Glycation of aspartate aminotransferase and conformational flexibility.
Glycation of proteins alters biological function and changes cellular processes. Our study investigated the conformational changes that accompany glycation using the cardiac aspartate aminotransferase (cAAT). We examined the effects of brief and prolonged exposure of cAAT to glyceraldehyde (Glyc) and ribose 5-phosphate (R5P). When cAAT was briefly incubated (3.5 h) with Glyc (500 microM) or R5P (5 mM) at 37 degrees C, cAAT activity and 1-anilinonaphthalene 8-sulfonate (ANS) binding increased relative to control. After prolonged incubation (64 h) with Glyc (500 microM) or R5P (5 mM) at 37 degrees C, activity and ANS binding decreased relative to control. Furthermore, upon prolonged incubation of cAAT with 500 microM Glyc (14.5 h) or 2 mM R5P (64.25 h) at 37 degrees C, the denaturation curves shifted to the right relative to control. We conclude that upon brief incubation with Glyc and R5P, cAAT exhibited a more open and flexible structure and upon prolonged incubation, a more rigid structure.
Seidler
N W
NW
Department of Biochemistry, University of Health Sciences, 1750 Independence Avenue, Kansas City, Missouri, 64106, USA. nseidler@fac1.uhs.edu
Seibel
I
I
D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D000818:Animals; D001219:Aspartate Aminotransferases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D004795:Enzyme Stability; D005456:Fluorescent Dyes / Q000378:metabolism; D005470:Fluorometry; D005985:Glyceraldehyde / Q000378:metabolism* / Q000494:pharmacology; D006031:Glycosylation; D009206:Myocardium / Q000201:enzymology; D018583:Pliability; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D012267:Ribosemonophosphates / Q000378:metabolism* / Q000494:pharmacology; D013696:Temperature
D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D012267:Ribosemonophosphates; D005985:Glyceraldehyde; C031626:ribose-5-phosphate; C027132:1-anilino-8-naphthalenesulfonate; D001219:Aspartate Aminotransferases