Spectrophotometric Methods for the Determination of Superantigen Structure and Stability

An important characteristic of superantigens (SAgs) is their high structural stability. For instance, it is well known that staphylococcal enterotoxins are stable enough to traverse the stomach while retaining their biological activity. Despite this high stability, structural flexibility may be a very important parameter to control their functions such as recognition of certain T-cell receptor (TCR) Vβ -chains. The biological properties of SAgs are well-characterized and most residues involved in their functional interactions such as binding to major histocompatibility complex (MHC) class II or TCR have been identified (1 ). However, those residues often also have important roles for their stability (2 ).