Crystallization and preliminary X-ray analysis of tetracenomycin A2 oxygenase: a flavoprotein hydroxylase involved in polyketide biosynthesis

The tcm operon in Streptomyces glaucescens encodes a group of enzymes invol ved in the synthesis of the polyketide tetracenomycin (Tcm) C that exhibits both antitumor and antibiotic activities. Here, the crystallization and pr eliminary data characterization of the tcmG gene product, Tcm A2 oxygenase, which catalyzes the triple hydroxylation of Tcm A2 to form Tcm C, are repo rted. Tcm A2 oxygenase crystallizes in two different space groups, both wit h six monomers per asymmetric unit, resulting in large unit-cell parameters . Synchrotron data have been collected from both the hexagonal and tetragon al crystal forms to 4.5 and 4.2 Angstrom, respectively. The self-rotation f unction searches in both space groups suggest the monomers assemble into a complex with D-3 symmetry.