1
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Rahman MM, Zamakhaeva S, Rush JS, Chaton CT, Kenner CW, Hla YM, Tsui HCT, Uversky VN, Winkler ME, Korotkov KV, Korotkova N. O-glycosylation of intrinsically disordered regions regulates homeostasis of membrane proteins in streptococci. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.05.592596. [PMID: 38746434 PMCID: PMC11092751 DOI: 10.1101/2024.05.05.592596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Proteins harboring intrinsically disordered regions (IDRs) lacking stable secondary or tertiary structures are abundant across the three domains of life. These regions have not been systematically studied in prokaryotes. Our genome-wide analysis identifies extracytoplasmic serine/threonine-rich IDRs in several biologically important membrane proteins in streptococci. We demonstrate that these IDRs are O-glycosylated with glucose by glycosyltransferases GtrB and PgtC2 in Streptococcus pyogenes and Streptococcus pneumoniae, and with N-acetylgalactosamine by a Pgf-dependent mechanism in Streptococcus mutans. Absence of glycosylation leads to a defect in biofilm formation under ethanol-stressed conditions in S. mutans. We link this phenotype to the C-terminal IDR of a post-translocation secretion chaperone PrsA. O-glycosylation of the IDR protects this region from proteolytic degradation. The IDR length attenuates the efficiency of glycosylation and, consequently, the expression level of PrsA. Taken together, our data reveal that O-glycosylation of IDRs functions as a dynamic switch of protein homeostasis in streptococci.
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Affiliation(s)
- Mohammad M. Rahman
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Svetlana Zamakhaeva
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Jeffrey S. Rush
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Catherine T. Chaton
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Cameron W. Kenner
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Yin Mon Hla
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | | | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
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2
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TagElDein MA, Mohamed NG, Shahein YE, Ziko L, Hussein NA. Altering Escherichia coli envelope integrity by mimicking the lipoprotein RcsF. Arch Microbiol 2023; 206:12. [PMID: 38070002 PMCID: PMC10710380 DOI: 10.1007/s00203-023-03733-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 10/21/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023]
Abstract
Escherichia coli cell envelope is crucial for stress sensing and signal transduction, mediated by numerous protein-protein interactions to enable adaptation and survival. Interfering with these interactions might affect envelope integrity leading to bacterial death. The outer membrane lipoprotein (RcsF) is the stress sensor of the regulator of capsule synthesis (Rcs) phosphorelay that senses envelope threats. RcsF interacts with two essential proteins, IgaA (repressing the Rcs system) and BamA (inserting β-barrel proteins in the outer membrane). Disturbing RcsF interactions may alter Rcs signaling and/or membrane integrity thus affecting bacterial survival. Here, we derived the sequence of a peptide mimicking RcsF (RcsFmim), based on the in silico docking of RcsF with IgaA. Expression of rcsFmim caused 3-to-4-fold activation of the Rcs system and perturbation of the outer membrane. Both effects result in decreased E. coli growth rate. We anticipate that RcsFmim present a candidate for future antibacterial peptide development.
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Affiliation(s)
- Moustafa A TagElDein
- Microbiology and Immunology Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Noha G Mohamed
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Sphinx University, Assiut, Egypt
| | - Yasser E Shahein
- Molecular Biology Department, Biotechnology Research Institute, National Research Centre, Cairo, Egypt
| | - Laila Ziko
- Department of Biochemistry, School of Life and Medical Sciences, University of Hertfordshire Hosted By the Global Academic Foundation, R5 New Garden City, New Administrative Capital, Cairo, Egypt
| | - Nahla A Hussein
- Molecular Biology Department, Biotechnology Research Institute, National Research Centre, Cairo, Egypt.
