In situ proteolysis, crystallization and preliminary X-ray diffraction analysis of a VHH that binds listeria internalin B.

ABSTRACT: The variable region of camelid heavy-chain antibodies produces the smallest known antibody fragment with antigen-binding capability (a VHH). The VHH R303 binds internalin B (InlB), a virulence factor expressed by the pathogen Listeria monocytogenes. InlB is critical for initiation of Listeria infection, as it binds a receptor (c-Met) on epithelial cells, triggering the entry of bacteria into host cells. InlB is surface-exposed and is required for virulence, hence a VHH targeting InlB has potential applications for pathogen detection or therapeutic intervention. Here, the expression, purification, crystallization and X-ray diffraction of R303 are reported. Crystals of R303 were obtained following in situ proteolysis with trypsin. Gel filtration and SDS-PAGE revealed that trypsin removed the C-terminal tag region of R303, facilitating crystal formation. Crystals of R303 diffracted to 1.3?Å resolution and belonged to the monoclinic space group P2?, with unit-cell parameters a=46.4, b=31.2, c=74.8?Å, ?=93.8°. The crystals exhibited a Matthews coefficient of 1.95?Å3?Da(-1) with two molecules in the asymmetric unit.

SUBMITTER: Huh I 

PROVIDER: S-EPMC4231859 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature