The Interdomain Linker of AAV-2 Rep68 Is an Integral Part of Its Oligomerization Domain: Role of a Conserved SF3 Helicase Residue in Oligomerization

• DOI: 10.1371/journal.ppat.1002764
• Publication Date: 2012-06-14T21:30:07Z
• Authors: Francisco Zarate-...; Martino Bardelli; John W. Burgner; Maria Villamil-Ja...; Kanni Das; Demet Kekilli; Jorge Mansilla-Soto; R. Michael Linden; Carlos R. Escalante
• Keywords: Linker; RNA Helicase A

The four Rep proteins of adeno-associated virus (AAV) orchestrate all aspects its viral life cycle, including transcription regulation, DNA replication, assembly, and site-specific integration the genome into human chromosome 19. All share a central SF3 superfamily helicase domain. In other members this domain is sufficient to induce oligomerization. However, in AAV (i.e. Rep40/Rep52) as shown by monomeric characteristic, not able mediate stable This observation led us hypothesize existence an yet undefined structural determinant that regulates document, we described detailed comparison between domains AAV-2 those members. analysis shows major difference residing small oligomerization sub-domain (OD) addition, secondary structure prediction linker connecting origin-binding (OBD) indicates potential form α-helices. We demonstrate mutant Rep40 constructs containing different lengths are dimers, presence ATP/ADP, larger oligomers. further identified aromatic residue (Y224) critical for oligomerization, establishing it conserved signature motif helicases. Mutation critically affects well completely abolishes ability produce infectious virus. Taken together, our data support model where residues preceding fold α-helix becomes integral part function Rep68/78 through cooperative interaction with OBD domains.