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Crystallization and preliminary X‐ray crystallographic study of the Ras‐GTPase‐activating domain of human p120GAP
Author(s) -
Scheffzek Klaus,
Lautwein Alfred,
Scherer Anna,
Franken Sybille,
Wittinghofer Alfred
Publication year - 1997
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(199702)27:2<315::aid-prot17>3.0.co;2-p
Subject(s) - gtpase , gtp' , orthorhombic crystal system , crystallography , crystallization , molecule , chemistry , materials science , physics , crystal structure , biochemistry , enzyme , organic chemistry
Ras‐GTPase‐activating proteins (Ras‐GAPs) are important regulators of the biological activity of Ras within the framework of intracellular communication where GTP‐bound Ras (Ras: GTP) is a key signal transducing molecule (Trahey and McCormick, Science 238:542–545, 1987; Boguski and McCormick, Nature 366:643–654, 1993). By accelerating Ras‐mediated GTP hydrolysis, Ras‐GAPs provide an efficient means to reset the Ras‐GTPase cycle to the GDP‐bound “OFF”‐state and terminate the Ras‐mediated signal. Here we report the crystallization of the GTPase‐activating domain of the human p120GAP. The crystals belong to the orthorhombic space group symmetry P2 1 2 1 2 1 with unit cell dimensions of a = 42.2 Å, b = 55.6 Å, c = 142.2 Å, α = β = γ = 90°. Assuming a Matthews parameter of 2.2 Å 3 /Da, there is one molecule per asymmetric unit. Applying micro‐seeding techniques, we grew large single crystals that could not be obtained by other routine methods for crystal improvement. They diffracted to a resolution of approximately 3 Å using X‐rays from a rotating anode generator and to better than 1.8 Å in a synchrotron beam. Chemical cross‐linking led to reduction of the maximum resolution but to significantly increased stability against mechanical and heavy atom stress. © 1997 Wiley‐Liss, Inc.