PRELIMINARY DIFFRACTION STUDIES OF THE REGULATED FORM OF CHICKEN SRC PROTEIN TYROSINE KINASE. J. C. Williams, A. Weijland, S. A. Courtneidge1, G. Superti-Furga, and R. K. Wierenga, EMBL, Postfach 102209, D69012 Heidelberg, Germany, 1SUGEN, Redwood City, CA 94063 USA
We present here preliminary diffraction data of the regulated form of the chicken Src Protein Tyrosine Kinase. The crystals diffract beyond 2.7Å with low mosaicity (<0.2deg.) at room temperature using syncrotron radiation at beam lines BL4 and BL19 at the ESRF, Grenoble. Due to severe radiation damage, the data was collected under cryo-conditions with a substantial increase in mosaic spread (1.1deg.). The native data set is 88% complete to 2.7Å (75%-last shell) and a mercury data set is 75% complete to 3.0Å (75%-last shell). The crystals are orthorhombic (P212121) with cell constants of a=54, b=89, c=99 with one molecule per assymetric unit and a solvent content of 53%. The Rdiff between the native and the mecury data sets is 33%.
Molecular Replacement calculations have been initiated, but prove to be difficult. Cocrystallization and soaking experiments with additional heavy atom compounds as well as seleno-deriviates are underway.