Figure 4.

Sequence alignments of retroviral and Penelope-encoded proteins. (A) Sequence alignment of representative integrases of various retroelements with the putative integrase of Penelope. Amino acids identical or chemically similar to those of the putative Penelope protein are shown as gray boxes. Residues that form part of the Zn finger motif have been indicated by a + symbol, whereas amino acids in the DD35E motif are indicated by ∗. (B) Sequence alignment of RTs of various retroelements and the RT of Penelope. Dotted lines separate conserved blocks of RTs described by Xiong and Eickbush (21). Identical or chemically conserved residues are indicated as shaded boxes. Chemically similar amino acids are grouped as follows: A, S, T, P, and G; N, D, E, and Q; H, R, and K; M, L, I, and V; F, Y, and W (22).