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These have the ability to act as specific ligands for the proteins of interest that are needed when the fusion of proteins to polypeptide tags is impossible or carries no advantage and thus, build affinity columns as is in the case of the production of biopharmaceuticals. They were immobilized on an agarose matrix and the columns were practical and had a high degree of selectivity. In addition to this, antibodies and non-immunoglobin proteins can be purified by using affitins via affinity chromatography. Due to their small size and high solubility, they can be easily produced in large amounts using bacterial expression systems.

Affitins are strongly modified reagents that are extremophilic since they are found in Archae like Sac7d which is a hyperthermostable protein. They are artificially binding proteins with extremely high affinity, small size, low structural complexity. They have two different modes of binding. One requires just a flat surface whereas the second mode of binding requires a flat surface and two short loops.They are thermally and chemically stable reagents and their stability can be further increased by using mutation or grafting techniques. Other methods of stabilizing them include the use of sequence elements from other proteins that belong to the same family, switching a binding surface, and thus, have longer binding capacities. This was done by grafting the binding surface of D1Sac7d onto Sso7d, which is more stable, and by introducing point mutations previously identified as stabilizing for WT Sso7d.

To summarize, Affitins are ideal reagents for affinity chromatography because they are durable, highly selective, cost effective, resistant to extreme alkaline pH and chemically and thermally stable. They also play a significant role in biotechnological and clinical applications. Affitin use provides important and useful methods for in vivo and in vitro analysis of protein structure.