title: Details of ssDNA annealing revealed by an HSV-1 ICP8-ssDNA binary complex.
abstract: Infected cell protein 8 (ICP8) from herpes simplex virus 1 was first identified as a single-strand (ss) DNA-binding protein. It is essential for, and abundant during, viral replication. Studies in vitro have shown that ICP8 stimulates model replication reactions, catalyzes annealing of complementary ssDNAs and, in combination with UL12 exonuclease, will catalyze ssDNA annealing homologous recombination. DNA annealing and strand transfer occurs within large oligomeric filaments of ssDNA-bound ICP8. We present the first 3D reconstruction of a novel ICP8-ssDNA complex, which seems to be the basic unit of the DNA annealing machine. The reconstructed volume consists of two nonameric rings containing ssDNA stacked on top of each other, corresponding to a molecular weight of 2.3 MDa. Fitting of the ICP8 crystal structure suggests a mechanism for the annealing reaction catalyzed by ICP8, which is most likely a general mechanism for protein-driven DNA annealing.
authors.affiliation: Lineberger Comprehensive Cancer Center, and Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. tolung.bio@gmail.com
authors.forename: Gökhan
authors.initials: G
authors.lastname: Tolun
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Makhov
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Ludtke
authors.forename: Jack D
authors.initials: JD
authors.lastname: Griffith
mesh_terms: D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry*; D008958:Models, Molecular; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C045462:ICP8 protein, Simplexvirus; D014764:Viral Proteins; D004247:DNA