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3
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Levy JG, Oh J, Mendoza Herrera A, Parida A, Lao L, Starkey J, Yuan P, Kan CC, Tamborindeguy C. A ' Candidatus Liberibacter solanacearum' Haplotype B-Specific Family of Candidate Bacterial Effectors. PHYTOPATHOLOGY 2023; 113:1708-1715. [PMID: 37665323 DOI: 10.1094/phyto-11-22-0438-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
'Candidatus Liberibacter solanacearum' (Lso) is a phloem-limited pathogen associated with devastating diseases in members of the Solanaceae and Apiaceae and vectored by several psyllid species. Different Lso haplotypes have been identified, and LsoA and LsoB are responsible for diseases in Solanaceae crops. Our efforts are aimed at identifying pathogenicity factors used by this bacterium to thrive in different hosts. Bacterial secreted proteins can play a role in host colonization or the manipulation of the host immune responses; these proteins are called effectors. In this study, we identified six LsoB-specific proteins with a conserved secretion motif as well as a conserved N-terminal domain in the mature protein. These proteins had different expression and secretion patterns but a similar subcellular localization in Nicotiana benthamiana leaves, suggesting that they play different roles regardless of their conserved secretion motif. One of these proteins, CKC_04425, was expressed at high levels in the insect vector and the host plant, indicating that it could play a role in both the plant and insect hosts, whereas the others were mainly expressed in the plant. One protein, CKC_05701, was able to efficiently suppress programmed cell death and reactive oxygen species production, suggesting that it may have a virulence role in LsoB-specific pathogenesis.
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Affiliation(s)
- Julien G Levy
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843
| | - Junepyo Oh
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | | | - Adwaita Parida
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | - Loi Lao
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | - Jesse Starkey
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | - Peiguo Yuan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843
| | - Chia-Cheng Kan
- Department of Entomology, Texas A&M University, College Station, TX 77843
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4
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McClain MS, Bryant KN, McDonald WH, Algood HMS, Cover TL. Identification of an Essential LolD-Like Protein in Helicobacter pylori. J Bacteriol 2023; 205:e0005223. [PMID: 36971548 PMCID: PMC10127691 DOI: 10.1128/jb.00052-23] [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: 02/03/2023] [Accepted: 02/24/2023] [Indexed: 03/29/2023] Open
Abstract
The localization of lipoprotein (Lol) system is used by Gram-negative bacteria to export lipoproteins to the outer membrane. Lol proteins and models of how Lol transfers lipoproteins from the inner to the outer membrane have been extensively characterized in the model organism Escherichia coli, but in numerous bacterial species, lipoprotein synthesis and export pathways deviate from the E. coli paradigm. For example, in the human gastric bacterium Helicobacter pylori, a homolog of the E. coli outer membrane component LolB is not found, E. coli LolC and LolE correspond to a single inner membrane component (LolF), and a homolog of the E. coli cytoplasmic ATPase LolD has not been identified. In the present study, we sought to identify a LolD-like protein in H. pylori. We used affinity-purification mass spectrometry to identify interaction partners of the H. pylori ATP-binding cassette (ABC) family permease LolF and identified the ABC family ATP-binding protein HP0179 as its interaction partner. We engineered H. pylori to conditionally express HP0179 and showed that HP0179 and its conserved ATP binding and ATP hydrolysis motifs are essential for H. pylori growth. We then performed affinity purification-mass spectrometry using HP0179 as the bait and identified LolF as its interaction partner. These results indicate that H. pylori HP0179 is a LolD-like protein and provide a more complete understanding of lipoprotein localization processes in H. pylori, a bacterium in which the Lol system deviates from the E. coli paradigm. IMPORTANCE Lipoproteins are critical in Gram-negative-bacteria for cell surface assembly of LPS, insertion of outer membrane proteins, and sensing envelope stress. Lipoproteins also contribute to bacterial pathogenesis. For many of these functions, lipoproteins must localize to the Gram-negative outer membrane. Transporting lipoproteins to the outer membrane involves the Lol sorting pathway. Detailed analyses of the Lol pathway have been performed in the model organism Escherichia coli, but many bacteria utilize altered components or are missing essential components of the E. coli Lol pathway. Identifying a LolD-like protein in Helicobacter pylori is important to better understand the Lol pathway in diverse bacterial classes. This becomes particularly relevant as lipoprotein localization is targeted for antimicrobial development.
