Journal
JOURNAL OF STRUCTURAL BIOLOGY
Volume 213, Issue 4, Pages -Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jsb.2021.107795
Keywords
Stability; cryo-EM; AAV-TT; Receptor binding; Antibody binding; Glycan array
Funding
- NIH [S10 OD018142-01, GM082946, S10 RR025080-01, U24 GM116788]
- University of Florida COM
- King's Commercialization Institute
- MRC [MR/S009302/1]
Ask authors/readers for more resources
AAV-TT, a variant of AAV2, shows higher neurotropism compared to wild type AAV2 and is currently being evaluated for central nervous system applications. It differs from AAV2 by 14 amino acids, including R585S and R588T, which have been shown to be essential for heparan sulfate binding of AAV2.
Adeno-associated viruses (AAV) are utilized as gene transfer vectors in the treatment of monogenic disorders. A variant, rationally engineered based on natural AAV2 isolates, designated AAV-True Type (AAV-TT), is highly neurotropic compared to wild type AAV2 in vivo, and vectors based on it, are currently being evaluated for central nervous system applications. AAV-TT differs from AAV2 by 14 amino acids, including R585S and R588T, two residues previously shown to be essential for heparan sulfate binding of AAV2. The capsid structures of AAVTT and AAV2 visualized by cryo-electron microscopy at 3.4 and 3.0 angstrom resolution, respectively, highlighted structural perturbations at specific amino acid differences. Differential scanning fluorimetry (DSF) performed at different pH conditions demonstrated that the melting temperature (T-m) of AAV2 was consistently similar to 5 degrees C lower than AAV-TT, but both showed maximal stability at pH 5.5, corresponding to the pH in the late endosome, proposed as required for VP1u externalization to facilitate endosomal escape. Reintroduction of arginines at positions 585 and 588 in AAV-TT caused a reduction in T-m, demonstrating that the lack of basic amino acids at these positions are associated with capsid stability. These results provide structural and thermal annotation of AAV2/AAV-TT residue differences, that account for divergent cell binding, transduction, antigenic reactivity, and transduction of permissive tissues between the two viruses. Specifically, these data indicate that AAV-TT may not utilize a glycan receptor mediated pathway to enter cells and may have lower antigenic properties as compared to AAV2.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available