Roles of the minor pseudopilins, XpsH, XpsI and XpsJ, in the formation of XpsG-containing pseudopilus in Xanthomonas campestris pv. campestris.
Due to their similarity to type IV pilus (Tfp) subunits, the pseudopilins, XpsG, -H, -I, -J and -K, have been predicted to form a pilus-like structure in the type II secretion (T2S) pathway. While overexpression of GspG can result in the formation of bundle structures, the functions of other pseudopilin are not known yet. In this study, we investigate the mutual interaction among the pseudopilins and characterize the specialized minor pseudopilin, XpsJ. By using gel filtration and Ni-NTA affinity chromatography, a linearly ordered interactive relationship is revealed among the four pseudopilins, XpsG-XpsI-XpsH-XpsJ. Notably, unlike the mutant XpsJ194 staying in the inner membrane, wild type XpsJ stayed in the outer membrane and blocked the extension of overexpressed XpsG to outside of the cell. By analogy with the Type I pilus structures, we hypothesize that the XpsH and XpsI might act as an adaptor to connect XpsJ with the major pseudopilin XpsG, and XpsJ might act as a tip to restrict the out-growth of XpsG in the pilus-like structure of the T2S pathway.
Kuo
Wei-Wen
WW
Institute of Biochemistry, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
Kuo
Hung-Wei
HW
Cheng
Chun-Chia
CC
Lai
Hsiang-Ling
HL
Chen
Ling-Yun
LY
D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism; D036781:Fimbriae Proteins / Q000737:chemistry; D010861:Fimbriae, Bacterial / Q000737:chemistry / Q000378:metabolism*; D017353:Gene Deletion; D015151:Immunoblotting; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000502:physiology*; D009154:Mutation; D009532:Nickel / Q000737:chemistry; D017830:Octoxynol / Q000494:pharmacology; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D013395:Sucrose / Q000494:pharmacology; D016959:Xanthomonas campestris / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C071567:general secretion pathway protein, Xanthomonas campestris; D036781:Fimbriae Proteins; D013395:Sucrose; D009532:Nickel; D017830:Octoxynol; D000516:alpha-Amylases