Reconciling NMR Structures of the HIV-1 Nucleocapsid Protein NCp7 Using Extensive Polarizable Force Field Free-Energy Simulations

J Chem Theory Comput. 2020 Apr 14;16(4):2013-2020. doi: 10.1021/acs.jctc.9b01204. Epub 2020 Mar 30.

Abstract

Using polarizable (AMOEBA) and nonpolarizable (CHARMM) force fields, we compare the relative free energy stability of two extreme conformations of the HIV-1 nucleocapsid protein NCp7 that had been previously experimentally advocated to prevail in solution. Using accelerated sampling techniques, we show that they differ in stability by no more than 0.75-1.9 kcal/mol depending on the reference protein sequence. While the extended form appears to be the most probable structure, both forms should thus coexist in water explaining the differing NMR findings.

MeSH terms

  • Entropy
  • Magnetic Resonance Spectroscopy
  • Molecular Dynamics Simulation
  • gag Gene Products, Human Immunodeficiency Virus / chemistry*

Substances

  • NCP7 protein, Human immunodeficiency virus 1
  • gag Gene Products, Human Immunodeficiency Virus