Bacterial α2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome?

Budd, Aidan; Blandin, Stéphanie; Levashina, Elena A.; Gibson, Toby J.

doi:10.1186/gb-2004-5-6-r38

Cited by 78 publications

(47 citation statements)

References 59 publications

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“…Several putative host interaction factors were present in the BiG genome, including Sel1 repeat proteins, bacterial Ig-like domains, and bacterial ␣ 2 -macroglobulins; these could be critical for recognition of this bacterial strain by the host epithelium (55). A full Flp pilus gene set was present; this apparatus is known to be critical for adhesion and biofilm formation (56).…”

Section: Resultsmentioning

confidence: 99%

Genomic Features of a Bumble Bee Symbiont Reflect Its Host Environment

Martinson

Magoč

Koch

et al. 2014

Appl Environ Microbiol

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dHere, we report the genome of one gammaproteobacterial member of the gut microbiota, for which we propose the name "Candidatus Schmidhempelia bombi," that was inadvertently sequenced alongside the genome of its host, the bumble bee, Bombus impatiens. This symbiont is a member of the recently described bacterial order Orbales, which has been collected from the guts of diverse insect species; however, "Ca. Schmidhempelia" has been identified exclusively with bumble bees. Metabolic reconstruction reveals that "Ca. Schmidhempelia" lacks many genes for a functioning NADH dehydrogenase I, all genes for the highoxygen cytochrome o, and most genes in the tricarboxylic acid (TCA) cycle. "Ca. Schmidhempelia" has retained NADH dehydrogenase II, the low-oxygen specific cytochrome bd, anaerobic nitrate respiration, mixed-acid fermentation pathways, and citrate fermentation, which may be important for survival in low-oxygen or anaerobic environments found in the bee hindgut. Additionally, a type 6 secretion system, a Flp pilus, and many antibiotic/multidrug transporters suggest complex interactions with its host and other gut commensals or pathogens. This genome has signatures of reduction (2.0 megabase pairs) and rearrangement, as previously observed for genomes of host-associated bacteria. A survey of wild and laboratory B. impatiens revealed that "Ca. Schmidhempelia" is present in 90% of individuals and, therefore, may provide benefits to its host.

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Section: Resultsmentioning

confidence: 99%

Genomic Features of a Bumble Bee Symbiont Reflect Its Host Environment

Martinson

Magoč

Koch

et al. 2014

Appl Environ Microbiol

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“…The finding that ␣ 2 M-SpeB complexes protect S. pyogenes from killing by LL-37 represents a novel principle for the evasion of innate immunity and unites these lines of research. In this context, it is interesting that ␣ 2 M-like proteins were recently identified in a large number of bacterial species (27), further emphasizing the need for regulation of proteolysis also in bacteria. Notably, an ␣ 2 M homologue was not found in S. pyogenes (27), which, on the other hand, can bind ␣ 2 M via protein GRAB.…”

Section: Inactivation Of Ll-37 By ␣ 2 M-proteinase Complexes 52822mentioning

confidence: 99%

“…In this context, it is interesting that ␣ 2 M-like proteins were recently identified in a large number of bacterial species (27), further emphasizing the need for regulation of proteolysis also in bacteria. Notably, an ␣ 2 M homologue was not found in S. pyogenes (27), which, on the other hand, can bind ␣ 2 M via protein GRAB. These observations support the notion that entrapment of proteinases through ␣ 2 M and ␣ 2 M-like proteins could be a widespread mechanism to direct bacterial proteolysis against smaller substrates, such as antibacterial peptides.…”

Section: Inactivation Of Ll-37 By ␣ 2 M-proteinase Complexes 52822mentioning

confidence: 99%

α2-Macroglobulin-Proteinase Complexes Protect Streptococcus pyogenes from Killing by the Antimicrobial Peptide LL-37

Nyberg

Rasmussen

Björck

2004

Journal of Biological Chemistry

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The significant human bacterial pathogen Streptococcus pyogenes expresses GRAB, a surface protein that binds ␣ 2 -macroglobulin (␣ 2 M), a major proteinase inhibitor of human plasma. ␣ 2 M inhibits proteolysis by trapping the proteinase, which, however, still remains proteolytically active against smaller peptides that can penetrate the ␣ 2 M-proteinase complex. Here we report that SpeB, a cysteine proteinase secreted by S. pyogenes, is trapped by ␣ 2 M bound to protein GRAB. As a consequence, SpeB is retained at the bacterial surface and protects S. pyogenes against killing by the antibacterial peptide LL-37.

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“…It has so far not been possible to detect transpeptidase activity for PBP1C, suggesting that this protein may exclusively function as a transglycosylase. While the function of PBP1C in E. coli has remained unclear, some of its homologs were proposed to have specialized roles, e.g., in nitrogen fixation or the resistance against host defense mechanisms, in other organisms (15,16). Overall, peptidoglycan synthesis has been studied intensively in E. coli, but little is known about this process in other Gram-negative bacteria.…”

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confidence: 99%

Function and Localization Dynamics of Bifunctional Penicillin-Binding Proteins in Caulobacter crescentus

et al. 2014

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The peptidoglycan cell wall of bacteria is a complex macromolecule composed of glycan strands that are cross-linked by short peptide bridges. Its biosynthesis involves a conserved group of enzymes, the bifunctional penicillin-binding proteins (bPBPs), which contain both a transglycosylase and a transpeptidase domain, thus being able to elongate the glycan strands and, at the same time, generate the peptide cross-links. The stalked model bacterium Caulobacter crescentus possesses five bPBP paralogs, named Pbp1A, PbpC, PbpX, PbpY, and PbpZ, whose function is still incompletely understood. In this study, we show that any of these proteins except for PbpZ is sufficient for growth and normal morphogenesis when expressed at native or elevated levels, whereas inactivation of all five paralogs is lethal. Growth analyses indicate a central role of PbpX in the resistance of C. crescentus against the noncanonical amino acid D-alanine. Moreover, we show that PbpX and PbpY localize to the cell division site. Their recruitment to the divisome is dependent on the essential cell division protein FtsN and likely involves interactions with FtsL and the putative peptidoglycan hydrolase DipM. The same interaction pattern is observed for Pbp1A and PbpC, although these proteins do not accumulate at midcell. Our findings demonstrate that the bPBPs of C. crescentus are, to a large extent, redundant and have retained the ability to interact with the peptidoglycan biosynthetic machineries responsible for cell elongation, cytokinesis, and stalk growth. Nevertheless, they may preferentially act in specific peptidoglycan biosynthetic complexes, thereby facilitating the independent regulation of distinct growth processes.

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Bacterial α2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome?

Cited by 78 publications

References 59 publications

Genomic Features of a Bumble Bee Symbiont Reflect Its Host Environment

Genomic Features of a Bumble Bee Symbiont Reflect Its Host Environment

α2-Macroglobulin-Proteinase Complexes Protect Streptococcus pyogenes from Killing by the Antimicrobial Peptide LL-37

Function and Localization Dynamics of Bifunctional Penicillin-Binding Proteins in Caulobacter crescentus

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