S-Layer Proteins

Sára, Margit; Sleytr, Uwe B.

doi:10.1128/jb.182.4.859-868.2000

Cited by 689 publications

(538 citation statements)

References 143 publications

(174 reference statements)

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“…Although the role of phagotrophy in the origin of eukaryotes demands a flexible cell surface and, therefore, the loss of murein, it does not require a strictly naked ancestral phase (see Cavalier-Smith, 2002). Thus, given the similarities between archaebacterial and posibacterial S-layers of paracrystalline globular proteins (Sara & Sleytr, 2000), it is likely that the origin of neomura involved the loss of murein and lipoprotein, but not the S-layer. I suggest that the eubacterial S-layer was converted instead into the archaebacterial glycoprotein wall.…”

Section: Origin Of the Archaebacterial Exoskeleton And Membrane Lipidsmentioning

confidence: 99%

The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification.

Cavalier‐Smith¹

2002

International Journal of Systematic and Evolutionary Microbiology

417

590

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Prokaryotes constitute a single kingdom, Bacteria, here divided into two new subkingdoms : Negibacteria, with a cell envelope of two distinct genetic membranes, and Unibacteria, comprising the new phyla Archaebacteria and Posibacteria, with only one. Other new bacterial taxa are established in a revised higher-level classification that recognizes only eight phyla and 29 classes. Morphological, palaeontological and molecular data are integrated into a unified picture of large-scale bacterial cell evolution despite occasional lateral gene transfers. Archaebacteria and eukaryotes comprise the clade neomura, with many common characters, notably obligately co-translational secretion of N-linked glycoproteins, signal recognition particle with 7S RNA and translationarrest domain, protein-spliced tRNA introns, eight-subunit chaperonin, prefoldin, core histones, small nucleolar ribonucleoproteins (snoRNPs), exosomes and similar replication, repair, transcription and translation machinery. Eubacteria (posibacteria and negibacteria) are paraphyletic, neomura having arisen from Posibacteria within the new subphylum Actinobacteria (possibly from the new class Arabobacteria, from which eukaryotic cholesterol biosynthesis probably came). Replacement of eubacterial peptidoglycan by glycoproteins and adaptation to thermophily are the keys to neomuran origins. All 19 common neomuran character suites probably arose essentially simultaneously during the radical modification of an actinobacterium. At least 11 were arguably adaptations to thermophily. Most unique archaebacterial characters (prenyl ether lipids ; flagellar shaft of glycoprotein, not flagellin ; DNA-binding protein 10b ; specially modified tRNA ; absence of Hsp90) were subsequent secondary adaptations to hyperthermophily and/or hyperacidity. The insertional origin of protein-spliced tRNA introns and an insertion in proton-pumping ATPase also support the origin of neomura from eubacteria. Molecular co-evolution between histones and DNA-handling proteins, and in novel protein initiation and secretion machineries, caused quantum evolutionary shifts in their properties in stem neomura. Proteasomes probably arose in the immediate common ancestor of neomura and Actinobacteria. Major gene losses (e.g. peptidoglycan synthesis, hsp90, secA) and genomic reduction were central to the origin of archaebacteria. Ancestral archaebacteria were probably heterotrophic, anaerobic, sulphur-dependent hyperthermoacidophiles ; methanogenesis and halophily are secondarily derived. Multiple lateral gene transfers from eubacteria helped secondary archaebacterial adaptations to mesophily and genome re-expansion. The origin from a drastically altered actinobacterium of neomura, and the immediately subsequent simultaneous origins of archaebacteria and eukaryotes, are the most extreme and important cases of T. Cavalier-Smith quantum evolution since cells began. All three strikingly exemplify De Beer's principle of mosaic evolution : the fact that, during major evolutionary transformations, some org...

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Section: Origin Of the Archaebacterial Exoskeleton And Membrane Lipidsmentioning

confidence: 99%

The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification.