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Affiliation(s)
- Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Kaeli N. Bryant
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - W. Hayes McDonald
- Proteomics Laboratory, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Holly M. Scott Algood
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Timothy L. Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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5
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Vercruysse M, Dylus D. Special issue of BBA reviews — Molecular Cell Research: The Gram-negative envelope and potential targets for novel antibiotics. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2023; 1870:119472. [PMID: 37011731 DOI: 10.1016/j.bbamcr.2023.119472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/08/2023] [Accepted: 02/27/2023] [Indexed: 04/03/2023]
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6
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Cho SH, Dekoninck K, Collet JF. Envelope-Stress Sensing Mechanism of Rcs and Cpx Signaling Pathways in Gram-Negative Bacteria. J Microbiol 2023; 61:317-329. [PMID: 36892778 DOI: 10.1007/s12275-023-00030-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 03/10/2023]
Abstract
The global public health burden of bacterial antimicrobial resistance (AMR) is intensified by Gram-negative bacteria, which have an additional membrane, the outer membrane (OM), outside of the peptidoglycan (PG) cell wall. Bacterial two-component systems (TCSs) aid in maintaining envelope integrity through a phosphorylation cascade by controlling gene expression through sensor kinases and response regulators. In Escherichia coli, the major TCSs defending cells from envelope stress and adaptation are Rcs and Cpx, which are aided by OM lipoproteins RcsF and NlpE as sensors, respectively. In this review, we focus on these two OM sensors. β-Barrel assembly machinery (BAM) inserts transmembrane OM proteins (OMPs) into the OM. BAM co-assembles RcsF, the Rcs sensor, with OMPs, forming the RcsF-OMP complex. Researchers have presented two models for stress sensing in the Rcs pathway. The first model suggests that LPS perturbation stress disassembles the RcsF-OMP complex, freeing RcsF to activate Rcs. The second model proposes that BAM cannot assemble RcsF into OMPs when the OM or PG is under specific stresses, and thus, the unassembled RcsF activates Rcs. These two models may not be mutually exclusive. Here, we evaluate these two models critically in order to elucidate the stress sensing mechanism. NlpE, the Cpx sensor, has an N-terminal (NTD) and a C-terminal domain (CTD). A defect in lipoprotein trafficking results in NlpE retention in the inner membrane, provoking the Cpx response. Signaling requires the NlpE NTD, but not the NlpE CTD; however, OM-anchored NlpE senses adherence to a hydrophobic surface, with the NlpE CTD playing a key role in this function.
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Affiliation(s)
- Seung-Hyun Cho
- WELBIO-Walloon Excellence in Life Sciences and Biotechnology, 1200, Brussels, Belgium. .,de Duve Institute, Université Catholique de Louvain, 1200, Brussels, Belgium.
