Article

Structural characterization of CalO2: A putative orsellinic acid P450 oxidase in the calicheamicin biosynthetic pathway

Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1544, USA.
Proteins Structure Function and Bioinformatics (Impact Factor: 2.63). 01/2009; 74(1):50-60. DOI: 10.1002/prot.22131
Source: PubMed

ABSTRACT

Although bacterial iterative Type I polyketide synthases are now known to participate in the biosynthesis of a small set of diverse natural products, the subsequent downstream modification of the resulting polyketide products remains poorly understood. Toward this goal, we report the X-ray structure determination at 2.5 A resolution and preliminary characterization of the putative orsellenic acid P450 oxidase (CalO2) involved in calicheamicin biosynthesis. These studies represent the first crystal structure for a P450 involved in modifying a bacterial iterative Type I polyketide product and suggest the CalO2-catalyzed step may occur after CalO3-catalyzed iodination and may also require a coenzyme A- (CoA) or acyl carrier protein- (ACP) bound substrate. Docking studies also reveal a putative docking site within CalO2 for the CLM orsellinic acid synthase (CalO5) ACP domain which involves a well-ordered helix along the CalO2 active site cavity that is unique compared with other P450 structures.

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    • "Seven continuous open reading frames were found in this cluster. Among them, gbnA–C were considered responsible for the biosynthesis of the heptaketide frame, while gbnD–E may be responsible for post-PKS tailoring (hydroxylation , etc.; Reddick et al. 2007; Mccoy et al. 2009; Wilson et al. 2010; Ferraro et al. 2005). Here, we report the heterologous expression of gbnA–E in a ''clean'' host Streptomyces coelicolor ZM12 (Zhou et al. 2012; Li et al. 2014) to further confirm that these core genes are sufficient for the biosynthesis of galbonolides. "
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    • "Seven continuous open reading frames were found in this cluster. Among them, gbnA–C were considered responsible for the biosynthesis of the heptaketide frame, while gbnD–E may be responsible for post-PKS tailoring (hydroxylation , etc.; Reddick et al. 2007; Mccoy et al. 2009; Wilson et al. 2010; Ferraro et al. 2005). Here, we report the heterologous expression of gbnA–E in a ''clean'' host Streptomyces coelicolor ZM12 (Zhou et al. 2012; Li et al. 2014) to further confirm that these core genes are sufficient for the biosynthesis of galbonolides. "
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