1HKC

RECOMBINANT HUMAN HEXOKINASE TYPE I COMPLEXED WITH GLUCOSE AND PHOSPHATE

Summary for 1HKC

• Entry DOI: 10.2210/pdb1hkc/pdb
• Descriptor: D-GLUCOSE 6-PHOSPHOTRANSFERASE, beta-D-glucopyranose, PHOSPHATE ION, ... (5 entities in total)
• Functional Keywords: phosphotransferase, glycolysis, allosteric enzyme, glucose, phosphate
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 103072.35

Authors

Aleshin, A.E.,Honzatko, R.B. (deposition date: 1998-07-01, release date: 1998-11-11, Last modification date: 2024-05-22)

Primary citation

Aleshin, A.E.,Zeng, C.,Bartunik, H.D.,Fromm, H.J.,Honzatko, R.B.
Regulation of hexokinase I: crystal structure of recombinant human brain hexokinase complexed with glucose and phosphate.
J.Mol.Biol., 282:345-357, 1998

PubMed Abstract: Hexokinase I, the pacemaker of glycolysis in brain tissue and red blood cells, is comprised of two similar domains fused into a single polypeptide chain. The C-terminal half of hexokinase I is catalytically active, whereas the N-terminal half is necessary for the relief of product inhibition by phosphate. A crystalline complex of recombinant human hexokinase I with glucose and phosphate (2.8 A resolution) reveals a single binding site for phosphate and glucose at the N-terminal half of the enzyme. Glucose and phosphate stabilize the N-terminal half in a closed conformation. Unexpectedly, glucose binds weakly to the C-terminal half of the enzyme and does not by itself stabilize a closed conformation. Evidently a stable, closed C-terminal half requires either ATP or glucose 6-phosphate along with glucose. The crystal structure here, in conjunction with other studies in crystallography and directed mutation, puts the phosphate regulatory site at the N-terminal half, the site of potent product inhibition at the C-terminal half, and a secondary site for the weak interaction of glucose 6-phosphate at the N-terminal half of the enzyme. The relevance of crystal structures of hexokinase I to the properties of monomeric hexokinase I and oligomers of hexokinase I bound to the surface of mitochondria is discussed.

PubMed: 9735292
DOI: 10.1006/jmbi.1998.2017

Experimental method

X-RAY DIFFRACTION (2.8 Å)