Structure of the month - January 2009


Figure 1. Crystal structures of the monomer (left) and biological active crystallographic trimer (right) of Sf6 TSPΔN. (PDB code 2VBK).


Figure 2. Localization of the Endorhamnosidase Active Site of Sf6 TSPΔN (PDB code 2VBM).

(A) Difference electron density (contoured at 3σ) observed in a complex of the protein with one repeating unit (RU) of an O-antigen hydrolysis product (a-L-Rhap-(1-3)-b-L-GlcpNAc -(1-2)-a-L-Rhap-(1-2)-a-L-Rhap). Glu293 (chain C) and Asp247 (chain A) belong to the binding site.

(C) An octasaccharide (2 RU) modeled into the binding site with its reducing end reaching the catalytic residues Asp399 and Glu366, which lie on different chains, as indicated (right). Bridging water molecules are colored purple.


Table 1. Summary of data collection and refinement statistics of Sf6 TSPΔN, and of the Sf6 TSPΔN-tetrasaccharide complex.