Genome packaging is a key step in morphogenesis of large double-stranded DNA (dsDNA) viruses including tailed double-stranded DNA bacteriophages and herpesviruses, and is essential for assembly of infectious progeny virions. Genome packaging is a precisely coordinated molecular synergy, in which a certain amount of viral DNA from a DNA concatemer is inserted into a preformed procapsid, followed by binding of additional viral proteins to the capsid to retain the packaged DNA. This DNA insertion process is fulfilled by a powerful molecular machine consisting of the terminase and the portal. The portal forms a conduit at a single vertex of the capsid that allows viral DNA to enter during virus assembly and exit during infection. The terminase complex contains a DNA-recognition subunit that specifically binds to the viral DNA, and a catalytic subunit that provides the energy for the packaging reaction and cleaves the genome-length DNA from the concatemer. Molecular mechanisms of genome packaging in these large viruses are not well understood, owing to unusual complexity and lack of high resolution structural data. In particular, these genome-packaging proteins have to form high-order molecular assemblies in order to function. The portal protein forms a ring-like dodecamer embedded in the capsid. However, little is known about how the terminase assembles, how it assembles with the portal, and how the portal is embedded in the capsid. Our goal is to understand molecular mechanisms of genome packaging in DNA viruses by analyzing assemblies of genome-packaging proteins using structural approaches. We are particularly interested in the general question of how numerous proteins and other biological molecules, each present in multiple copies, assemble hierarchically into a sophisticated system to fulfill a complex biological process. In the present proposal, we seek to: (i) elucidate the high resolution structure of a complete, infectious bacterial virus;(ii) elucidate structures of component proteins of the terminase;(iii) elucidate the mode of DNA-binding for a terminase DNA-recognition protein;and (iv) explore the assembly of the terminase complex in vitro. Herpes viruses are important human pathogens that cause diseases ranging from chickenpox to various forms of cancer. This proposal is anticipated to contribute to public health by identification of novel targets of antiviral to control and prevent infection and diseases caused by herpes viruses.
Human herpesviruses are linked to important human diseases ranging from chickenpox to life-threatening cancer. The majority of individuals in most human populations are infected by several herpesviruses. We seek to investigate a common molecular mechanism in life cycles of herpesvirus and many other large double- stranded DNA viruses, in search of new measures to control and prevent infection and diseases caused by these viral pathogens.
|Masaoka, Takashi; Zhao, Haiyan; Hirsch, Danielle R et al. (2016) Characterization of the C-Terminal Nuclease Domain of Herpes Simplex Virus pUL15 as a Target of Nucleotidyltransferase Inhibitors. Biochemistry 55:809-19|
|Zhao, Haiyan; Speir, Jeffrey A; Matsui, Tsutomu et al. (2016) Structure of a Bacterial Virus DNA-Injection Protein Complex Reveals a Decameric Assembly with a Constricted Molecular Channel. PLoS One 11:e0149337|
|Yu, Guimei; Li, Kunpeng; Liu, Yue et al. (2016) An algorithm for estimation and correction of anisotropic magnification distortion of cryo-EM images without need of pre-calibration. J Struct Biol 195:207-15|
|Zhao, Haiyan; Lin, Zihan; Lynn, Anna Y et al. (2015) Two distinct modes of metal ion binding in the nuclease active site of a viral DNA-packaging terminase: insight into the two-metal-ion catalytic mechanism. Nucleic Acids Res 43:11003-16|
|Tewary, Sunil K; Liang, Lingfei; Lin, Zihan et al. (2015) Structures of minute virus of mice replication initiator protein N-terminal domain: Insights into DNA nicking and origin binding. Virology 476:61-71|
|Zhao, Haiyan; Christensen, Theodore E; Kamau, Yvonne N et al. (2013) Structures of the phage Sf6 large terminase provide new insights into DNA translocation and cleavage. Proc Natl Acad Sci U S A 110:8075-80|
|Tewary, Sunil Kumar; Zhao, Haiyan; Shen, Weiran et al. (2013) Structure of the NS1 protein N-terminal origin recognition/nickase domain from the emerging human bocavirus. J Virol 87:11487-93|
|Selvarajan Sigamani, Sundaresan; Zhao, Haiyan; Kamau, Yvonne N et al. (2013) The structure of the herpes simplex virus DNA-packaging terminase pUL15 nuclease domain suggests an evolutionary lineage among eukaryotic and prokaryotic viruses. J Virol 87:7140-8|
|Zhao, Haiyan; Kamau, Yvonne N; Christensen, Theodore E et al. (2012) Structural and functional studies of the phage Sf6 terminase small subunit reveal a DNA-spooling device facilitated by structural plasticity. J Mol Biol 423:413-26|
|Zhao, Haiyan; Sequeira, Reuben D; Galeva, Nadezhda A et al. (2011) The host outer membrane proteins OmpA and OmpC are associated with the Shigella phage Sf6 virion. Virology 409:319-27|