A Putative α-Helical Porin from Corynebacterium glutamicum

Ziegler, Karin; Benz, Roland; Schulz, Georg E.

doi:10.1016/j.jmb.2008.04.017

Cited by 32 publications

(29 citation statements)

References 45 publications

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“…The biogenesis and the organization of the Corynebacteriales mycomembrane are far less documented than for the LPScontaining counterpart from Gram-negative outer membranes (19)(20)(21). Notably, very few mycomembrane proteins have been structurally and functionally characterized (10,22), and secretion pathways resulting in mycomembrane association remained an enigma.…”

Section: Discussionmentioning

confidence: 99%

Identification of specific posttranslational O -mycoloylations mediating protein targeting to the mycomembrane

Carel

Marcoux

Réat

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The outer membranes (OMs) of members of the Corynebacteriales bacterial order, also called mycomembranes, harbor mycolic acids and unusual outer membrane proteins (OMPs), including those with α-helical structure. The signals that allow precursors of such proteins to be targeted to the mycomembrane remain uncharacterized. We report here the molecular features responsible for OMP targeting to the mycomembrane of Corynebacterium glutamicum, a nonpathogenic member of the Corynebacteriales order. To better understand the mechanisms by which OMP precursors were sorted in C. glutamicum, we first investigated the partitioning of endogenous and recombinant PorA, PorH, PorB, and PorC between bacterial compartments and showed that they were both imported into the mycomembrane and secreted into the extracellular medium. A detailed investigation of cell extracts and purified proteins by top-down MS, NMR spectroscopy, and site-directed mutagenesis revealed specific and well-conserved posttranslational modifications (PTMs), including O-mycoloylation, pyroglutamylation, and N-formylation, for mycomembrane-associated and -secreted OMPs. PTM site sequence analysis from C. glutamicum OMP and other O-acylated proteins in bacteria and eukaryotes revealed specific patterns. Furthermore, we found that such modifications were essential for targeting to the mycomembrane and sufficient for OMP assembly into mycolic acid-containing lipid bilayers. Collectively, it seems that these PTMs have evolved in the Corynebacteriales order and beyond to guide membrane proteins toward a specific cell compartment.Corynebacteriales | O-acylation | sequence motif | top-down proteomics | NMR

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Section: Discussionmentioning

confidence: 99%

Identification of specific posttranslational O -mycoloylations mediating protein targeting to the mycomembrane

Carel

Marcoux

Réat

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Oligomeric channels are not rare among the members of the taxon mycolata. MspA of Mycobacterium smegmatis and PorB of Corynebacterium glutamicum also form oligomeric channel structures; MspA is an octamer, whereas PorB could be a pentamer (13,68). The PorH and PorA proteins contain, presumably because of their small sizes, only a single membrane-spanning domain.…”

Section: Discussionmentioning

confidence: 99%

Reconstitution Experiments and Gene Deletions Reveal the Existence of Two-Component Major Cell Wall Channels in the Genus Corynebacterium

et al. 2010

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Two small polypeptides, PorA and PorH, are known to form cell wall channels in Corynebacterium glutamicum and in Corynebacterium efficiens. The genes coding for both polypeptides are localized in close proximity to one another between the genes coding for GroEl2 and a polyphosphate kinase (PKK2). In this study, we investigated the relationship of PorA and PorH to one another. The results suggested that the major cell wall channels of Corynebacterium glutamicum, Corynebacterium efficiens, and Corynebacterium diphtheriae need the obligatory presence of two distinct polypeptides, one of class PorA and one of class PorH, to form an active cell wall channel. Identification of genes coding for homologous proteins in the chromosome of Corynebacterium callunae suggested a similar result for this strain. Contrary to our previous reports on channel-forming proteins in these strains, a heterooligomeric structure composed of PorA and PorH is needed in all of them to form the major cell wall channel. This was concluded from complementation experiments using a porH-and porAdeficient C. glutamicum strain. The stringent necessity of proteins of either class to recover the wild-type channels was demonstrated by black lipid bilayer experiments using detergent or organic solvent extracts of the complemented porH-and porA-deficient C. glutamicum strain. The channel-forming capability of recombinant expressed, affinity-purified PorA and PorH proteins of C. glutamicum revealed that the channels consisted solely of these two components. This agreed with results obtained from a transcript coding for both channelforming components identified in C. glutamicum by Northern blot analysis and reverse transcription-PCR analysis. The transcription start point of the genes was determined by the rapid amplification of cDNA ends approach, allowing the prediction of the ؊35 and ؊10 regions of the promoter. The results demonstrate that the cell wall channels within the genus Corynebacterium may be formed by two-component oligomers.

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“…So far, the only outer-membrane proteins known to consist primarily of α-helices are the Escherichia coli Wza 1 and Corynebacterium glutamicum PorB. 2 Outer-membrane protein G (OmpG) is a β-barrel protein in the outer membrane of E. coli. The conditions under which OmpG is naturally expressed or its channel function in vivo are not known.…”

Section: Introductionmentioning

confidence: 99%

Correlation between the OmpG Secondary Structure and Its pH-Dependent Alterations Monitored by FTIR

Korkmaz-Özkan¹,

Köster²,

Kühlbrandt³

et al. 2010

Journal of Molecular Biology

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A Putative α-Helical Porin from Corynebacterium glutamicum

Cited by 32 publications

References 45 publications

Identification of specific posttranslational O -mycoloylations mediating protein targeting to the mycomembrane

Identification of specific posttranslational O -mycoloylations mediating protein targeting to the mycomembrane

Reconstitution Experiments and Gene Deletions Reveal the Existence of Two-Component Major Cell Wall Channels in the Genus Corynebacterium

Correlation between the OmpG Secondary Structure and Its pH-Dependent Alterations Monitored by FTIR

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