Structure of yeast hexokinase-B: I. Preliminary X-ray studies and subunit structure

Abstract

Initial X-ray diffraction studies of large single crystals of yeast hexokinase-B provide information on its subunit structure and show the crystals to be suitable for a high resolution structure determination. Patterson maps of the native protein crystals suggest that the two 50,000 molecular weight subunits are identical, or very nearly so, and that they are related by an approximate rather than a true diad axis; that is, one subunit is translated relative to the other by 3.6 Å along the molecular symmetry axis. This results in heterologous subunit interactions rather than the isologous interactions expected. The crystals of hexokinase are an orthorhombic space group P2 122 1, have unit cell dimensions of a = 215.2, b = 58.5, c = 90.7 A ̊ , and show a diffraction pattern to a resolution better than 2.3 Å. Two potential heavy atom derivatives are under study.