Solid-State NMR Studies of HIV-1 Capsid Protein Assemblies

摘要

Abstract: In mature HIV-1 virions, the 26.6 kDa CA protein is assembled into a characteristic cone-shapedncore (capsid) that encloses the RNA viral genome. The assembled capsid structure is best described byna fullerene cone model that is made up from a hexameric lattice containing a variable number of CAnpentamers, thus allowing for closure of tubular or conical structures. In this paper, we present a solid-statenNMR analysis of the wild-type HIV-1 CA protein, prepared as conical and spherical assemblies that arenstable and are not affected by magic angle spinning of the samples at frequencies between 10 and 25nkHz. Multidimensional homo- and heteronuclear correlation spectra of CA assemblies of uniformly 13C,n15N-nlabeled CA exhibit narrow lines, indicative of the conformational homogeneity of the protein in thesenassemblies. For the conical assemblies, partial residue-specific resonance assignments were obtained.nAnalysis of the NMR spectra recorded for the conical and spherical assemblies indicates that the CA proteinnstructure is not significantly different in the different morphologies. The present results demonstrate thatnthe assemblies of CA protein are amenable to detailed structural analysis by solid-state NMR spectroscopy.