Electrostatically constrained alpha-helical peptide inhibits replication of HIV-1 resistant to enfuvirtide.
Alpha-helical peptides, such as T-20 (enfuvirtide) and C34, derived from the gp41 carboxyl-terminal heptad repeat (C-HR) of HIV-1, inhibit membrane fusion of HIV-1 and the target cells. Although T-20 effectively suppresses the replication of multi-drug resistant HIV variants both in vitro and in vivo, prolonged therapy with T-20 induces emergence of T-20 resistant variants. In order to suppress the emergence of such resistant variants, we introduced charged and hydrophilic amino acids, glutamic acid (E) and lysine (K), at the solvent accessible site of C34. In particular, the modified peptide, SC34EK, demonstrates remarkably potent inhibition of membrane fusion by the resistant HIV-1 variants as well as wild-type viruses. The activity was specific to HIV-1 and little influenced by serum components. We found a strong correlation between the anti-HIV-1 activities of these peptides and the thermostabilities of the 6-helix bundles that are formed with these peptides. We also obtained the crystal structure of SC34EK in complex with a 36 amino acid sequence (N36) comprising the amino-terminal heptad repeat of HIV-1. The EK substitutions in the sequence of SC34EK were directed toward the solvent and generated an electrostatic potential, which may result in enhanced alpha-helicity of the peptide inhibitor. The 6-helix bundle complex of SC34EK with N36 appears to be structurally similar to that of C34 and N36. Our approach to enhancing alpha-helicity of the peptide inhibitor may enable future design of highly effective and specific HIV-1 inhibitors.
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Hiroki
H
Nishikawa
Shota
S
Nakamura
Eiichi
E
Kodama
Saori
S
Ito
Keiko
K
Kajiwara
Kazuki
K
Izumi
Yasuko
Y
Sakagami
Shinya
S
Oishi
Tadayasu
T
Ohkubo
Yuji
Y
Kobayashi
Akira
A
Otaka
Nobutaka
N
Fujii
Masao
M
Matsuoka
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D015195:Drug Design; D024882:Drug Resistance, Viral; D000077560:Enfuvirtide; D015700:HIV Envelope Protein gp41 / Q000494:pharmacology*; D023581:HIV Fusion Inhibitors / Q000494:pharmacology*; D015497:HIV-1 / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D055672:Static Electricity; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects*
D015700:HIV Envelope Protein gp41; D023581:HIV Fusion Inhibitors; D010446:Peptide Fragments; D010455:Peptides; D000077560:Enfuvirtide