Direct FeS cluster involvement in generation of a radical in lysine 2,3-aminomutase.
Lysine 2,3-aminomutase (KAM) belongs to a class of enzymes that use FeS clusters and S-adenosyl-L-methionine to initiate radical-dependent chemistry. Selenium K-edge X-ray absorption spectroscopic analysis of KAM poised at various stages of catalysis, in the presence of selenomethionine or Se-adenosyl-L-selenomethionine, reveals that the cofactor is cleaved only in the presence of dithionite and the substrate analogue trans-4,5-dehydrolysine. A new Fourier transform peak at 2.7 A, assigned as a Se-Fe interaction, appears concomitant with this cleavage. This is the first demonstration of a direct interaction of S-adenosyl-L-methionine, or its cleavage products, with the FeS cluster in this class of enzymes.
Cosper
N J
NJ
Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556, USA.
Booker
S J
SJ
Ruzicka
F
F
Frey
P A
PA
Scott
R A
RA
D003839:Deoxyadenosines / Q000737:chemistry; D004227:Dithionite / Q000737:chemistry; D005583:Fourier Analysis; D005609:Free Radicals / Q000378:metabolism; D006868:Hydrolysis; D019751:Intramolecular Transferases / Q000737:chemistry* / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008239:Lysine / Q000031:analogs & derivatives* / Q000737:chemistry; D012645:Selenomethionine / Q000031:analogs & derivatives* / Q000737:chemistry; D013057:Spectrum Analysis; D013379:Substrate Specificity; D014965:X-Rays
D003839:Deoxyadenosines; D005609:Free Radicals; D007506:Iron-Sulfur Proteins; D004227:Dithionite; C002194:dehydrolysine; C033714:5'-deoxyadenosine; C069627:adenosylselenomethionine; D012645:Selenomethionine; D019751:Intramolecular Transferases; C021518:lysine 2,3-aminomutase; D008239:Lysine