Structure of the staphylococcal enterotoxin B vaccine candidate S19 showing eliminated superantigen activity

Four mutations (N23A, Y90A, R110A and F177A) were introduced into S19, a vaccine candidate for staphylococcal enterotoxin B (SEB), resulting in a lower binding affinity towards the T-cell receptor beta chain (TCB) and reducing its superantigen activity. The structure of S19 was solved and was superposed on the native or complex structure of SEB. In the superposition model, mutations that were introduced seemed to reduce the number of hydrogen bonds at the SEB – TCB interface. S19 also displayed an unexpected structural change around the flexible-loop region owing to the Y90A mutation. This local structural change provided evidence that the mutated form of S19 could have a lower affinity for major histocompatibility complex (MHC) class II than wild-type SEB.

Source: Acta Crystallographica Section F - October 20, 2017 Category: Biochemistry Authors: Jeong, W.H. Song, D.H. Hur, G.H. Jeong, S.T. Tags: SEB staphylococcal enterotoxin B T-cell receptor beta chain recombinant protein vaccines bacterial superantigens research communications Source Type: research