The
highlighted next-generation HIV-1 fusion inhibitor peptide <b>1</b> is capped by two threonines. Here, we generated peptide <b>2</b> by deleting the T–T motif and compared their structural and
antiviral properties. Significantly, two peptides showed similar helical
and oligomeric states in solution, comparable binding affinities to
the target, and no significant difference to inhibit HIV-1 fusion
and infection. Also, the T–T motif was not associated with
peptide <b>1</b> resistant mutations and its deletion did not
affect peptide <b>1</b> against enfuvirtide-resistant HIV-1
mutants. The redundancy of the T–T motif was further verified
by the model peptide C34 and short peptide inhibitors that mainly
target the gp41 pocket, suggesting that the N-terminal T–T
motif of peptide <b>1</b> could be removed or modified toward
the development of new anti-HIV-1 drugs. Consistently, our data have
verified that the M–T hook structure rather than the T–T
motif is an efficient strategy for short peptide fusion inhibitors