FIGURE 1.

Structural elements of the HIV-1 RT p51 C terminus that contribute to accommodating the RNA/DNA hybrid. For simplicity, the model in a highlights only the connection subdomains of p66 and p51 (yellow), the p66 RNase H domain (orange), and the p51 thumb (green). A portion of the RNA/DNA hybrid from Lapkouski et al. (23) is indicated, with DNA represented in blue and RNA represented in red. The peptide scanning Phe-416–Pro-421 of the p51 connection, which is in close contact to both strands of the RNA/DNA hybrid, is depicted in magenta, and α-helix M′ is in cyan. Residues Tyr-427 of α-helix M′ and Asn-348 of β-strand 20′, shown from our recent work to be involved in hydrogen bonding, are depicted in black. In b, this structure has been rotated 90° counterclockwise, and the p66 connection has been deleted. Residues Phe-416–Pro-421 are again highlighted in magenta.