| | - Kilian Dekoninck
- WELBIO-Walloon Excellence in Life Sciences and Biotechnology, 1200, Brussels, Belgium.,de Duve Institute, Université Catholique de Louvain, 1200, Brussels, Belgium.,University of California, Berkeley, CA, 94720, USA
| | - Jean-Francois Collet
- WELBIO-Walloon Excellence in Life Sciences and Biotechnology, 1200, Brussels, Belgium.,de Duve Institute, Université Catholique de Louvain, 1200, Brussels, Belgium
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7
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Lach SR, Kumar S, Kim S, Im W, Konovalova A. Conformational rearrangements in the sensory RcsF/OMP complex mediate signal transduction across the bacterial cell envelope. PLoS Genet 2023; 19:e1010601. [PMID: 36706155 PMCID: PMC9907809 DOI: 10.1371/journal.pgen.1010601] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 02/08/2023] [Accepted: 01/06/2023] [Indexed: 01/28/2023] Open
Abstract
Timely detection and repair of envelope damage are paramount for bacterial survival. The Regulator of Capsule Synthesis (Rcs) stress response can transduce the stress signals across the multilayered gram-negative cell envelope to regulate gene expression in the cytoplasm. Previous studies defined the overall pathway, which begins with the sensory lipoprotein RcsF interacting with several outer membrane proteins (OMPs). RcsF can also interact with the periplasmic domain of the negative regulator IgaA, derepressing the downstream RcsCDB phosphorelay. However, how the RcsF/IgaA interaction is regulated at the molecular level to activate the signaling in response to stress remains poorly understood. In this study, we used a site-saturated mutant library of rcsF to carry out several independent genetic screens to interrogate the mechanism of signal transduction from RcsF to IgaA. We analyzed several distinct classes of rcsF signaling mutants, and determined the region of RcsF that is critically important for signal transduction. This region is bifunctional as it is important for RcsF interaction with both IgaA and OMPs. The mutant analysis provides strong evidence for conformational changes in the RcsF/OMP complex mediating signal transduction to IgaA, and the first direct evidence that OMPs play an important regulatory role in Rcs signaling.
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Affiliation(s)
- Sarah R. Lach
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- The University of Texas MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas, United States of America
| | - Santosh Kumar
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Seonghoon Kim
- Departments of Biological Sciences, Chemistry, Bioengineering, and Computer Science and Engineering, Lehigh University, Bethlehem, Pennsylvania, United States of America
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Republic of Korea
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, Bioengineering, and Computer Science and Engineering, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Anna Konovalova
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- The University of Texas MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas, United States of America
- * E-mail:
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8
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Structural basis of lipoprotein recognition by the bacterial Lol trafficking chaperone LolA. Proc Natl Acad Sci U S A 2022; 119:e2208662119. [PMID: 36037338 PMCID: PMC9457489 DOI: 10.1073/pnas.2208662119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lipoproteins in gram-negative bacteria underpin the formation and maintenance of the outer membrane that constitutes a vital protective barrier against antibiotics and other noxious molecules. An essential transport system comprising the LolABCDE proteins is required to traffic lipoproteins to the outer membrane. Following maturation on the inner membrane and extraction by the LolCDE transporter, lipoproteins are passed to the chaperone LolA that carries them across the periplasm prior to insertion into the outer membrane by the LolB receptor. Here, we report the molecular details of lipoprotein interaction with the chaperone LolA, a key intermediate located at the heart of the Lol pathway. The structure provides valuable insights into this important system and could be exploited to develop new antimicrobials. In gram-negative bacteria, lipoproteins are vital structural components of the outer membrane (OM) and crucial elements of machineries central to the physiology of the cell envelope. A dedicated apparatus, the Lol system, is required for the correct localization of OM lipoproteins and is essential for viability. The periplasmic chaperone LolA is central to this trafficking pathway, accepting triacylated lipoproteins from the inner membrane transporter LolCDE, before carrying them across the periplasm to the OM receptor LolB. Here, we report a crystal structure of liganded LolA, generated in vivo, revealing the molecular details of lipoprotein association. The structure highlights how LolA, initially primed to receive lipoprotein by interaction with LolC, further opens to accommodate the three ligand acyl chains in a precise conformation within its cavity. LolA forms extensive interactions with the acyl chains but not with any residue of the cargo, explaining the chaperone’s ability to transport structurally diverse lipoproteins. Structural characterization of a ligandedLolA variant incapable of lipoprotein release reveals aberrant association, demonstrating the importance of the LolCDE-coordinated, sequential opening of LolA for inserting lipoprotein in a manner productive for subsequent trafficking. Comparison with existing structures of LolA in complex with LolC or LolCDE reveals substantial overlap of the lipoprotein and LolC binding sites within the LolA cavity, demonstrating that insertion of lipoprotein acyl chains physically disengages the chaperone protein from the transporter by perturbing interaction with LolC. Taken together, our data provide a key step toward a complete understanding of a fundamentally important trafficking pathway.
