Crystallization and preliminary X-ray diffraction studies of choline-binding protein F from Streptococcus pneumoniae.

Choline-binding protein F (CbpF) is a modular protein that is bound to the pneumococcal cell wall through noncovalent interactions with choline moieties of the bacterial teichoic and lipoteichoic acids. Despite being one of the more abundant proteins on the surface, along with the murein hydrolases LytA, LytB, LytC and Pce, its function is still unknown. CbpF has been crystallized using the hanging-drop vapour-diffusion method at 291 K. Diffraction-quality orthorhombic crystals belong to space group P2(1)2(1)2, with unit-cell parameters a = 49.13, b = 114.94, c = 75.69 A. A SAD data set from a Gd-HPDO3A-derivatized CbpF crystal was collected to 2.1 A resolution at the gadolinium L(III) absorption edge using synchrotron radiation.