Viruses structure and function

When a virus multiplies, the genome becomes released from the coat. This process occurs during the infection process. The present chapter is divided into three parts. The first part deals with basic concepts of virus structure and function. The second part deals with the nature and manner of multiplication of the bacterial viruses (bacteriophages). In this part we introduce the basic molecular biology of virus multiplication. The third part deals with important groups of animal viruses, with emphasis on molecular aspects of animal virus multiplication. 

Wiley, D.C., Skehel, JJ. The structure and function of the hemagglutinin membrane glycoprotein of influenza virus. Annu. Rev. Biochem. 56 365-394, 1987. 

Esposito D, Craigie R (1999) HIV integrase structure and function. Adv Virus Res 52 319-333 Evering TH, Markowitz M (2007) Raltegravir (MK-0518) an integrase inhibitor for the treatment of HlV-1. Drugs Today (Bare) 43 865-877... 

Currently, there is no approved antiviral therapy specifically targeting hepatitis C virus (HCV). The development of an HCV replicon system and our improved understanding of the structure and function of HCV proteins have led to the development of several classes of specific HCV inhibitors. NS3-4A protease inhibitors and NS5B polymerase inhibitors are furthest in development as discussed in Chaps. 2-4 (De and Migliaccio 2005 Manns et al. 2007 Pawlotsky et al. 2007). 

In one of the founding studies in immunotoxicology, Friend and Trainer [77] demonstrated that exposure to polychlorinated biphenyls (PCBs) increased mortality of mallard (Anas platyrhynchos) ducklings challenged with duck hepatitis virus. Since then the field of avian immunotoxicology has expanded to show that both the structure and function of the avian immune system often is affected by a diverse array of environmental contaminants, including heavy metals, pesticides, petroleum hydrocarbons, and organic industrial chemicals. Wild birds have proven to be excellent sentinel species for assess-... 

Structure and function of virus proteins and of viral nucleic acid. In The Proteins Composition, Structure, Function", Vol. 3, 99—151. Ed. II. Neurath, Academic Press, 2i,d Ed. 1965. 

Ruben S, Perkins A, Purcell R, et al. Structural and functional characterization of human immunodeficiency virus tat protein. J Virol 1989 63 1-8. 

Johnson, J., Lin, T., and Lomonosoff, G. (1997). Presentation of heterologous peptides on plant viruses genetics, structure and function. Anna. Reu Phytopathol. 35 67-86. 

Membranes play essential roies in the functions of both prokaryotic and eukaryotic cells. There is no unicellular or multicellular form of life that does not depend on one or more functional membranes. A number of viruses, the enveloped viruses, also have membranes. Cellular membranes are either known or suspected to be involved in numerous cellular functions, including the maintenance of permeability barriers, transmembrane potentials, active as well as specific passive transport across the membranes, hornione-receptor and transmitter-receptor responses, mitogenesis, and cell-cell recognition. The amount of descriptive material that might be included under the title of biological membranes is encyclopedic. The amount of material that relates or seeks to relate structure and function is less, but still large. For introductory references see Refs. 53, 38, 12, 47, 34, 13. Any survey of this field in the space and time available here is clearly out of the question. For the purposes of the present paper we have selected a rather narrow, specific topic, namely, the lateral diffusion of molecules in the plane of biological mem-branes.38,12,43,34 We consider this topic from the points of view of physical chemistry and immunochemistry. 

Development Based on Structures of Glycolytic Enzymes 16 Progress in the Design of Immunomodulators Based on the Structure of lnterleukin-1 17 Structure and Functional Studies of Interferon A Solid Foundation for Rational Drug Design 18 The Design of Anti-Influenza Virus Drugs from the X-ray Molecular Structure of Influenza Virus Ne... 

Viruses are somewhat unique in structure and function as compared with other microorganisms. The basic components of viral microorganisms are illustrated in Figure 34-1. A virus essentially consists of a core of viral DNA or RNA.18,62 The genetic core is surrounded by a protein shell, or capsid. This structure—the capsid enclosing the nucleic acid core—is referred to as the nucleocapsid. In some viruses, the nucleocapsid is also surrounded by a viral membrane, or envelope, which is composed of glycoproteins extending outward from a lipid bilayer. 

Heterologous expression systems have been of critical importance for the study of viral assembly at the molecular and structural levels. These systems afford enormous flexibility in terms of dissecting the assembly pathway and investigating protein—protein or protein—nucleic acid interactions in the absence of viral transcription and replication. In addition, moderate- to high-resolution structural analyses of assembly precursors, intermediates, and end products, all generated by expression in heterologous systems, have yielded unprecedented molecular details of the structure and function of virus particles. There can be no doubt that the application of heterologous expression systems will continue to provide answers to unresolved questions about viral assembly and structure. 

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