Conjugative type IV secretion in Gram-positive pathogens: TraG, a lytic transglycosylase and endopeptidase, interacts with translocation channel protein TraM

Plasmid ◽  
2017 ◽  
Vol 91 ◽  
pp. 9-18 ◽  
Author(s):  
Verena Kohler ◽  
Ines Probst ◽  
Andreas Aufschnaiter ◽  
Sabrina Büttner ◽  
Lisa Schaden ◽  
...  
Keyword(s):  
Type Iv Secretion ◽  
Gram Positive ◽  
Channel Protein ◽  
Type Iv ◽  
Lytic Transglycosylase

scholarly journals A Type IV-Secretion-Like System Is Required for Conjugative DNA Transport of Broad-Host-Range Plasmid pIP501 in Gram-Positive Bacteria

2007 ◽  
Vol 189 (6) ◽  
pp. 2487-2496 ◽  
Author(s):  
Mohammad Y. Abajy ◽  
Jolanta Kopeć ◽  
Katarzyna Schiwon ◽  
Michal Burzynski ◽  
Mike Döring ◽  
...  
Keyword(s):  
Host Range ◽  
Sequence Similarity ◽  
Type Iv Secretion ◽  
Conjugative Plasmid ◽  
Computer Assisted ◽  
Transcriptional Level ◽  
Broad Host Range ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Type Iv

ABSTRACT Plasmid pIP501 has a very broad host range for conjugative transfer among a wide variety of gram-positive bacteria and gram-negative Escherichia coli. Functionality of the pIP501 transfer (tra) genes in E. coli was proven by pIP501 retrotransfer to Enterococcus faecalis (B. Kurenbach, C. Bohn, J. Prabhu, M. Abudukerim, U. Szewzyk, and E. Grohmann, Plasmid 50:86-93, 2003). The 15 pIP501 tra genes are organized in a single operon (B. Kurenbach, J. Kopeć, M. Mägdefrau, K. Andreas, W. Keller, C. Bohn, M. Y. Abajy, and E. Grohmann, Microbiology 152:637-645, 2006). The pIP501 tra operon is negatively autoregulated at the transcriptional level by the conjugative DNA relaxase TraA. Three of the 15 pIP501-encoded Tra proteins show significant sequence similarity to the Agrobacterium type IV secretion system proteins VirB1, VirB4, and VirD4. Here we report a comprehensive protein-protein interaction map of all of the pIP501-encoded Tra proteins determined by the yeast two-hybrid assay. Most of the interactions were verified in vitro by isolation of the protein complexes with pull-down assays. In conjunction with known or postulated functions of the pIP501-encoded Tra proteins and computer-assisted prediction of their cellular location, we propose a model for the first type IV-secretion-like system encoded by a conjugative plasmid from gram-positive bacteria.

scholarly journals AtlA Functions as a Peptidoglycan Lytic Transglycosylase in the Neisseria gonorrhoeae Type IV Secretion System

2007 ◽  
Vol 189 (15) ◽  
pp. 5421-5428 ◽  
Author(s):  
Petra L. Kohler ◽  
Holly L. Hamilton ◽  
Karen Cloud-Hansen ◽  
Joseph P. Dillard
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Secretion System ◽  
Type Iv Secretion ◽  
Type Iv Secretion System ◽  
Secretion Systems ◽  
Lytic Transglycosylases ◽  
Type Iv ◽  
Lytic Transglycosylase ◽  
Enzymatic Function ◽  
Type Iv Secretion Systems

ABSTRACT Type IV secretion systems require peptidoglycan lytic transglycosylases for efficient secretion, but the function of these enzymes is not clear. The type IV secretion system gene cluster of Neisseria gonorrhoeae encodes two peptidoglycan transglycosylase homologues. One, LtgX, is similar to peptidoglycan transglycosylases from other type IV secretion systems. The other, AtlA, is similar to endolysins from bacteriophages and is not similar to any described type IV secretion component. We characterized the enzymatic function of AtlA in order to examine its role in the type IV secretion system. Purified AtlA was found to degrade macromolecular peptidoglycan and to produce 1,6-anhydro peptidoglycan monomers, characteristic of lytic transglycosylase activity. We found that AtlA can functionally replace the lambda endolysin to lyse Escherichia coli. In contrast, a sensitive measure of lysis demonstrated that AtlA does not lyse gonococci expressing it or gonococci cocultured with an AtlA-expressing strain. The gonococcal type IV secretion system secretes DNA during growth. A deletion of ltgX or a substitution in the putative active site of AtlA severely decreased DNA secretion. These results indicate that AtlA and LtgX are actively involved in type IV secretion and that AtlA is not involved in lysis of gonococci to release DNA. This is the first demonstration that a type IV secretion peptidoglycanase has lytic transglycosylase activity. These data show that AtlA plays a role in type IV secretion of DNA that requires peptidoglycan breakdown without cell lysis.

scholarly journals VirB1* Promotes T-Pilus Formation in the vir-Type IV Secretion System of Agrobacterium tumefaciens

