4keq
Crystal structure of 4-pyridoxolactonase, 5-pyridoxolactone boundCrystal structure of 4-pyridoxolactonase, 5-pyridoxolactone bound
Structural highlights
FunctionPDLA_RHILO Involved in the degradation of pyridoxine or pyridoxamine (free, phosphate-unbound, forms of vitamin B6). Hydrolyzes 4-pyridoxolactone to 4-pyridoxic acid. Has lower activity toward N-hexanoyl-D,L-homoserine lactone, but is not active toward 5-pyridoxolactone and gamma-butyrolactone. Publication Abstract from PubMed4-Pyridoxolactonase from Mesorhizobium loti catalyzes the zinc-dependent lactone-ring hydrolysis of 4-pyridoxolactone (4PAL) to 4-pyridoxic acid (4PA) in vitamin B6 degradation pathway I. The crystal structures of 4-pyridoxolactonase and its complex with 5-pyridoxolactone (5PAL; the competitive inhibitor) were determined. The overall structure was an alphabeta/betaalpha sandwich fold, and two zinc ions were coordinated. This strongly suggested that the enzyme belongs to subclass B3 of the class B beta-lactamases. In the complex structure, the carbonyl group of 5PAL pointed away from the active site, revealing why it acts as a competitive inhibitor. Based on docking simulation with 4PAL, 4PA and a reaction intermediate, 4-pyridoxolactonase probably catalyzes the reaction through a subclass B2-like mechanism, not the subclass B3 mechanism. Structure of 4-pyridoxolactonase from Mesorhizobium loti.,Kobayashi J, Yoshikane Y, Yagi T, Baba S, Mizutani K, Takahashi N, Mikami B Acta Crystallogr F Struct Biol Commun. 2014 Apr;70(Pt 4):424-32. doi:, 10.1107/S2053230X14003926. Epub 2014 Mar 25. PMID:24699732[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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