3fla

Publication Abstract from PubMed

Two thioesterases are commonly found in natural product biosynthetic clusters, a type I thioesterase (TEI) which is responsible for removing the final product from the biosynthetic complex, and a type II thioesterase (TEII) which is believed to perform housekeeping functions such as removing aberrant units from carrier domains. We present the crystal structure and the kinetic analysis of RifR, a TEII from the hybrid NRPS/PKS rifamycin biosynthetic cluster of Amycolatopsis mediterranei. Steady-state kinetics show RifR has a preference for the hydrolysis of acyl units from the phosphopantetheinyl arm (Ppant) of the acyl carrier domain, over the hydrolysis of acyl units from the Ppant of acyl-CoAs as well as a modest preference for the decarboxylated substrate mimics acetyl-CoA and propionyl-CoA over malonyl-CoA and methylmalonyl-CoA. Multiple RifR conformations and structural similarities to other thioesterases suggest that movement of a helical lid controls access of substrates to the active site of RifR.

Structure and functional analysis of RifR, the type II thioesterase from the rifamycin biosynthetic pathway.,Claxton HB, Akey DL, Silver MK, Admiraal SJ, Smith JL J Biol Chem. 2008 Dec 22. PMID:19103602^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.