Structure comparison of the chimeric AAV2.7m8 vector with parental AAV2

Publication date: Available online 16 December 2019Source: Journal of Structural BiologyAuthor(s): Antonette Bennett, Annahita Keravala, Victoria Makal, Justin Kurian, Brahim Belbellaa, Rangoli Aeran, Yu-Shan Tseng, Duncan Sousa, John Spear, Mehdi Gasmi, Mavis Agbandje-McKennaAbstractThe AAV2.7m8 vector is an engineered capsid with a 10-amino acid insertion in adeno-associated virus (AAV) surface variable region VIII (VR-VIII) resulting in the alteration of an antigenic region of AAV2 and the ability to efficiently transduce retina cells following intravitreal administration. Directed evolution and in vivo screening in the mouse retina isolated this vector. In the present study, we sought to identify the structural differences between a recombinant AAV2.7m8 (rAAV2.7m8) vector packaging a GFP genome and its parental serotype, AAV2, by cryo-electron microscopy (cryo-EM) and image reconstruction. The structures of rAAV2.7m8 and AAV2 were determined to 2.91 and 3.02 Å resolution, respectively. The rAAV2.7m8 amino acid side-chains for residues 219–745 (the last C-terminal residue) were interpretable in the density map with the exception of the 10 inserted amino acids. While observable in a low sigma threshold density, side-chains were only resolved at the base of the insertion, likely due to flexibility at the top of the loop. A comparison to parental AAV2 (ordered from residues 217–735) showed the structures to be similar, except at some side-chains that had different orien...

Source: Journal of Structural Biology - December 17, 2019 Category: Biology Source Type: research