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9
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Grossman AS, Escobar CA, Mans EJ, Mucci NC, Mauer TJ, Jones KA, Moore CC, Abraham PE, Hettich RL, Schneider L, Campagna SR, Forest KT, Goodrich-Blair H. A Surface Exposed, Two-Domain Lipoprotein Cargo of a Type XI Secretion System Promotes Colonization of Host Intestinal Epithelia Expressing Glycans. Front Microbiol 2022; 13:800366. [PMID: 35572647 PMCID: PMC9100927 DOI: 10.3389/fmicb.2022.800366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/07/2022] [Indexed: 11/17/2022] Open
Abstract
The only known required component of the newly described Type XI secretion system (TXISS) is an outer membrane protein (OMP) of the DUF560 family. TXISSOMPs are broadly distributed across proteobacteria, but properties of the cargo proteins they secrete are largely unexplored. We report biophysical, histochemical, and phenotypic evidence that Xenorhabdus nematophila NilC is surface exposed. Biophysical data and structure predictions indicate that NilC is a two-domain protein with a C-terminal, 8-stranded β-barrel. This structure has been noted as a common feature of TXISS effectors and may be important for interactions with the TXISSOMP. The NilC N-terminal domain is more enigmatic, but our results indicate it is ordered and forms a β-sheet structure, and bioinformatics suggest structural similarities to carbohydrate-binding proteins. X. nematophila NilC and its presumptive TXISSOMP partner NilB are required for colonizing the anterior intestine of Steinernema carpocapsae nematodes: the receptacle of free-living, infective juveniles and the anterior intestinal cecum (AIC) in juveniles and adults. We show that, in adult nematodes, the AIC expresses a Wheat Germ Agglutinin (WGA)-reactive material, indicating the presence of N-acetylglucosamine or N-acetylneuraminic acid sugars on the AIC surface. A role for this material in colonization is supported by the fact that exogenous addition of WGA can inhibit AIC colonization by X. nematophila. Conversely, the addition of exogenous purified NilC increases the frequency with which X. nematophila is observed at the AIC, demonstrating that abundant extracellular NilC can enhance colonization. NilC may facilitate X. nematophila adherence to the nematode intestinal surface by binding to host glycans, it might support X. nematophila nutrition by cleaving sugars from the host surface, or it might help protect X. nematophila from nematode host immunity. Proteomic and metabolomic analyses of wild type X. nematophila compared to those lacking nilB and nilC revealed differences in cell wall and secreted polysaccharide metabolic pathways. Additionally, purified NilC is capable of binding peptidoglycan, suggesting that periplasmic NilC may interact with the bacterial cell wall. Overall, these findings support a model that NilB-regulated surface exposure of NilC mediates interactions between X. nematophila and host surface glycans during colonization. This is a previously unknown function for a TXISS.
