Recombinant inactive core streptavidin mutants

摘要

A new biotin-bindable polypeptide is selected from avidin or streptavidin muteins that differ from the native polypeptide by at least one amino acid and have a binding affinity for biotin of less than 10<10> l/mole; the biotin-bindable polypeptide may be present as a polymeric conjugate, e.g. with another polypeptide or protein, especially bovine serum albumin. Also claimed are: (1) a nucleic acid coding for a polypeptide as above; (2) a vector containing at least one copy of a nucleic acid as in (1); and (3) a cell transformed with a vector as in (2). Also new are: (A) the use of a biotin-bindable polypeptide selected from avidin or streptavidin muteins as a regenerable system for binding biotin, where at least one amino acid of the native polypeptide is substituted and the mutein has a binding affinity for biotin of 10<5>-10<11> l/mole; and (B) a biotin-bindable regenerable solid phase coated with a streptavidin or avidin mutein having a binding affinity for biotin of 10<5>-10<11> l/mole.