Zonglin Qiu1, Huihui Chong, Xue Yao, Yang Su, Sheng Cui, Yuxian He. 1. MOH Key Laboratory of Systems Biology of Pathogens and AIDS Research Center, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China. *Both Sheng Cui and Yuxian He contributed equally to this work.
Abstract
OBJECTIVE: Crystallographic studies of HIV-1 gp41 demonstrate a stable six-helix bundle (6-HB) folded by trimeric N and C-terminal heptad repeats (NHR and CHR), and a deep hydrophobic pocket (pocket-1) on the NHR helices (N-trimer); however, previous crystal structures of 6-HB core were determined by peptide fragments missing the downstream sequence of pocket-1; thus, the structural features of this site could not be observed. DESIGN: We recently determined several 6-HB structures containing the pocket-1 and its downstream site. Here, we focused to investigate the structural features of N-trimer previously uncharacterized. METHODS: Biophysical, biochemical and functional approaches were combined to characterize the downstream residues of pocket-1. RESULTS: A subpocket (designated pocket-2) was visualized on the C-terminal portion of N-trimer, which is formed by a cluster of seven residues, including Leu587, Lys588 and Glu584 on one NHR helix and Tyr586, Val583, Ala582 and Arg579 of another NHR helix. Mutagenesis studies demonstrated that the pocket-2 residues play essential roles for HIV-1 Env-mediated cell entry and critically determine the antiviral activity of NHR-derived peptide fusion inhibitor T21. Further, the pocket-2 mutations dramatically impaired the thermostability and conformation of 6-HB structure and reduced the binding affinity of CHR-derived inhibitor HP23 that specifically targets the deep pocket-1. CONCLUSION: These data have provided important information for the structure-function relationship of HIV-1 gp41 and for the development of antiviral entry inhibitors.
OBJECTIVE: Crystallographic studies of HIV-1 gp41 demonstrate a stable six-helix bundle (6-HB) folded by trimeric N and C-terminal heptad repeats (NHR and CHR), and a deep hydrophobic pocket (pocket-1) on the NHR helices (N-trimer); however, previous crystal structures of 6-HB core were determined by peptide fragments missing the downstream sequence of pocket-1; thus, the structural features of this site could not be observed. DESIGN: We recently determined several 6-HB structures containing the pocket-1 and its downstream site. Here, we focused to investigate the structural features of N-trimer previously uncharacterized. METHODS: Biophysical, biochemical and functional approaches were combined to characterize the downstream residues of pocket-1. RESULTS: A subpocket (designated pocket-2) was visualized on the C-terminal portion of N-trimer, which is formed by a cluster of seven residues, including Leu587, Lys588 and Glu584 on one NHR helix and Tyr586, Val583, Ala582 and Arg579 of another NHR helix. Mutagenesis studies demonstrated that the pocket-2 residues play essential roles for HIV-1Env-mediated cell entry and critically determine the antiviral activity of NHR-derived peptide fusion inhibitor T21. Further, the pocket-2 mutations dramatically impaired the thermostability and conformation of 6-HB structure and reduced the binding affinity of CHR-derived inhibitor HP23 that specifically targets the deep pocket-1. CONCLUSION: These data have provided important information for the structure-function relationship of HIV-1 gp41 and for the development of antiviral entry inhibitors.
Authors: S Stenler; K E Lundin; L Hansen; S Petkov; N Mozafari; M Isaguliants; P Blomberg; C I E Smith; D M Goldenberg; C-H Chang; K Ljungberg; J Hinkula; B Wahren Journal: Hum Vaccin Immunother Date: 2017-07-11 Impact factor: 3.452