2007 ◽  
Vol 189 (18) ◽  
pp. 6551-6563 ◽  
Author(s):  
John Zupan ◽  
Cheryl A. Hackworth ◽  
Julieta Aguilar ◽  
Doyle Ward ◽  
Patricia Zambryski
Keyword(s):  
Protein Interactions ◽  
Secretion System ◽  
Type Iv Secretion ◽  
Type Iv Secretion System ◽  
Protein Protein Interactions ◽  
Additional Function ◽  
Type Iv ◽  
Lytic Transglycosylase ◽  
Peptidoglycan Cell Wall ◽  
Two Hybrid

ABSTRACT The vir-type IV secretion system of Agrobacterium is assembled from 12 proteins encoded by the virB operon and virD4. VirB1 is one of the least-studied proteins encoded by the virB operon. Its N terminus is a lytic transglycosylase. The C-terminal third of the protein, VirB1*, is cleaved from VirB1 and secreted to the outside of the bacterial cell, suggesting an additional function. We show that both nopaline and octopine strains produce abundant amounts of VirB1* and perform detailed studies on nopaline VirB1*. Both domains are required for wild-type virulence. We show here that the nopaline type VirB1* is essential for the formation of the T pilus, a subassembly of the vir-T4SS composed of processed and cyclized VirB2 (major subunit) and VirB5 (minor subunit). A nopaline virB1 deletion strain does not produce T pili. Complementation with full-length VirB1 or C-terminal VirB1*, but not the N-terminal lytic transglycosylase domain, restores T pili containing VirB2 and VirB5. T-pilus preparations also contain extracellular VirB1*. Protein-protein interactions between VirB1* and VirB2 and VirB5 were detected in the yeast two-hybrid assay. We propose that VirB1 is a bifunctional protein required for virT4SS assembly. The N-terminal lytic transglycosylase domain provides localized lysis of the peptidoglycan cell wall to allow insertion of the T4SS. The C-terminal VirB1* promotes T-pilus assembly through protein-protein interactions with T-pilus subunits.

scholarly journals Conjugative type IV secretion systems in Gram-positive bacteria

Plasmid ◽  
2013 ◽  
Vol 70 (3) ◽  
pp. 289-302 ◽  
Author(s):  
Nikolaus Goessweiner-Mohr ◽  
Karsten Arends ◽  
Walter Keller ◽  
Elisabeth Grohmann
Keyword(s):  
Type Iv Secretion ◽  
Secretion Systems ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Type Iv ◽  
Type Iv Secretion Systems

scholarly journals Type IV secretion in Gram-negative and Gram-positive bacteria

2018 ◽  
Vol 107 (4) ◽  
pp. 455-471 ◽  
Author(s):  
Elisabeth Grohmann ◽  
Peter J. Christie ◽  
Gabriel Waksman ◽  
Steffen Backert
Keyword(s):  
Type Iv Secretion ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Type Iv

scholarly journals VirB1 Orthologs from Brucella suis and pKM101 Complement Defects of the Lytic Transglycosylase Required for Efficient Type IV Secretion from Agrobacterium tumefaciens

2004 ◽  
Vol 186 (5) ◽  
pp. 1415-1422 ◽  
Author(s):  
Christoph Höppner ◽  
Zhenying Liu ◽  
Natalie Domke ◽  
Andrew N. Binns ◽  
Christian Baron
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Active Site ◽  
Plasmid Transfer ◽  
Type Iv Secretion ◽  
Secretion Systems ◽  
Heterologous Complementation ◽  
Type Iv ◽  
Lytic Transglycosylase ◽  
Brucella Suis ◽  
Type Iv Secretion Systems

ABSTRACT Type IV secretion systems mediate conjugative plasmid transfer as well as the translocation of virulence factors from various gram-negative pathogens to eukaryotic host cells. The translocation apparatus consists of 9 to 12 components, and the components from different organisms are believed to have similar functions. However, orthologs to proteins of the prototypical type IV system, VirB of Agrobacterium tumefaciens, typically share only 15 to 30% identical amino acids, and functional complementation between components of different type IV secretion systems has not been achieved. We here report a heterologous complementation in the case of A. tumefaciens virB1 defects with its orthologs from Brucella suis (VirB1s) and the IncN plasmid pKM101 (TraL). In contrast, expression of the genes encoding the VirB1 orthologs from the IncF plasmid (open reading frame 169) and from the Helicobacter pylori cag pathogenicity island (HP0523) did not complement VirB1 functions. The complementation of VirB1 activity was assessed by T-pilus formation, by tumor formation on wounded plants, by IncQ plasmid transfer, and by IncQ plasmid recipient assay. Replacement of the key active-site Glu residue by Ala abolished the complementation by VirB1 from B. suis and by TraL, demonstrating that heterologous complementation requires an intact lytic transglycosylase active site. In contrast, the VirB1 active-site mutant from A. tumefaciens retained considerable residual activity in various activity assays, implying that this protein exerts additional effects during the type IV secretion process.

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