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STRUCTURAL BASIS FOR THE ACTIVATION OF GLYCOGEN PHOSPHORYLASE-B BY ADENOSINE-MONOPHOSPHATE

TitleSTRUCTURAL BASIS FOR THE ACTIVATION OF GLYCOGEN PHOSPHORYLASE-B BY ADENOSINE-MONOPHOSPHATE
Publication TypeJournal Article
Year of Publication1991
Authors, , Withers, SG, GOLDSMITH, EJ, FLETTERICK, RJ, MADSEN, NB
JournalSCIENCE
Volume254
Pagination1367-1371
Date PublishedNOV 29
ISSN0036-8075
Abstract

The three-dimensional structure of the activated state of glycogen phosphorylase (GP) as induced by adenosine monophosphate (AMP) has been determined from crystals of pyridoxalpyrophosphoryl-GP. The same quaternary changes relative to the inactive conformation as those induced by phosphorylation are induced by AMP, although the two regulatory signals function through different local structural mechanisms. Moreover, previous descriptions of the phosphorylase active state have been extended by demonstrating that, on activation, the amino- and carboxyl-terminal domains of GP rotate apart by 5-degrees, thereby increasing access of substrates to the catalytic site. The structure also reveals previously unobserved interactions with the nucleotide that accounts for the specificity of the nucleotide binding site for AMP in preference to inosine monophosphate.