Part:BBa_K4359002

Anti-HER2 Affibody- ZHER2:342

Anti HER2 Affibody- ZHER2:342 is a small 6kDa protein with high affinity for the extracellular domain of the human epidermal growth factor receptor 2 (HER2) protein.

Biology

Affibody molecules are a class of affinity ligands which are 58 residues long. They are derived from the Z domain, a variant of the B domain of staphylococcal protein A (SPA). Affibodies are generated from libraries where 13 surface-exposed amino acids of the Z domain have been randomized to achieve affinity for a target protein. They do not possess homology with immunoglobulins. Their structure consists of three anti-parallel alpha helices. Affibodies have ideal biophysical properties, including a high melting temperature and rapid and reversible folding that does not require post-translational modifications. ZHER2:342 binds with a remarkable affinity to HER2, with a Kd value of 22 pM. The ZHER2:342 affibody epitope on HER2 is at the junction of domains III and IV.

Usage

Affibodies offer many advantages over classical antibody-based protein binding agents. The small size of ZHER2:342 makes it ideal for devices that require a high affinity for HER2. It could be used in diagnostics, imaging, bioseparation or targeted delivery. ZHER2:342 does not require post-translational modifications for functionality and is soluble in aqueous solutions, making it compatible for production in chassis like E.coli. For an example of usage in a multidomain protein, see composite part (BBa_K4359006) and (BBa_K4359008).

dissociation_constant

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