Crystallization and preliminary X-ray analysis of native and selenomethionine 2-hydroxybiphenyl 3-monooxygenase

2-hydroxybiphenyl 3-monooxygenase (HbpA; EC 1.14.13.44) from Pseudomonas azelaica HBP1 was produced in Escherichia coli both as native and SeMet-labelled protein. The two enzymes were purified to homogeneity and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 108.6, b = 196.8, c = 79.3 A, beta = 97.7 degrees for the native protein and a = 108.3, b = 196.8, c = 79.0 A, beta = 97.8 degrees for SeMet HbpA. Crystal-packing considerations led to the assumption of two HbpA subunits per asymmetric unit, which corresponds to a V(M) value of 3.3 A(3) Da(-1) and a solvent content of 62%. The crystals were radiation-sensitive and only had a lifespan of about 120 s when exposed to synchrotron radiation on an undulator beamline. To obtain complete data sets, data were collected from 23 native and 26 derivative crystals. The high-resolution limit was 2.0 A for native and 2.25 A for SeMet HbpA.