GFP Adeno-Associated Virus ( AAV-588NGR )

The capsid of adeno-associated virus is icosahedral. It is assembled by the interaction of 60 VP monomers through these rotation axes. These VP monomers can be all VP3 or composed of VP1, VP2, and VP3. The notable features of the AAV capsid surface are the two-fold concave ground, the three-fold protrusion, and the five-fold channel. The cylindrical channel connects the inside and outside of the capsid and is where the AAV DNA enters the capsid. It is involved in multiple processes such as Rep protein binding, capsid protein assembly, VP1 N-terminal exposure, and AAV virus infection. The two-fold concave ground is the thinnest part of the viral capsid. The main function of the three-fold protrusion is to recognize receptors. Specific VP subunits have been used as targets for capsid modification, such as removal of immunogenic motifs, integration of tags or fluorescent groups, and retargeting. AAV2 is a relatively mature serotype. Taking AAV2 as the backbone, in the public VP3 region, a large number of studies have shown that I-587 (VP1 amino acid number) and I-588 are the most commonly used capsid modification positions, because these two positions are located near the three-fold protrusion and can accept the insertion of peptide chains up to 34 amino acids in length without affecting encapsidation and genome packaging. Moreover, the insertion of foreign peptide chains modifies the first receptor binding motif of AAV2, ultimately giving the AAV2 variant new targeting properties.