FIG 14.

Arteriviral nsp2 PRF. (A) Schematic representation of the expression of nsp2 moieties (based on LDV; accession number U15146.1). (B) Fragment of the pp1ab alignment corresponding to the site of nsp2 PRF. Columns containing amino acids whose tRNAs are present in the ribosomal P and A sites prior to frameshifting are highlighted with orange triangles. (C) Nucleotide alignment corresponding to the protein alignment presented in panel B. The slippery sequence is shown in orange and the C-rich element in cyan. Deviations from the canonical motifs, i.e., RG_GUU_UUU (R = G or A) and CCCANCUCC, are highlighted in red. For each sequence, the genome coordinate of the first nucleotide in the alignment is specified. If the frameshift site allows complete A-site duplex repairing in the −1 or −2 frame, then the length of the corresponding hypothetical protein product is specified. Otherwise, it is marked with a dash. Alignment columns containing the first nucleotides of −1TF and −2TF are highlighted with pink and blue bars, respectively.