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Atomic insight into the CD4 binding-induced conformational changes in HIV-1 gp120
Shang-Te D Hsu1, Alexandre M J J Bonvin
1Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
Proteins
|April 23, 2004
Summary
Understanding HIV-1 entry dynamics is crucial. Molecular simulations reveal how CD4 binding to gp120 triggers conformational changes, enabling coreceptor binding and viral entry.
Area of Science:
- Molecular biology
- Structural biology
- Virology
Background:
- HIV-1 entry into target cells depends on gp120-CD4 interaction and coreceptor binding.
- Conformational changes in gp120 upon CD4 binding are critical but not fully understood.
Purpose of the Study:
- To investigate the dynamic conformational changes of gp120 during CD4 binding using molecular dynamics simulations.
- To elucidate the molecular mechanisms underlying HIV-1 entry initiation.
Main Methods:
- Molecular dynamics simulations in explicit solvent.
- Utilized gp120/CD4/CD4i crystal structure and modeled V3/V4 loops.
- Analyzed protein dynamics and interaction modes.
Main Results:
- Identified three distinct CD4-gp120 interaction modes (electrostatic, hydrogen bond, van der Waals).
- Proposed a 'binding funnel' model for gp120-CD4 interaction.
- Observed distinct dynamics for free and CD4-bound gp120, representing ground and pre-fusogenic states.
- Concerted motions in gp120 lead to V3 loop/bridging sheet stabilization and coreceptor binding site formation.
Conclusions:
- The study provides novel insights into the dynamic molecular recognition mechanism of HIV-1 entry.
- Findings complement existing biochemical and structural data on gp120-CD4 interactions.
- The proposed model enhances understanding of HIV-1 pre-fusion dynamics.