Conformation of Leu-Arg-Arg-Ala-Ser-Leu-Gly bound in the active site of adenosine cyclic 3',5'-phosphate dependent protein kinase.
Studies utilizing NMR spectroscopy have shown that adenosine cyclic 3',5'-phosphate dependent protein kinase (A-kinase) probably binds Leu-Arg-Arg-Ala-Ser-Leu-Gly (peptide 1) in one of two extended coil conformations (A or B). The relative reactivities of a series of N-methylated peptides based on the structure of peptide 1 might, therefore, be related to how well each can assume the A or B conformation. From estimates of the magnitude of steric interactions that would be induced by N-methylation of an amide in peptide 1 that is locked in either conformation, the ability of each peptide to form that conformation was predicted. The ability of A-kinase to catalyze phosphorylation of the N-methylated peptides correlated well with the ability of each peptide to form conformation A, but not conformation B. In accord with these findings, the reactivity of an unreactive N-methylated peptide was partially restored by a second change, which allowed the peptide to assume conformation A. These results suggest that, when bound in the enzymatic active site, peptide 1 has a conformation that resembles structure A much more closely than structure B.
Bramson
H N
HN
Laboratory of Bioorganic Chemistry and Biochemistry, Rockefeller University, New York, New York 10021.
Thomas
N E
NE
Miller
W T
WT
Fry
D C
DC
Mildvan
A S
AS
Kaiser
E T
ET
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003196:Computer Graphics; D007700:Kinetics; D008958:Models, Molecular; D009206:Myocardium / Q000201:enzymology; D009842:Oligopeptides / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011494:Protein Kinases / Q000378:metabolism*
D009842:Oligopeptides; D011494:Protein Kinases