Establishment of chronic hepatitis C virus infection: Translational evasion of oxidative defence

Figure 5 Delivery of ^MettRNA_i to the ribosome. Eukaryotic translation factor (eIF)2α forms a ternary complex with guanosine triphosphate (GTP) and the tRNA for the first methionine (^MettRNA_i) to deliver ^MettRNA_i to the 40S ribosomal subunit. Following hydrolysis of GTP to guanosine diphosphate (GDP), the eIF2α-GDP complex leaves the ribosome. GDP is converted to GTP in an exchange reaction catalyzed by the exchanger eIF2B. eIF2α-GTP can then be recycled for more ternary complex formation with ^MettRNA_i to continue translation initiation. When eIF2α is phosphorylated at Serine-51 (red), it inhibits eIF2B. Thus GDP cannot be exchanged for GTP and protein synthesis is arrested at this step.