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Publication Abstract from PubMed

DcsB, one of the enzymes encoded in the D-cycloserine (D-CS) biosynthetic gene cluster, displays a high sequence homology to arginase, which contains two manganese ions in the active site. However, DcsB hydrolyzes N(omega)-hydroxy-L-arginine, but not L-arginine, to supply hydroxyurea for the biosynthesis of D-CS. Here, the crystal structure of DcsB was determined at a resolution of 1.5 A using anomalous scattering from the manganese ions. In the crystal structure, DscB generates an artificial dimer created by the open and closed forms. Gel-filtration analysis demonstrated that DcsB is a monomeric protein, unlike arginase, which forms a trimeric structure. The active center containing the binuclear manganese cluster differs between DcsB and arginase. In DcsB, one of the ligands of the MnA ion is a cysteine, while the corresponding residue in arginase is a histidine. In addition, DcsB has no counterpart to the histidine residue that acts as a general acid/base during the catalytic reaction of arginase. The present study demonstrates that DcsB has a unique active site that differs from that of arginase.

Crystal structure of an N(omega)-hydroxy-L-arginine hydrolase found in the D-cycloserine biosynthetic pathway.,Oda K, Shimotani N, Kuroda T, Matoba Y Acta Crystallogr D Struct Biol. 2020 Jun 1;76(Pt 6):506-514. doi:, 10.1107/S2059798320004908. Epub 2020 May 29. PMID:32496212^[3]

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