Motion in Hexokinase [hexok]

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Classification Known Domain Motion, Shear Mechanism [D-s-2]

Structures 1HKG Conformation 2 [ PartsList ] 2YHX Conformation 1 [ PartsList ]

Description Shear motion with XBAaba layering and prominent crossed helices at interdomain interface: Hexokinase has 3 moving layers in one domain that shift relative to 3 rigid layers in the other domain. This distinctive layering pattern is of the form XBAabx, where abx are the 3 moving layers and XBA the rigid layers. The interface between the two middle layers is where the major shear motion occurs. One layer of helices from the mobile domain (a) slides over a layer of helices from the motionless domain (A). Helices in these two layers, which in a sense form gears upon which the domains slide, are often 'crossed'. Near to the a and A layer helices, the ligand binds in the interdomain cleft . Packed onto either side of the central layers of helices (a and A) are sheets (b and B) from the mobile and motionless domains, respectively. The mobile sheet (b) forms a second moving layer, which slides over the helices, and packed onto the other face of this sheet is a third layer (x) which moves with the sheet. Symmetrical to this third moving layer (x), a third motionless layer (X) is packed onto one side of the static sheet (B). In hexokinase layer x and X are made up of helices.

Particular values describing motion Experimental Methods = x (Traditional x-ray) Creation Date = 19970822 Modification Date = 19970822

References A M Lesk and C Chothia (1984). Mechanisms of Domain Closure in Proteins. J. Mol. Biol. 174: 175-91. [Medline info for 6161375] W S Bennett, Jr and T A Steitz (1980). Structure of a complex between hexokinase A and glucose: II. Detailed comparisons of conformation and active site configuration with the native hexokinase B monomer and dimer. J. Mol. Biol. 140: 211-230. [Medline info for 6161375] W S Bennett, Jr and T A Steitz (1978). Glucose induced conformational change in yeast hexokinase. Proc. Natl. Acad. Sci. U.S.A. 75: 4848-4852. [Medline info for 6161375]

Data and Graphics Graphic-1 XABbax layering pattern (hexokinase on right) (copyright Biochemistry, 1994)

Morphs

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Best representative Morph Morph name Structure #1 Structure #2 Residues [ ] [ ]

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Copyright 1995-2005 M. Gerstein, W. Krebs, S. Flores, N. Echols, and others
Email: Mark.Gerstein _at_ yale.edu