The putative lytic transglycosylase VirB1 from Brucella suis interacts with the type IV secretion system core components VirB8, VirB9 and VirB11.
VirB1-like proteins are believed to act as lytic transglycosylases, which facilitate the assembly of type IV secretion systems via localized lysis of the peptidoglycan. This paper presents the biochemical analysis of interactions of purified Brucella suis VirB1 with core components of the type IV secretion system. Genes encoding VirB1, VirB8, VirB9, VirB10 and VirB11 were cloned into expression vectors; the affinity-tagged proteins were purified from Escherichia coli, and analyses by gel filtration chromatography showed that they form monomers or homo-multimers. Analysis of protein-protein interactions by affinity precipitation revealed that VirB1 bound to VirB9 and VirB11. The results of bicistron expression experiments followed by gel filtration further supported the VirB1-VirB9 interaction. Peptide array mapping identified regions of VirB1 that interact with VirB8, VirB9 and VirB11 and underscored the importance of the C-terminus, especially for the VirB1-VirB9 interaction. The binding sites were localized on a structure model of VirB1, suggesting that different portions of VirB1 may interact with other VirB proteins during assembly of the type IV secretion machinery.
Höppner
Christoph
C
Ludwig-Maximilians-Universität, Department Biologie I, Bereich Mikrobiologie, Maria-Ward-Str. 1a, D-80638 München, Germany.
Carle
Anna
A
Ludwig-Maximilians-Universität, Department Biologie I, Bereich Mikrobiologie, Maria-Ward-Str. 1a, D-80638 München, Germany.
Sivanesan
Durga
D
McMaster University, Department of Biology, 1280 Main St West, Hamilton, ON, Canada LS8 4K1.
Hoeppner
Sabine
S
Ludwig-Maximilians-Universität, Gene Center, Feodor-Lynen Str. 25, D-81377 München, Germany.
Baron
Christian
C
McMaster University, Department of Biology, 1280 Main St West, Hamilton, ON, Canada LS8 4K1.|Ludwig-Maximilians-Universität, Department Biologie I, Bereich Mikrobiologie, Maria-Ward-Str. 1a, D-80638 München, Germany.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D041021:Brucella suis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors; D016695:Glycosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding
D001426:Bacterial Proteins; D016695:Glycosyltransferases