HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Klimke, W. A. Articles by Frost, L. S. Search for Related Content PubMed PubMed Citation Articles by Klimke, W. A. Articles by Frost, L. S. Agricola Articles by Klimke, W. A. Articles by Frost, L. S.

The mating pair stabilization protein, TraN, of the F plasmid is an outer-membrane protein with two regions that are important for its function in conjugation

William A. Klimke

CW405, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9

Correspondence
Laura S. Frost
laura.frost{at}ualberta.ca

F plasmid TraN (602 aa, processed to 584 aa with 22 conserved cysteines), which is essential for F plasmid conjugation, is an outer-membrane protein involved in mating pair stabilization (MPS). Unlike R100 TraN, F TraN requires OmpA in the recipient cell for efficient MPS. The authors have identified three external loops (aa 172–187, 212–220 and 281–284) in the highly divergent region from aa 164 to aa 333 as candidates for interaction with OmpA. These loops were identified using both site-directed and random TnphoA/in mutagenesis to insert epitopes (31-aa or c-myc) into TraN and monitor their effect on sensitivity to external proteases and on mating ability. TraN is a hallmark protein of F-type IV secretion systems as demonstrated by BLAST searches of the databases. The C-terminal region is highly conserved and contains five of the six completely conserved cysteines. Mutation of these residues to serine demonstrated their importance in TraN function. TraN appears to require both intra- and intermolecular disulfide bond formation for its stability and structure as demonstrated by its instability in a dsbA mutant and its aberrant migration on SDS-polyacrylamide gels under non-reducing conditions or by cross-linking with bis(sulfosuccinimidyl)suberate (BS3). Thus, F TraN appears to have two domains: the N-terminal region is involved in OmpA interaction with OmpA during MPS; and the C-terminal region, which is rich in conserved cysteine residues, is essential for conjugation.

Present address: NCBI/NIH, 6th Floor, 45 Center Drive, Bethesda, MD 20892, USA.

This article has been cited by other articles:

				M.-H. Lin and S.-T. Liu Stabilization of pSW100 from Pantoea stewartii by the F Conjugation System J. Bacteriol., May 15, 2008; 190(10): 3681 - 3689. [Abstract] [Full Text] [PDF]

				G. F. Audette, J. Manchak, P. Beatty, W. A. Klimke, and L. S. Frost Entry exclusion in F-like plasmids requires intact TraG in the donor that recognizes its cognate TraS in the recipient Microbiology, February 1, 2007; 153(2): 442 - 451. [Abstract] [Full Text] [PDF]