Structure and Functional Analysis of RifR, the Type II Thioesterase from the Rifamycin Biosynthetic Pathway

Journal Article · Mon Mar 16 04:00:00 EDT 2009 · J. Biol. Chem.

DOI:https://doi.org/10.1074/jbc.M808604200· OSTI ID:1005484

Claxton, Heather B; Akey, David L; Silver, Monica K; Admiraal, Suzanne J; Smith, Janet L

Two thioesterases are commonly found in natural product biosynthetic clusters, a type I thioesterase that is responsible for removing the final product from the biosynthetic complex and a type II thioesterase that 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 type II thioesterase from the hybrid nonribosomal peptide synthetases/polyketide synthase rifamycin biosynthetic cluster of Amycolatopsis mediterranei. Steady-state kinetics show that RifR has a preference for the hydrolysis of acyl units from the phosphopantetheinyl arm of the acyl carrier domain over the hydrolysis of acyl units from the phosphopantetheinyl arm 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.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE
• OSTI ID: 1005484
• Journal Information: J. Biol. Chem., Journal Name: J. Biol. Chem. Journal Issue: (8) ; 02, 2009 Vol. 284; ISSN JBCHA3; ISSN 0021-9258
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL STRUCTURE
FUNCTIONAL ANALYSIS
HYDROLYSIS
KINETICS
PEPTIDES
SUBSTRATES