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ACS Chem Biol. 2012 Jun 15;7(6):1059-66. doi: 10.1021/cb3000265. Epub 2012 Apr 6.

Tyrosine cross-linking reveals interfacial dynamics in adeno-associated viral capsids during infection.

Author information

1
Gene Therapy Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

Abstract

Viral capsid dynamics are often observed during infectious events such as cell surface attachment, entry and genome release. Structural analysis of adeno-associated virus (AAV), a helper-dependent parvovirus, revealed a cluster of surface-exposed tyrosine residues at the icosahedral two-fold symmetry axis. We exploited the latter observation to carry out selective oxidation of Tyr residues, which yielded cross-linked viral protein (VP) subunit dimers, effectively "stitching" together the AAV capsid two-fold interface. Characterization of different Tyr-to-Phe mutants confirmed that the formation of cross-linked VP dimers is mediated by dityrosine adducts and requires the Tyr704 residue, which crosses over from one neighboring VP subunit to the other. When compared to unmodified capsids, Tyr-cross-linked AAV displayed decreased transduction efficiency in cell culture. Surprisingly, further biochemical and quantitative microscopy studies revealed that restraining the two-fold interface hinders externalization of buried VP N-termini, which contain a phospholipase A2 domain and nuclear localization sequences critical for infection. These adverse effects caused by tyrosine oxidation support the notion that interfacial dynamics at the AAV capsid two-fold symmetry axis play a role in externalization of VP N-termini during infection.

PMID:
22458529
PMCID:
PMC3376196
DOI:
10.1021/cb3000265
[Indexed for MEDLINE]
Free PMC Article

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