Cavalier‐Smith¹

2002

International Journal of Systematic and Evolutionary Microbiology

417

590

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“…The S-layers of several pathogenic bacteria have been reported to act as virulence factors by mediating resistance to bactericidal activities (Blaser et al, 1987;Merino et al, 1994) and adhesion to extracellular matrix proteins of the host (Schneitz et al, 1993). Furthermore, S-layers can serve as molecular sieves and act as additional stability factors for the bacterial cell envelope, in both pathogenic and nonpathogenic bacteria (Sara & Sleytr, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…The assembly process of S-layer protomers is entropy-driven, and gives rise to networks of highly ordered ultrastructures that can completely cover the surface of a bacterial cell (Sara & Sleytr, 2000). Due to their location, S-layers are generally involved in the interaction between a bacterium and its environment.…”

Section: Introductionmentioning

confidence: 99%

The surface (S)-layer gene cspB of Corynebacterium glutamicum is transcriptionally activated by a LuxR-type regulator and located on a 6 kb genomic island absent from the type strain ATCC 13032

et al. 2006

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The surface (S)-layer gene region of the Gram-positive bacterium Corynebacterium glutamicum ATCC 14067 was identified on fosmid clones, sequenced and compared with the genome sequence of C. glutamicum ATCC 13032, whose cell surface is devoid of an ordered S-layer lattice. A 5·97 kb DNA region that is absent from the C. glutamicum ATCC 13032 chromosome was identified. This region includes cspB, the structural gene encoding the S-layer protomer PS2, and six additional coding sequences. PCR experiments demonstrated that the respective DNA region is conserved in different C. glutamicum wild-type strains capable of S-layer formation. The DNA region is flanked by a 7 bp direct repeat, suggesting that illegitimate recombination might be responsible for gene loss in C. glutamicum ATCC 13032. Transfer of the cloned cspB gene restored the PS2− phenotype of C. glutamicum ATCC 13032, as confirmed by visualization of the PS2 proteins by SDS-PAGE and imaging of ordered hexagonal S-layer lattices on living C. glutamicum cells by atomic force microscopy. Furthermore, the promoter of the cspB gene was mapped by 5′ rapid amplification of cDNA ends PCR and the corresponding DNA fragment was used in DNA affinity purification assays. A 30 kDa protein specifically binding to the promoter region of the cspB gene was purified. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry and peptide mass fingerprinting of the purified protein led to the identification of the putative transcriptional regulator Cg2831, belonging to the LuxR regulatory protein family. Disruption of the cg2831 gene in C. glutamicum resulted in an almost complete loss of PS2 synthesis. These results suggested that Cg2831 is a transcriptional activator of cspB gene expression in C. glutamicum.

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“…While SecA2 and SlaP are required for efficient secretion of mCherry hybrids encompassing the signal peptide and SLH domains of Sap, SlaQ functions to promote secretion of mCherry hybrids that include the C-terminal crystallization domain. Work with S-layer proteins from several different bacteria, including B. anthracis Sap, demonstrated the propensity of crystallization domains to rapidly assemble into two-dimensional paracrystalline lattices (4,5,57). Factors that promote the assembly of S-layer proteins have not yet been reported.…”

Section: Figmentioning

confidence: 99%

Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly

Nguyen-Mau

Schneewind

et al. 2015

J Bacteriol

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Bacillus anthracis vegetative forms assemble an S-layer comprised of two S-layer proteins, Sap and EA1. A hallmark of S-layer proteins are their C-terminal crystallization domains, which assemble into a crystalline lattice once these polypeptides are deposited on the bacterial surface via association between their N-terminal S-layer homology domains and the secondary cell wall polysaccharide. Here we show that slaQ, encoding a small cytoplasmic protein conserved among pathogenic bacilli elaborating S-layers, is required for the efficient secretion and assembly of Sap and EA1. S-layer protein precursors cosediment with SlaQ, and SlaQ appears to facilitate Sap assembly. Purified SlaQ polymerizes and when mixed with purified Sap promotes the in vitro formation of tubular S-layer structures. A model is discussed whereby SlaQ, in conjunction with S-layer secretion factors SecA2 and SlaP, promotes localized secretion and S-layer assembly in B. anthracis. IMPORTANCES-layer proteins are endowed with the propensity for self-assembly into crystalline arrays. Factors promoting S-layer protein assembly have heretofore not been reported. We identified Bacillus anthracis SlaQ, a small cytoplasmic protein that facilitates S-layer protein assembly in vivo and in vitro.

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S-Layer Proteins

Cited by 689 publications

References 143 publications

The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification.

The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification.

The surface (S)-layer gene cspB of Corynebacterium glutamicum is transcriptionally activated by a LuxR-type regulator and located on a 6 kb genomic island absent from the type strain ATCC 13032

Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly

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