J. Bacteriol., Jul 1996, 4150-4156, Vol 178, No. 14
Copyright © 1996, American Society for Microbiology

A newly discovered gene, tfuA, involved in the production of the ribosomally synthesized peptide antibiotic trifolitoxin

B Breil, J Borneman and EW Triplett
Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.

Trifolitoxin (TFX) is a gene-encoded, posttranslationally modified peptide antibiotic. Previously, we have shown that tfxABCDEFG from Rhizobium leguminosarum bv. trifolii T24 is sufficient to confer TFX production and resistance to nonproducing strains within a distinct taxonomic group of the alpha-proteobacteria (E. W. Triplett, B. T. Breil, and G. A. Splitter, Appl. Environ. Microbiol. 60:4163-4166, 1994). Here we describe strain Tn5-2, a Tn5 mutant of T24 defective in the production of TFX, whose insertion maps outside of the tfx cluster. It is not altered in growth compared with T24, nor does it inactivate TFX in its proximity. The wild-type analog of the mutated region of Tn5- 2 was cloned. Sequencing, transcriptional fusion mutagenesis, and subcloning were used to identify tfuA, a gene involved in TFX production. On the basis of computer analysis, the putative TfuA protein has a mass of 72.9 kDa and includes a peroxidase motif but no transmembrane domains. TFX production studies show that extra copies of the tfxABCDEFG fragment increase TFX production in a T24 background while additional copies of tfuA do not. Lysate ribonuclease protection assays suggest that tfuA does not regulate transcription of tfxA. Upstream of tfuA are two open reading frames (ORFs). The putative product of ORF1 shows high similarity to the LysR family of transcriptional regulators. The putative product of ORF2 shows high similarity to the cytosine deaminase (CodA) of Escherichia coli.

This article has been cited by other articles:

• Schmidt, E. W., Nelson, J. T., Rasko, D. A., Sudek, S., Eisen, J. A., Haygood, M. G., Ravel, J. (2005). Patellamide A and C biosynthesis by a microcin-like pathway in Prochloron didemni, the cyanobacterial symbiont of Lissoclinum patella. Proc. Natl. Acad. Sci. USA 102: 7315-7320 [Abstract] [Full Text]  
• Scupham, A. J., Dong, Y., Triplett, E. W. (2002). Role of tfxE, but Not tfxG, in Trifolitoxin Resistance. Appl. Environ. Microbiol. 68: 4334-4340 [Abstract] [Full Text]