Crystallization and preliminary crystallographic analysis of the catalytic module of endolysin from Cp-7 a phage infecting Streptococcus pneumoniae

摘要

As part of the life cycle of the pneumococcal phage Cp-7, the endolysin Cpl-­7 cleaves the glycosidic β1,4 bonds between N-acetylmuramic acid and N-­acetylglucosamine in the pneumococcal cell wall, resulting in bacterial lysis. Recombinant Cpl-7 was overexpressed in Escherichia coli, purified and crystallized using the vapour-diffusion method at 291 K. Diffraction-quality tetragonal crystals of the catalytic module of Cpl-7 were obtained from a mixture of PEG 3350 and sodium formate. The crystals belonged to space group I422, with unit-cell parameters a = 127.93, b = 127.93, c = 82.07 Å. Diffraction data sets were collected to 2.4 Å resolution using a rotating-anode generator.