Format

Send to

Choose Destination
Structure. 2002 Jan;10(1):33-41.

Three-dimensional structure of phosphorylase kinase at 22 A resolution and its complex with glycogen phosphorylase b.

Author information

1
Laboratory of Molecular Biophysics, Oxford Centre for Molecular Sciences, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom. venien@biop.ox.ac.uk

Abstract

Phosphorylase kinase (PhK) integrates hormonal and neuronal signals and is a key enzyme in the control of glycogen metabolism. PhK is one of the largest of the protein kinases and is composed of four types of subunit, with stoichiometry (alphabetagammadelta)(4) and a total MW of 1.3 x 10(6). PhK catalyzes the phosphorylation of inactive glycogen phosphorylase b (GPb), resulting in the formation of active glycogen phosphorylase a (GPa) and the stimulation of glycogenolysis. We have determined the three-dimensional structure of PhK at 22 A resolution by electron microscopy with the random conical tilt method. We have also determined the structure of PhK decorated with GPb at 28 A resolution. GPb is bound toward the ends of each of the lobes with an apparent stoichiometry of four GPb dimers per (alphabetagammadelta)(4) PhK. The PhK/GPb model provides an explanation for the formation of hybrid GPab intermediates in the PhK-catalyzed phosphorylation of GPb.

PMID:
11796108
DOI:
10.1016/s0969-2126(01)00691-8
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center