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Affiliation(s)
- Alex S. Grossman
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Cristian A. Escobar
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
| | - Erin J. Mans
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Nicholas C. Mucci
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Terra J. Mauer
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
| | - Katarina A. Jones
- Department of Chemistry, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Cameron C. Moore
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Liesel Schneider
- Department of Animal Sciences, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Shawn R. Campagna
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biological and Small Molecule Mass Spectrometry Core, The University of Tennessee, Knoxville, Knoxville, TN, United States
- The University of Tennessee Oak Ridge Innovation Institute, Knoxville, TN, United States
| | - Katrina T. Forest
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
- Katrina T. Forest,
| | - Heidi Goodrich-Blair
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
- *Correspondence: Heidi Goodrich-Blair,
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10
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Smithers L, Olatunji S, Caffrey M. Bacterial Lipoprotein Posttranslational Modifications. New Insights and Opportunities for Antibiotic and Vaccine Development. Front Microbiol 2021; 12:788445. [PMID: 34950121 PMCID: PMC8689077 DOI: 10.3389/fmicb.2021.788445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/16/2021] [Indexed: 12/17/2022] Open
Abstract
Lipoproteins are some of the most abundant proteins in bacteria. With a lipid anchor to the cell membrane, they function as enzymes, inhibitors, transporters, structural proteins, and as virulence factors. Lipoproteins activate the innate immune system and have biotechnological applications. The first lipoprotein was described by Braun and Rehn in 1969. Up until recently, however, work on lipoproteins has been sluggish, in part due to the challenges of handling proteins that are anchored to membranes by covalently linked lipids or are membrane integral. Activity in the area has quickened of late. In the past 5 years, high-resolution structures of the membrane enzymes of the canonical lipoprotein synthesis pathway have been determined, new lipoprotein types have been discovered and the enzymes responsible for their synthesis have been characterized biochemically. This has led to a flurry of activity aimed at developing novel antibiotics targeting these enzymes. In addition, surface exposed bacterial lipoproteins have been utilized as candidate vaccine antigens, and their potential to act as self-adjuvanting antigens is increasingly recognized. A summary of the latest developments in lipoproteins and their synthesis, as well as how this information is being exploited for therapeutic purposes is presented here.
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Affiliation(s)
- Luke Smithers
- School of Medicine, Trinity College Dublin, Dublin, Ireland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Samir Olatunji
- School of Medicine, Trinity College Dublin, Dublin, Ireland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Martin Caffrey
- School of Medicine, Trinity College Dublin, Dublin, Ireland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
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11
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Sharma S, Zhou R, Wan L, Feng S, Song K, Xu C, Li Y, Liao M. Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins. Nat Commun 2021; 12:4687. [PMID: 34344901 PMCID: PMC8333309 DOI: 10.1038/s41467-021-24965-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/16/2021] [Indexed: 02/07/2023] Open
Abstract
Lipoproteins are important for bacterial growth and antibiotic resistance. These proteins use lipid acyl chains attached to the N-terminal cysteine residue to anchor on the outer surface of cytoplasmic membrane. In Gram-negative bacteria, many lipoproteins are transported to the outer membrane (OM), a process dependent on the ATP-binding cassette (ABC) transporter LolCDE which extracts the OM-targeted lipoproteins from the cytoplasmic membrane. Lipid-anchored proteins pose a unique challenge for transport machinery as they have both hydrophobic lipid moieties and soluble protein component, and the underlying mechanism is poorly understood. Here we determined the cryo-EM structures of nanodisc-embedded LolCDE in the nucleotide-free and nucleotide-bound states at 3.8-Å and 3.5-Å resolution, respectively. The structural analyses, together with biochemical and mutagenesis studies, uncover how LolCDE recognizes its substrate by interacting with the lipid and N-terminal peptide moieties of the lipoprotein, and identify the amide-linked acyl chain as the key element for LolCDE interaction. Upon nucleotide binding, the transmembrane helices and the periplasmic domains of LolCDE undergo large-scale, asymmetric movements, resulting in extrusion of the captured lipoprotein. Comparison of LolCDE and MacB reveals the conserved mechanism of type VII ABC transporters and emphasizes the unique properties of LolCDE as a molecule extruder of triacylated lipoproteins.
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Affiliation(s)
- Stuti Sharma
- grid.38142.3c000000041936754XDepartment of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
| | - Ruoyu Zhou
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Li Wan
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Shan Feng
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - KangKang Song
- grid.168645.80000 0001 0742 0364Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA USA ,grid.168645.80000 0001 0742 0364Cryo-EM Core Facility, University of Massachusetts Medical School, Worcester, MA USA
| | - Chen Xu
- grid.168645.80000 0001 0742 0364Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA USA ,grid.168645.80000 0001 0742 0364Cryo-EM Core Facility, University of Massachusetts Medical School, Worcester, MA USA
| | - Yanyan Li
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Maofu Liao
- grid.38142.3c000000041936754XDepartment of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
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