1cza: Difference between revisions
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|PDB= 1cza |SIZE=350|CAPTION= <scene name='initialview01'>1cza</scene>, resolution 1.9Å | |PDB= 1cza |SIZE=350|CAPTION= <scene name='initialview01'>1cza</scene>, resolution 1.9Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand= | |LIGAND= <scene name='pdbligand=ADP:ADENOSINE-5'-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=G6P:ALPHA-D-GLUCOSE-6-PHOSPHATE'>G6P</scene>, <scene name='pdbligand=GLC:GLUCOSE'>GLC</scene> | ||
|ACTIVITY= [http://en.wikipedia.org/wiki/Hexokinase Hexokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.1 2.7.1.1] | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Hexokinase Hexokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.1 2.7.1.1] </span> | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY=[[1hkb|1HKB]], [[1hkc|1HKC]] | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1cza FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cza OCA], [http://www.ebi.ac.uk/pdbsum/1cza PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1cza RCSB]</span> | |||
}} | }} | ||
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==Overview== | ==Overview== | ||
Hexokinase I, the pacemaker of glycolysis in brain tissue, is composed of two structurally similar halves connected by an alpha-helix. The enzyme dimerizes at elevated protein concentrations in solution and in crystal structures; however, almost all published data reflect the properties of a hexokinase I monomer in solution. Crystal structures of mutant forms of recombinant human hexokinase I, presented here, reveal the enzyme monomer for the first time. The mutant hexokinases bind both glucose 6-phosphate and glucose with high affinity to their N and C-terminal halves, and ADP, also with high affinity, to a site near the N terminus of the polypeptide chain. Exposure of the monomer crystals to ADP in the complete absence of glucose 6-phosphate reveals a second binding site for adenine nucleotides at the putative active site (C-half), with conformational changes extending 15 A to the contact interface between the N and C-halves. The structures reveal distinct conformational states for the C-half and a rigid-body rotation of the N-half, as possible elements of a structure-based mechanism for allosteric regulation of catalysis. | Hexokinase I, the pacemaker of glycolysis in brain tissue, is composed of two structurally similar halves connected by an alpha-helix. The enzyme dimerizes at elevated protein concentrations in solution and in crystal structures; however, almost all published data reflect the properties of a hexokinase I monomer in solution. Crystal structures of mutant forms of recombinant human hexokinase I, presented here, reveal the enzyme monomer for the first time. The mutant hexokinases bind both glucose 6-phosphate and glucose with high affinity to their N and C-terminal halves, and ADP, also with high affinity, to a site near the N terminus of the polypeptide chain. Exposure of the monomer crystals to ADP in the complete absence of glucose 6-phosphate reveals a second binding site for adenine nucleotides at the putative active site (C-half), with conformational changes extending 15 A to the contact interface between the N and C-halves. The structures reveal distinct conformational states for the C-half and a rigid-body rotation of the N-half, as possible elements of a structure-based mechanism for allosteric regulation of catalysis. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Kirby, C.]] | [[Category: Kirby, C.]] | ||
[[Category: Liu, X.]] | [[Category: Liu, X.]] | ||
[[Category: structurally homologous domain]] | [[Category: structurally homologous domain]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:31:24 2008'' | ||
