Structure of the Yersinia pestis tip protein LcrV refined to 1.65 Å resolution

摘要

The human pathogen Yersinia pestis requires the assembly of the type III secretion system (T3SS) for virulence. The structural component of the T3SS contains an external needle and a tip complex, which is formed by LcrV in Y. pestis. The structure of an LcrV triple mutant (K40A/D41A/K42A) in a C273S background has previously been reported to 2.2 Å resolution. Here, the crystal structure of LcrV without the triple mutation in a C273S background is reported at a higher resolution of 1.65 Å. Overall the two structures are similar, but there are also notable differences, particularly near the site of the triple mutation. The refined structure revealed a slight shift in the backbone positions of residues Gly28–Asn43 and displayed electron density in the loop region consisting of residues Ile46–Val63, which was disordered in the original structure. In addition, the helical turn region spanning residues Tyr77–Gln95 adopts a different orientation.