PRODUCTION OF RECOMBINANT POLYPEPTIDES OF GROUP G STREPTOCOCCUS AND ANALYSIS OF THEIR ABILITY TO BIND HUMAN SERUM ALBUMIN
Many Gram-positive bacteria produce surface proteins that bind human serum albumin (HSA). Th ey can be used as affinity reagents for the isolation of HSA from serum and receiving it in a highly purified condition; and as a fusion partners with recombinant proteins to facilitate their affi nity purifi cation. Recombinant HSA-binding proteins can be used in the laboratory diagnostics, for example for the quantitative detection of HSA in various biological fluids. Furthermore, they can find an application in proteomics for the removal of HSA from human serum. Therefore, it is necessary to create a reagent, binding HSA with high specifi city. This study is devoted to synthesis of recombinant polypeptides hav ing high capability to exclusively bind HSA. The recombinant polypeptides A1, A2 and A3 are derived from Streptococcus group G, extracted from cow’s milk. They have high HSA-binding activity. However, A1 polypeptide, containing the areas N, E1, E2, region of the two HSA-binding GA modules and W region, has the highеst molecular weight, and the highest affinity towards HSA. It was shown that the af finity of the polypeptide towards HSA both depends on the structure and size of the entire polypeptide.