Present address: Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD 21231, USA.
EtfA catalyses the formation of dipicolinic acid in Clostridium perfringens
Article first published online: 3 DEC 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
Volume 75, Issue 1, pages 178–186, January 2010
How to Cite
Orsburn, B. C., Melville, S. B. and Popham, D. L. (2010), EtfA catalyses the formation of dipicolinic acid in Clostridium perfringens. Molecular Microbiology, 75: 178–186. doi: 10.1111/j.1365-2958.2009.06975.x
- Issue published online: 23 DEC 2009
- Article first published online: 3 DEC 2009
- Accepted 12 November, 2009.
Dipicolinic acid (DPA) is a major component of bacterial endospores, comprising 5–15% of the spore dry weight, and is important for spore stability and resistance properties. The biosynthetic precursor to DPA, dihydro-dipicolinic acid (DHDPA), is produced by DHDPA synthase within the lysine biosynthesis pathway. In Bacillus subtilis, and most other bacilli and clostridia, DHDPA is oxidized to DPA by the products of the spoVF operon. Analysis of the genomes of the clostridia in Cluster I, including the pathogens Clostridium perfringens, Clostridium botulinum and Clostridium tetani, has shown that no spoVF orthologues exist in these organisms. DPA synthase was purified from extracts of sporulating C. perfringens cells. Peptide sequencing identified an electron transfer flavoprotein, EtfA, in this purified protein fraction. A C. perfringens strain with etfA inactivated is blocked in late stage sporulation and produces ≤ 11% of wild-type DPA levels. C. perfringens EtfA was expressed in and purified from Escherichia coli, and this protein catalysed DPA formation in vitro. The sequential production of DHDPA and DPA in C. perfringens appears to be catalysed by DHDPA synthase followed by EtfA. Genome sequence data and the taxonomy of spore-forming species suggest that this may be the ancestral mechanism for DPA synthesis.