Crystallization and preliminary X-ray crystallographic studies on maltosyltransferase from Thermotoga maritima

Thermotoga maritima maltosyltransferase (MTase) is a 73.7 kDa molecular weight amylolytic enzyme which catalyzes the transfer of maltosyl units from maltodextrins or starch to suitable acceptors. Crystals of recombinant MTase have been obtained by the hanging-drop vapour-diffusion method using ammonium phosphate as a precipitating agent. The crystals belong to space group P4(1)22 or its enantiomorph P4(3)22, with unit-cell parameters a = b = 148.7, c = 106.7 A. The asymmetric unit appears to contain one subunit, corresponding to a very low packing density of 4.0 A(3) Da(-1). The crystals diffract X-rays to at least 2.4 A resolution on a synchrotron-radiation source.