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A protein phosphorylation switch at the conserved allosteric site in GP.

Authors :
Lin K
Rath VL
Dai SC
Fletterick RJ
Hwang PK
Source :
Science (New York, N.Y.) [Science] 1996 Sep 13; Vol. 273 (5281), pp. 1539-42.
Publication Year :
1996

Abstract

A phosphorylation-initiated mechanism of local protein refolding activates yeast glycogen phosphorylase (GP). Refolding of the phosphorylated amino-terminus was shown to create a hydrophobic cluster that wedges into the subunit interface of the enzyme to trigger activation. The phosphorylated threonine is buried in the allosteric site. The mechanism implicates glucose 6-phosphate, the allosteric inhibitor, in facilitating dephosphorylation by dislodging the buried covalent phosphate through binding competition. Thus, protein phosphorylation-dephosphorylation may also be controlled through regulation of the accessibility of the phosphorylation site to kinases and phosphatases. In mammalian glycogen phosphorylase, phosphorylation occurs at a distinct locus. The corresponding allosteric site binds a ligand activator, adenosine monophosphate, which triggers activation by a mechanism analogous to that of phosphorylation in the yeast enzyme.

Details

Language :
English
ISSN :
0036-8075
Volume :
273
Issue :
5281
Database :
MEDLINE
Journal :
Science (New York, N.Y.)
Publication Type :
Academic Journal
Accession number :
8703213
Full Text :
https://doi.org/10.1126/science.273.5281.1539