2ofp

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spinqualitylabelsall models 2ofp, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of Escherichia coli ketopantoate reductase in a ternary complex with NADP+ and pantoate

Overview

Ketopantoate reductase (KPR, EC 1.1.1.169) catalyzes the NADPH-dependent, reduction of ketopantoate to pantoate, an essential step for the, biosynthesis of pantothenate (vitamin B5). Inhibitors of the enzymes of, this pathway have been proposed as potential antibiotics or herbicides., Here we present the crystal structure of Escherichia coli KPR in a, precatalytic ternary complex with NADP+ and pantoate bound, solved to 2.3, A of resolution. The asymmetric unit contains two protein molecules, each, in a ternary complex; however, one is in a more closed conformation than, the other. A hinge bending between the N- and C-terminal domains is, observed, which triggers the switch of the essential Lys176 to form a key, hydrogen bond with the C2 hydroxyl of pantoate. Pantoate forms additional, interactions with conserved residues Ser244, Asn98, and Asn180 and with, two conservatively varied residues, Asn194 and Asn241. The steady-state, kinetics of active site mutants R31A, K72A, N98A, K176A, S244A, and E256A, implicate Asn98 as well as Lys176 and Glu256 in the catalytic mechanism., Isothermal titration calorimetry studies with these mutants further, demonstrate the importance of Ser244 for substrate binding and of Arg31, and Lys72 for cofactor binding. Further calorimetric studies show that KPR, discriminates binding of ketopantoate against pantoate only with NADPH, bound. This work provides insights into the roles of active site residues, and conformational changes in substrate recognition and catalysis, leading, to the proposal of a detailed molecular mechanism for KPR activity.

About this Structure

2OFP is a Single protein structure of sequence from Escherichia coli with ACT, NAP, PAF and DIO as ligands. Active as 2-dehydropantoate 2-reductase, with EC number 1.1.1.169 Full crystallographic information is available from OCA.

Reference

Crystal structure of Escherichia coli ketopantoate reductase in a ternary complex with NADP+ and pantoate bound: substrate recognition, conformational change, and cooperativity., Ciulli A, Chirgadze DY, Smith AG, Blundell TL, Abell C, J Biol Chem. 2007 Mar 16;282(11):8487-97. Epub 2007 Jan 16. PMID:17229734

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