Progress in FY2016 was in the following areas: (1) HIV-1 CAPSID ASSEMBLIES: We have obtained quantitative structural constraints for the dimer interface in tubular CA assemblies, using a variety of solid state NMR techniques (BroBaRR, REDOR, NCCN tensor correlation, etc.) Previous studies by crystallography, cryoEM, and solution NMR have resulted in disparate structural models for this critical region of intermolecular association. From our solid state NMR constraints, we have developed a detailed structural model for the dimer interface in the tubular assemblies. This represents the first demonstration that solid state NMR measurements can provide new atomic-level structural information to complement information from cryoEM and crystallography. A paper describing this work has been published recently in JACS. (2) VIRUS-LIKE PARTICLES: We have examined virus-like particles (VLPs) formed by an HIV-1 Gag polyprotein construct that includes part of the MA domain, all of the CA and NC domains, and the SP1 spacer peptide between CA and NC. The VLPs mimic the Gag lattice of immature HIV-1 virions. Solid state NMR data provide strong evidence for alpha-helix formation by a 26-residue segment that spans the CA-SP1 junction. Helix formation by this segment had been proposed to stabilize the immature lattice, making CA-SP1 cleavage a prerequisite for HIV-1 maturation. This work has been published recently in JACS.

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Support Year
8
Fiscal Year
2016
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Indirect Cost
Name
U.S. National Inst Diabetes/Digst/Kidney
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Gupta, Sebanti; Tycko, Robert (2018) Segmental isotopic labeling of HIV-1 capsid protein assemblies for solid state NMR. J Biomol NMR 70:103-114
Bayro, Marvin J; Ganser-Pornillos, Barbie K; Zadrozny, Kaneil K et al. (2016) Helical Conformation in the CA-SP1 Junction of the Immature HIV-1 Lattice Determined from Solid-State NMR of Virus-like Particles. J Am Chem Soc 138:12029-32
Bayro, Marvin J; Tycko, Robert (2016) Structure of the Dimerization Interface in the Mature HIV-1 Capsid Protein Lattice from Solid State NMR of Tubular Assemblies. J Am Chem Soc 138:8538-46
Lu, Jun-Xia; Bayro, Marvin J; Tycko, Robert (2016) Major Variations in HIV-1 Capsid Assembly Morphologies Involve Minor Variations in Molecular Structures of Structurally Ordered Protein Segments. J Biol Chem 291:13098-112
Bayro, Marvin J; Chen, Bo; Yau, Wai-Ming et al. (2014) Site-specific structural variations accompanying tubular assembly of the HIV-1 capsid protein. J Mol Biol 426:1109-27
Chen, Bo; Tycko, Robert (2011) Simulated self-assembly of the HIV-1 capsid: protein shape and native contacts are sufficient for two-dimensional lattice formation. Biophys J 100:3035-44
Lu, Jun-Xia; Sharpe, Simon; Ghirlando, Rodolfo et al. (2010) Oligomerization state and supramolecular structure of the HIV-1 Vpu protein transmembrane segment in phospholipid bilayers. Protein Sci :
Chen, Bo; Tycko, Robert (2010) Structural and dynamical characterization of tubular HIV-1 capsid protein assemblies by solid state nuclear magnetic resonance and electron microscopy. Protein Sci 19:716-30