ALFA-tag is a small and stable α-helical structure composed of 15 amino acids. ALFA-tag is highly hydrophilic and can be placed at the N-terminus, C-terminus, or between two independently folded domains of the target protein without affecting the function of the protein. ALFA-tag is widely used as an epitope tag and is used for the detection and manipulation of proteins in living cells[1].
References:
[1]. G?tzke H, et al. The ALFA-tag is a highly versatile tool for nanobody-based bioscience applications[J]. Nature communications, 2019, 10(1): 4403.