Purification, crystallization and preliminary X-ray crystallographic analysis of TssL from Vibrio cholerae

The type VI secretion system (T6SS) is a macromolecular complex that is conserved in Gram-negative bacteria. The T6SS secretes effector proteins into recipient cells in a contact-dependent manner in order to accomplish cooperative and competitive interactions with the cells. Although the composition and mechanism of the T6SS have been intensively investigated across many Gram-negative bacteria, to date structural information on T6SS components from the important pathogen Vibrio cholerae has been rare. Here, the cloning, purification, crystallization and preliminary X-ray crystallographic analysis of the cytoplasmic domain of TssL, an inner membrane protein of the T6SS, from V. cholerae are reported. Diffraction data were collected to 1.5Å resolution using synchrotron radiation. The crystal belonged to the hexagonal space group P61, with unit-cell parameters a = 78.4, b = 78.4, c = 49.5Å. The successful structural characterization of TssL from V. cholerae will contribute to understanding the role of the membrane-associated subunits of the T6SS in more detail.