Leukemia-associated RhoGEF (LARG) is a multidomain protein that relays signals from Galpha(12/13)-coupled heptahelical receptors to GTPases that regulate the cytoskeleton. To understand the molecular basis of LARG-mediated signal transduction, structural analysis of its DH/PH domains has been initiated. The LARG DH/PH domains have been overexpressed in Escherichia coli as a TEV protease-cleavable fusion protein containing maltose-binding protein and a hexahistidine tag at the N- and C-termini, respectively. Crystals of the DH/PH domains were obtained (space group C2; unit-cell parameters a = 195.5, b = 46.0, c = 75.1 A, beta = 105.0 degrees ) and xenon and NaBr derivatives were generated which should allow the structure to be determined by MIRAS.
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