2phk

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spinqualitylabelsall models 2phk, resolution 2.6Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THE CRYSTAL STRUCTURE OF A PHOSPHORYLASE KINASE PEPTIDE SUBSTRATE COMPLEX: KINASE SUBSTRATE RECOGNITION

Overview

The structure of a truncated form of the gamma-subunit of phosphorylase, kinase (PHKgammat) has been solved in a ternary complex with a, non-hydrolysable ATP analogue (adenylyl imidodiphosphate, AMPPNP) and a, heptapeptide substrate related in sequence to both the natural substrate, and to the optimal peptide substrate. Kinetic characterization of the, phosphotransfer reaction confirms the peptide to be a good substrate, and, the structure allows identification of key features responsible for its, high affinity. Unexpectedly, the substrate peptide forms a short, anti-parallel beta-sheet with the kinase activation segment, the region, which in other kinases plays an important role in regulation of enzyme, activity. This anchoring of the main chain of the substrate peptide at a, fixed distance from the gamma-phosphate of ATP explains the selectivity of, PHK for serine/threonine over tyrosine as a substrate. The catalytic core, of PHK exists as a dimer in crystals of the ternary complex, and the, relevance of this phenomenon to its in vivo recognition of dimeric, glycogen phosphorylase b is considered.

About this Structure

2PHK is a Single protein structure of sequence from Oryctolagus cuniculus with MN, ATP and GOL as ligands. Active as Phosphorylase kinase, with EC number 2.7.11.19 Full crystallographic information is available from OCA.

Reference

The crystal structure of a phosphorylase kinase peptide substrate complex: kinase substrate recognition., Lowe ED, Noble ME, Skamnaki VT, Oikonomakos NG, Owen DJ, Johnson LN, EMBO J. 1997 Nov 17;16(22):6646-58. PMID:9362479

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