Title of article :
Alternative Epimerization in C7N-Aminocyclitol Biosynthesis Is Catalyzed by ValD, A Large Protein of the Vicinal Oxygen Chelate Superfamily Original Research Article
Author/Authors :
Hui Xu، نويسنده , , Yirong Zhang، نويسنده , , Jongtae Yang، نويسنده , , Taifo Mahmud، نويسنده , , Linquan Bai، نويسنده , , Zixin Deng، نويسنده ,
Issue Information :
ماهنامه با شماره پیاپی سال 2009
Pages :
10
From page :
567
To page :
576
Abstract :
Gene valD, encodes a large vicinal oxygen chelate (VOC) superfamily protein, has been identified in the validamycin biosynthetic gene cluster. Inactivation of valD significantly reduced validamycin A production, which was fully restored with the full-length valD and partially restored with either N-terminal or C-terminal half by complementation. Heterologously expressed ValD catalyzed the epimerization of 2-epi-5-epi-valiolone to 5-epi-valiolone. This metalloenzyme is a homodimer with a metal ion-binding ratio of 0.73 mol/mole protein toward Fe2+, Mn2+, Ni2+, and Zn2+. Individual and combined site-directed mutations of eight putative active site residues revealed that the N-terminal H44/E107 and the C-terminal H315/E366 are more critical for the activity than the internal H130, E183, H229, and E291. Our data have established ValD as one of the largest proteins of the VOC superfamily, catalyzing an alternative epimerization for C7N-aminocyclitol biosynthesis.
Journal title :
Chemistry and Biology
Serial Year :
2009
Journal title :
Chemistry and Biology
Record number :
1159697
Link To Document :
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