Uti Limited Partnership

Sui-Lam Wong

Sau-Ching Wu

Isabelle Barrette-Ng

Ken Ng

Kenneth K-s Ng

The present invention relates to a new streptavidin muteins. This mutein is binds both streptavidin binding peptide tagged and biotin or biotinylated molecules, and does so in a reversible fashion. As such, it is stable enough to allow reuse, and producible with reasonable production yield via secretion in a soluble functional state without the requirement of refolding via the tedious and expensive denaturation and renaturation processes.

Streptavidin mutein exhibiting reversible binding for biotin and streptavidin binding peptide tagged proteins

The present invention relates to a new streptavidin muteins. This mutein is The muteins are capable of oligomerization to form tetramers, with relatively strong subunit interactions, dissociation constant (K) for biotin in this mutein in the range of 10to 10M, off-rate (k) for the bound biotin in the streptavidin-biotin complex in the range of 10sec, stable enough to allow reuse, and producible producable with reasonable production yield via secretion in a soluble functional state without the requirement of refolding streptavidin via the tedious and expensive denaturation and renaturation processes.

Tetrameric streptavidin mutein with reversible biotin binding capability

The invention includes a streptavidin mutein having at least one mutation chosen to cause one or more of steric hindrance, charge repulsion, or improvement of solubility by changing interfacial hydrophobic residues to less hydrophobic or hydrophilic residues. The mutein may exist in monomeric form even in the presence of biotin, and reversibly binds to biotin. The invention also includes polynucleotides encoding such muteins, expression systems and host cells for producing such muteins. The invention also includes a method of capturing biotinylated molecules using the muteins of the invention.

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Calgary, Canada

Sui-Lam Wong