Atomic-resolution structure of an N5 flavin adduct in D-arginine dehydrogenase.

Guoxing Fu, Hongling Yuan, Siming Wang, Giovanni Gadda, Irene T Weber

Index: Biochemistry 50(29) , 6292-4, (2011)

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Abstract

D-Arginine dehydrogenase (DADH) catalyzes the flavin-dependent oxidative deamination of D-arginine and other D-amino acids to the corresponding imino acids. The 1.07 Å atomic-resolution structure of DADH crystallized with D-leucine unexpectedly revealed a covalent N(5) flavin adduct, instead of the expected iminoleucine product in the active site. This acyl adduct has been successfully reproduced by photoreduction of DADH in the presence of 4-methyl-2-oxopentanoic acid (ketoleucine). The iminoleucine may be released readily because of weak interactions in the binding site, in contrast to iminoarginine, converted to ketoleucine, which reacts with activated FAD to form the covalently linked acyl adduct.© 2011 American Chemical Society