Crystallization and preliminary crystallographic analysis of the transpeptidase domain of penicillin-binding protein 2B from Streptococcus pneumoniae.

Penicillin-binding protein (PBP) 2B from Streptococcus pneumoniae catalyzes the cross-linking of peptidoglycan precursors that occurs during bacterial cell-wall biosynthesis. A selenomethionyl (SeMet) substituted PBP 2B transpeptidase domain was isolated from a limited proteolysis digest of a soluble form of recombinant PBP 2B and then crystallized. The crystals belonged to space group P4(3)2(1)2, with unit-cell parameters a = b = 86.39, c = 143.27 A. Diffraction data were collected to 2.4 A resolution using the BL32B2 beamline at SPring-8. The asymmetric unit contains one protein molecule and 63.7% solvent.