1w4z
From Proteopedia
STRUCTURE OF ACTINORHODIN POLYKETIDE (ACTIII) REDUCTASE
Overview
We have determined the 2.5 angstroms crystal structure of an active, tetrameric Streptomyces coelicolor type II polyketide ketoreductase (actIII) with its bound cofactor, NADP+. This structure shows a Rossman dinucleotide binding fold characteristic of SDR enzymes. Of two subunits in the crystallographic asymmetric unit, one is closed around the active site. Formate is observed in the open subunit, indicating possible carbonyl binding sites of the polyketide intermediate. Unlike previous models we observe crystal contacts that may mimic the KR-ACP interactions that may drive active site opening. Based on these observations, we have constructed a model for ACP and polyketide binding. We propose that binding of ACP triggers a conformational change from the closed to the open, active form of the enzyme. The polyketide chain enters the active site and reduction occurs. The model also suggests a general mechanism for ACP recognition which is applicable to a range of protein families.
About this Structure
1W4Z is a Single protein structure of sequence from Streptomyces coelicolor. Full crystallographic information is available from OCA.
Reference
The crystal structure of the actIII actinorhodin polyketide reductase: proposed mechanism for ACP and polyketide binding., Hadfield AT, Limpkin C, Teartasin W, Simpson TJ, Crosby J, Crump MP, Structure. 2004 Oct;12(10):1865-75. PMID:15458634 Page seeded by OCA on Sat May 3 13:10:00 2008
