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 Bannam, T. L. Articles by Rood, J. I. Search for Related Content PubMed PubMed Citation Articles by Bannam, T. L. Articles by Rood, J. I. Agricola Articles by Bannam, T. L. Articles by Rood, J. I.

Identification of structural and functional domains of the tetracycline efflux protein TetA(P) from Clostridium perfringens

Department of Microbiology, Monash University, Clayton, Victoria 3168, Australia¹

Author for correspondence: Julian I. Rood. Tel: +61 3 9905 4825. Fax: +61 3 9905 4811. e-mail: julian.rood{at}med.monash.edu.au

The Clostridium perfringens tetracycline-resistance protein, TetA(P), is an integral inner-membrane protein that mediates the active efflux of tetracycline from the cell. TetA(P) acts as an antiporter, presumably transporting a divalent cation–tetracycline complex in exchange for a proton, and is predicted to have 12 transmembrane domains (TMDs). Two glutamate residues that are located in predicted TMD 2 were previously shown to be required for the active efflux of tetracycline by TetA(P). To identify additional residues that are required for the structure or function of TetA(P), a random mutagenesis approach was used. Of the 61 tetracycline-susceptible mutants that were obtained in Escherichia coli, 31 different derivatives were shown to contain a single amino acid change that resulted in reduced tetracycline resistance. The stability of the mutant TetA(P) proteins was examined by immunoblotting and 19 of these strains were found to produce a detectable TetA(P) protein. The MIC of these derivatives ranged from 2 to 15 µg tetracycline ml^-1, compared to 30 µg tetracycline ml^-1 for the wild-type. The majority of these mutants clustered into three potential loop regions of the TetA(P) protein, namely the cytoplasmic loops 2–3 and 4–5, and loop 7–8, which is predicted to be located in the periplasm in E. coli. It is concluded that these regions are of functional significance in the TetA(P)-mediated efflux of tetracycline from the bacterial cell.

Keywords: tetracycline, resistance, efflux, transmembrane domains, Clostridium perfringens

Abbreviations: MFS, major facilitator superfamily; TMD, transmembrane domain

This article has been cited by other articles:

				K. A. Kazimierczak, M. T. Rincon, A. J. Patterson, J. C. Martin, P. Young, H. J. Flint, and K. P. Scott A New Tetracycline Efflux Gene, tet(40), Is Located in Tandem with tet(O/32/O) in a Human Gut Firmicute Bacterium and in Metagenomic Library Clones Antimicrob. Agents Chemother., November 1, 2008; 52(11): 4001 - 4009. [Abstract] [Full Text] [PDF]

				S. K. Ahn, K. Tahlan, Z. Yu, and J. Nodwell Investigation of Transcription Repression and Small-Molecule Responsiveness by TetR-Like Transcription Factors Using a Heterologous Escherichia coli-Based Assay J. Bacteriol., September 15, 2007; 189(18): 6655 - 6664. [Abstract] [Full Text] [PDF]

				T. L. Bannam, P. A. Johanesen, C. L. Salvado, S. J. A. Pidot, K. A. Farrow, and J. I. Rood The Clostridium perfringens TetA(P) efflux protein contains a functional variant of the Motif A region found in major facilitator superfamily transport proteins Microbiology, January 1, 2004; 150(1): 127 - 134. [Abstract] [Full Text] [PDF]

				P. A. Johanesen, D. Lyras, T. L. Bannam, and J. I. Rood Transcriptional Analysis of the tet(P) Operon from Clostridium perfringens J. Bacteriol., December 15, 2001; 183(24): 7110 - 7119. [Abstract] [Full Text] [PDF]