Effect of R46 mutations in gp41 NHR region on viral infectivity and Env expression.

<p>(<b>A</b>) Infectivity of HIV-1 pseudoviruses carrying wild-type N36 and its mutants. Luciferase assay was used to measure the single-cycle infection of pseudovirus on TZM-bl cells. (<b>B</b>) Expression of gp120 and gp160 on pseudoviruses bearing wild-type N36 sequence and its mutants as determined by Western blot.</p

Using the MOE program to predict hydrogen bonds and salt bridges in 6-HB formed by C34 and N36, or N36’s mutants, or by N36 and C34, or C34’s mutants.

*<p>“0” indicates the absence of hydrogen bond or salt bridge between the two corresponding residues.</p

Interaction of C34 with N36 and its mutants to form 6-HB, as determined by FN-PAGE.

<p>C34 was labeled with FAM (carboxyfluorescein, Molecular Probes, Eugene, OR), which could be viewed under UV light.</p

CD spectrographic analysis of the complexes formed between N36 and C34 or their mutants.

<p>(<b>A</b>) The secondary structures of N36 and its mutants; (<b>B</b>) The secondary structures of the complexes formed by C34 and N36 or N36’s mutants; (<b>C</b>) The secondary structures of the complexes formed by N36 and C34 or C34’s mutants; and (<b>D</b>) The stability of complexes formed by C34 with N36 and its mutants, as measured by thermal denaturation analysis.</p

Inhibition of the peptides N36, C34 and their mutants on HIV-1_IIIB-mediated cell-cell fusion and HIV-1_IIIB infection.

*<p>Compared with the corresponding wild-type peptide N36 or C34 (Student <i>t</i>-test was performed using Excel).</p

Analysis of putative interactions of R46 in the gp41 NHR with the residues in the 6-HB formed between C34 and N36 or their mutants.

<p>(<b>A</b>) The 6-HB formed between C34 and N36; (<b>B</b>) The 6-HB formed between C34 and N36 R46A; (<b>C</b>) The 6-HB formed between C34 and R46E; (<b>D</b>) The 6-HB formed between C34 E137A and N36; and (<b>E</b>) The 6-HB formed between C34 E137R and N36. The putative interactions via hydrogen bond or salt bridge were predicted by using the MOE program. NHRs are colored in blue; CHR is colored in green.</p