TY - CHAP M1 - Book, Section TI - Antiviral Agents and Resistance A1 - Ryan, Kenneth J. Y1 - 2022 N1 - T2 - Sherris & Ryan's Medical Microbiology, 8th Edition AB - Viruses are composed of either DNA or RNA, a protein coat (capsid), and, in many, a lipid or lipoprotein envelope. The nucleic acid codes for enzymes involved in replication and for several structural proteins. Viruses use molecules (eg, amino acids, purines, pyrimidines) supplied by the cell and cellular structures (eg, ribosomes) for synthetic functions. Thus, one of the challenges in the development of antiviral agents is identification of the steps in viral replication that are unique to the virus and not used by the normal cell. Among the unique viral events are attachment, penetration, uncoating, RNA-directed DNA synthesis (reverse transcription) or RNA-directed RNA synthesis (RNA viruses), and assembly and release of the intact virion. Each of these steps may have complex elements with the potential for inhibition. For example, assembly of some virus particles requires a unique viral enzyme, protease, and this has led to the development of protease inhibitors (PIs). A general scheme for the points of action of antiviral agents is shown in Figure 8–1. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1185628715 ER -