A protein phosphorylation switch at the conserved allosteric site in GP.Lin, K., Rath, V.L., Dai, S.C., Fletterick, R.J., Hwang, P.K.
(1996) Science 273: 1539-1542
- PubMed: 8703213
- PubMed Abstract:
- Mechanism of Regulation in Yeast Glycogen Phosphorylase
Lin, K.,Hwang, P.K.,Fletterick, R.J.
(1995) J.Biol.Chem. 270: 26833
- Purification and Crystallization of Glycogen Phosphorylase from Saccharomyces Cerevisiae
Rath, V.L.,Hwang, P.K.,Fletterick, R.J.
(1992) J.Mol.Biol. 225: 1027
- Parallel Evolution in Two Homologues of Phosphorylase
Rath, V.L.,Fletterick, R.J.
(1994) Nat.Struct.Mol.Biol. 1: 681
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 enzym ...
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.
Department of Biochemistry and Biophysics, University of California at San Francisco, 513 Parnassus, San Francisco, CA 94143, USA.