This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. D-alanylgriseoluteic acid (AGA) is a broad spectrum antibiotic produced by Pantoea agglomerans (aka Erwinia herbicola), an enterobacterial species that is known to produce a number of interesting antimicrobial compounds. P. agglomerans appears to deploy AGA to kill other microorganisms in its local environment thus enhancing its competitiveness. AGA has been shown particularly effective against gram positive organisms. Certain strains of P. agglomerans are also capable of causing serious infections in humans. Thus we are interested not only in the chemistry of AGA biosynthesis from the standpoint of assessing the development of AGA like molecules as therapeutics, but also in terms of whether inhibition of AGA production affects the virulence of P. agglomerans. AGA is a phenazine antibiotic derived from the key metabolic intermediate chorismic acid. The biosynthesis of AGA involves a large gene cluster that encodes at least 15 proteins. Several of these are similar to the core phenazine pathway enzymes (that we have previously characterized) from Pseudomonas and that are responsible for the biosynthesis of the basic phenazine backbone. Many of the other steps in AGA biosynthesis are uncharacterized or poorly characterized. The subject of this work EhpF appears to be a phenazine CoA ligase that, we speculate, activates a phenazine substrate for a condensation reaction that modifies the phenazine ring system. Determination of the structure of EhpF will permit a comparison with other CoA liagses and will facilitate the design of specific biochemical experiments.
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