Desaturases: emerging models for understanding functional diversification of diiron-containing enzymes.
Desaturases and related enzymes perform O(2)-dependent dehydrogenations initiated at unactivated C-H groups with the use of a diiron active site. Determination of the long-sought oxidized desaturase crystal structure facilitated structural comparison of the active sites of disparate diiron enzymes. Experiments on the castor desaturase are discussed that provide experimental support for a hypothesized ancestral oxidase enzyme in the context of the evolution of the diiron enzyme diverse functionality. We also summarize recent analysis of a castor mutant desaturase that provides valuable insights into the relationship of proposed substrate-binding modes with respect to a range of catalytic outcomes.
Shanklin
John
J
Department of Biology, Brookhaven National Laboratory, Upton, New York 11973, USA. shanklin@bnl.gov
Guy
Jodie E
JE
Mishra
Girish
G
Lindqvist
Ylva
Y
D000818:Animals; D001665:Binding Sites; D001671:Biochemistry / Q000379:methods; D002384:Catalysis; D020134:Catalytic Domain; D002462:Cell Membrane / Q000378:metabolism; D004798:Enzymes / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000737:chemistry*; D008954:Models, Biological; D008968:Molecular Conformation; D009154:Mutation; D013230:Stearoyl-CoA Desaturase / Q000737:chemistry* / Q000502:physiology; D013379:Substrate Specificity
D004798:Enzymes; D005227:Fatty Acids; D007501:Iron; D013230:Stearoyl-CoA Desaturase