Photocycle of the LOV-STAS Protein from the Pathogen Listeria monocytogenes.
Article first published online: 19 NOV 2012
© 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology
Photochemistry and Photobiology
Volume 89, Issue 2, pages 361–369, March/April 2013
How to Cite
Chan, R. H., Lewis, J. W. and Bogomolni, R. A. (2013), Photocycle of the LOV-STAS Protein from the Pathogen Listeria monocytogenes. Photochemistry and Photobiology, 89: 361–369. doi: 10.1111/php.12004
- Issue published online: 1 MAR 2013
- Article first published online: 19 NOV 2012
- Accepted manuscript online: 1 OCT 2012 10:48AM EST
- Manuscript Accepted: 21 SEP 2012
- Manuscript Received: 5 JUN 2012
- NSF. Grant Number: MCB-0843662
Listeria monocytogenes, a food-borne bacterial pathogen causing significant human mortality, propagates by expressing genes in response to environmental signals, such as temperature and pH. Listeria gene (lmo0799) encodes a protein homologous to the Bacillus subtilis YtvA, which has a flavin-light, oxygen or voltage (LOV) domain and a Sulfate Transporters Anti-Sigma factor antagonist (STAS) output domain that regulates transcription-initiation factor Sigma B in the bacterial stress response upon exposure to light. This could be significant for the pathogenesis of listeriosis because Sigma B has been linked to virulence of Listeria, and the Listeria Lmo0799 protein has recently been identified as a virulence factor activated by blue light. We have cloned, expressed heterologously in Escherichia coli and purified the full-length LM-LOV-STAS protein. Although it exhibits photochemical activity similar to that of YtvA, LM-LOV-STAS lacks an almost universally conserved arginine in the flavin-binding site, as well as another positively charged residue, a lysine in YtvA. The absence of these positive charges was found to destabilize retention of the flavin mononucleotide (FMN) chromophore in the LM-LOV-STAS protein, particularly at higher temperatures. The unusual sequence of the LM-LOV-STAS protein alters both spectral features and activation/deactivation kinetics, potentially expanding the sensory capacity of this LOV domain, e.g. to detect light plus cold.