Temperature Control of Biotin Binding and Release with A Streptavidin-Poly(N-isopropylacrylamide) Site-Specific Conjugate

• DOI: 10.1021/bc980108s
• Publication Date: 2002-07-26T05:30:26Z
• Authors: Zhongli Ding; Cynthia J. Long; Yoshiki Hayashi; Esma V. Bulmus; Allan S. Hoffman; Patrick S. Stayton
• Keywords: Streptavidin; Conjugate; Poly(N-isopropylacrylamide); Conformational change; Residue (chemistry)

The many laboratory and diagnostic applications utilizing streptavidin as a molecular adaptor rely on its high affinity essentially irreversible interaction with biotin. However, there are situations where recovery of the biotinylated molecules is desirable. We have previously shown that poly(N-isopropylacrylamide) (PNIPAAm), temperature-sensitive polymer, can reversibly block biotin association polymer's conformation changes at lower critical solution temperature (LCST). Here, we constructed streptavidin−PNIPAAm conjugate which able to bind room or release bound 37 °C. repeatedly cycled through LCST. A genetically engineered mutant, E116C, has only one cysteine residue, was conjugated site specifically via sulfhydryl groups PNIPAAm pendent sulfhydryl-reactive vinyl sulfone groups. conjugation near tryptophan 120 forms van der Waals contact important in generating large binding free energy. temperature-induced conformational change polymer position 116 may lead structural region responsible for reversible between streptavidin.