general stress response. X-ray crystal structures of individual components of the stressosome and single-particle cryo-EM reconstructions of stressosome complexes, coupled with biochemical and single cell analyses, have permitted a detailed understanding of the dynamic signalling behaviour that arises from this multi-protein complex. Furthermore, bioinformatics analyses indicate that genetic modules encoding key stressosome proteins are found in a wide range of bacterial species, indicating an evolutionary advantage afforded by stressosome complexes. Interestingly, the genetic modules are associated with a variety of signalling modules encoding secondary messenger regulation systems, as well as classical two-component signal transduction systems, suggesting a diversification in function. In this chapter we review the current research into stressosome systems and discuss the functional implications of the unique structure of these signalling complexes.
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Lomize AL, Pogozheva ID. Solvation models and computational prediction of orientations of peptides and proteins in membranes. Methods Mol Biol 2013; 1063:125-42. [PMID: 23975775 DOI: 10.1007/978-1-62703-583-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane-associated peptides and proteins function in the highly heterogeneous environment of the lipid bilayer whose physico-chemical properties change non-monotonically along the bilayer normal. To simulate insertion of peptides and proteins into membranes and correctly reproduce the energetics of this process, an adequate solvation model and physically realistic representation of the lipid bilayer should be employed. We present a brief overview of the existing solvation models and their application for prediction of binding affinities and orientations of proteins in membranes. Particular emphasis is placed on the recently proposed PPM method, the corresponding web server, and the OPM database that were designed for positioning in membranes of integral and peripheral proteins with known three-dimensional structures.
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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Zhang WX, Thakur V, Lomize A, Pogozheva I, Panagabko C, Cecchini M, Baptist M, Morley S, Manor D, Atkinson J. The contribution of surface residues to membrane binding and ligand transfer by the α-tocopherol transfer protein (α-TTP). J Mol Biol 2010; 405:972-88. [PMID: 21110980 DOI: 10.1016/j.jmb.2010.11.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 11/13/2010] [Indexed: 12/20/2022]
Abstract
Previous work has shown that the α-tocopherol transfer protein (α-TTP) can bind to vesicular or immobilized phospholipid membranes. Revealing the molecular mechanisms by which α-TTP associates with membranes is thought to be critical to understanding its function and role in the secretion of tocopherol from hepatocytes into the circulation. Calculations presented in the Orientations of Proteins in Membranes database have provided a testable model for the spatial arrangement of α-TTP and other CRAL-TRIO family proteins with respect to the lipid bilayer. These calculations predicted that a hydrophobic surface mediates the interaction of α-TTP with lipid membranes. To test the validity of these predictions, we used site-directed mutagenesis and examined the substituted mutants with regard to intermembrane ligand transfer, association with lipid layers and biological activity in cultured hepatocytes. Substitution of residues in helices A8 (F165A and F169A) and A10 (I202A, V206A and M209A) decreased the rate of intermembrane ligand transfer as well as protein adsorption to phospholipid bilayers. The largest impairment was observed upon mutation of residues that are predicted to be fully immersed in the lipid bilayer in both apo (open) and holo (closed) conformations such as Phe165 and Phe169. Mutation F169A, and especially F169D, significantly impaired α-TTP-assisted secretion of α-tocopherol outside cultured hepatocytes. Mutation of selected basic residues (R192H, K211A, and K217A) had little effect on transfer rates, indicating no significant involvement of nonspecific electrostatic interactions with membranes.
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Affiliation(s)
- Wen Xiao Zhang
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada L2S3A1
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Koonin EV. New variants of known folds: do they bring new biology? Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1226-9. [PMID: 20944215 PMCID: PMC2954209 DOI: 10.1107/s1744309110013242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/09/2010] [Indexed: 05/30/2023]
Abstract
New distinct versions of known protein folds provide a powerful means of protein-function prediction that complements sequence and genomic context analysis. These structures do not supplant direct biochemical experiments, but are indispensable for the complete characterization of proteins.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, Maryland 20894, USA.
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Krishna SS, Weekes D, Bakolitsa C, Elsliger MA, Wilson IA, Godzik A, Wooley J. TOPSAN: use of a collaborative environment for annotating, analyzing and disseminating data on JCSG and PSI structures. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1143-7. [PMID: 20944203 PMCID: PMC2954197 DOI: 10.1107/s1744309110035736] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 09/06/2010] [Indexed: 11/17/2022]
Abstract
The NIH Protein Structure Initiative centers, such as the Joint Center for Structural Genomics (JCSG), have developed highly efficient technological platforms that are capable of experimentally determining the three-dimensional structures of hundreds of proteins per year. However, the overwhelming majority of the almost 5000 protein structures determined by these centers have yet to be described in the peer-reviewed literature. In a high-throughput structural genomics environment, the process of structure determination occurs independently of any associated experimental characterization of function, which creates a challenge for the annotation and analysis of structures and the publication of these results. This challenge has been addressed by developing TOPSAN (`The Open Protein Structure Annotation Network'), which enables the generation of knowledge via collaborations among globally distributed contributors supported by automated amalgamation of available information. TOPSAN currently provides annotations for all protein structures determined by the JCSG in addition to preliminary annotations on a large number of structures from the other PSI production centers. TOPSAN-enabled collaborations have resulted in insightful structure-function analysis for many proteins and have led to numerous peer-reviewed publications, as exemplified by the articles included in this issue of Acta Crystallographica Section F.
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Affiliation(s)
- S. Sri Krishna
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, California, USA
| | - Dana Weekes
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, California, USA
| | - Constantina Bakolitsa
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, California, USA
| | - Marc-André Elsliger
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Ian A. Wilson
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Adam Godzik
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, California, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, California, USA
| | - John Wooley
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, California, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, California, USA
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Andreeva A, Murzin AG. Structural classification of proteins and structural genomics: new insights into protein folding and evolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1190-7. [PMID: 20944210 PMCID: PMC2954204 DOI: 10.1107/s1744309110007177] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 02/24/2010] [Indexed: 11/10/2022]
Abstract
During the past decade, the Protein Structure Initiative (PSI) centres have become major contributors of new families, superfamilies and folds to the Structural Classification of Proteins (SCOP) database. The PSI results have increased the diversity of protein structural space and accelerated our understanding of it. This review article surveys a selection of protein structures determined by the Joint Center for Structural Genomics (JCSG). It presents previously undescribed β-sheet architectures such as the double barrel and spiral β-roll and discusses new examples of unusual topologies and peculiar structural features observed in proteins characterized by the JCSG and other Structural Genomics centres.
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Affiliation(s)
- Antonina Andreeva
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, England
| | - Alexey G. Murzin
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, England
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