Bacterial outer-membrane polysaccharide export (OPX) proteins occupy three structural classes with selective β-barrel porin requirements for polymer secretion
Bacterial outer-membrane polysaccharide export (OPX) proteins occupy three structural classes with selective β-barrel porin requirements for polymer secretion
ABSTRACT Secretion of high-molecular-weight polysaccharides across the bacterial envelope is ubiquitous as it enhances prokaryotic survival in (a)biotic settings. Such polymers are often assembled by Wzx/Wzy- or ABC transporter-dependent schemes that implicate outer-membrane (OM) polysaccharide export (OPX) proteins in polymer translocation to the cell surface. In the social predatory bacterium Myxococcus xanthus, exopolysaccharide (EPS)-pathway WzaX, major spore coat (MASC)-pathway WzaS, and biosurfactant polysaccharide-pathway WzaB were herein found to be truncated OPX homologues of Escherichia coli Wza lacking OM-spanning α-helices. Comparative genomics across all bacteria, complemented with cryo-electron tomography cell- envelope analyses, revealed WzaX/S/B architecture to be the most common amongst three defined OPX-protein structural classes independent of periplasmic thickness. Fold-recognition and deep- learning analyses revealed the conserved M. xanthus proteins MXAN_7418/3226/1916 (encoded adjacent to WzaX/S/B) to be integral OM β-barrels, with structural homology to the poly-N-acetyl-D- glucosamine synthase-dependent pathway porin PgaA. Such porins were identified in bacteria near numerous genes for all three OPX-protein classes. Interior MXAN_7418/3226/1916 β-barrel electrostatics were found to match known properties of their associated polymers. With MXAN_3226 essential for MASC export, and MXAN_7418 absence shown herein to compromise EPS translocation, these data support a novel secretion paradigm for Wzx/Wzy-dependent pathways in which those containing an OPX component that cannot span the OM instead utilize a β-barrel porin to mediate polysaccharide transport across the OM.
Sa?di Fares、Panda Adyasha、Jolivet Nicolas Y.、Calmettes Charles、Islam Salim T.、Martinez Matthew、Mellouk Abdelkader、John Gavin、Bitazar Razieh、Sharma Gaurav、Mahanta Utkarsha、Chang Yi-Wei
Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalInstitute of Bioinformatics and Applied Biotechnology (IBAB)Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalInstitut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalInstitut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalDepartment of Biochemistry and Biophysics, Perelman School of Medicine, University of PennsylvaniaInstitut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalDepartment of Pediatrics, Division of Infectious Diseases, Children?ˉs Hospital of PhiladelphiaInstitut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Sant¨| Biotechnologie, Universit¨| du Qu¨|bec, Institut Pasteur International Network||PROTEO, the Quebec Network for Research on Protein Function Universit¨| LavalInstitute of Bioinformatics and Applied Biotechnology (IBAB)Institute of Bioinformatics and Applied Biotechnology (IBAB)Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania
微生物学分子生物学生物化学
Sa?di Fares,Panda Adyasha,Jolivet Nicolas Y.,Calmettes Charles,Islam Salim T.,Martinez Matthew,Mellouk Abdelkader,John Gavin,Bitazar Razieh,Sharma Gaurav,Mahanta Utkarsha,Chang Yi-Wei.Bacterial outer-membrane polysaccharide export (OPX) proteins occupy three structural classes with selective β-barrel porin requirements for polymer secretion[EB/OL].(2025-03-28)[2025-05-05].https://www.biorxiv.org/content/10.1101/2022.02.11.480155.点此复制
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