6UI6

HBV T=3 149C3A

Summary for 6UI6

• Entry DOI: 10.2210/pdb6ui6/pdb
• EMDB information: 20669 20670
• Descriptor: Core protein (1 entity in total)
• Functional Keywords: hbv, virus
• Biological source: Hepatitis B virus (HBV)
• Total number of polymer chains: 3
• Total formula weight: 48430.16

Authors

Wu, W.,Watts, N.R.,Cheng, N.,Huang, R.,Steven, A.,Wingfield, P.T. (deposition date: 2019-09-30, release date: 2019-11-06, Last modification date: 2024-03-13)

Primary citation

Wu, W.,Watts, N.R.,Cheng, N.,Huang, R.,Steven, A.C.,Wingfield, P.T.
Expression of quasi-equivalence and capsid dimorphism in the Hepadnaviridae.
Plos Comput.Biol., 16:e1007782-e1007782, 2020

PubMed Abstract: Hepatitis B virus (HBV) is a leading cause of liver disease. The capsid is an essential component of the virion and it is therefore of interest how it assembles and disassembles. The capsid protein is unusual both for its rare fold and that it polymerizes according to two different icosahedral symmetries, causing the polypeptide chain to exist in seven quasi-equivalent environments: A, B, and C in AB and CC dimers in T = 3 capsids, and A, B, C, and D in AB and CD dimers in T = 4 capsids. We have compared the two capsids by cryo-EM at 3.5 Å resolution. To ensure a valid comparison, the two capsids were prepared and imaged under identical conditions. We find that the chains have different conformations and potential energies, with the T = 3 C chain having the lowest. Three of the four quasi-equivalent dimers are asymmetric with respect to conformation and potential energy; however, the T = 3 CC dimer is symmetrical and has the lowest potential energy although its intra-dimer interface has the least free energy of formation. Of all the inter-dimer interfaces, the CB interface has the least area and free energy, in both capsids. From the calculated energies of higher-order groupings of dimers discernible in the lattices we predict early assembly intermediates, and indeed we observe such structures by negative stain EM of in vitro assembly reactions. By sequence analysis and computational alanine scanning we identify key residues and motifs involved in capsid assembly. Our results explain several previously reported observations on capsid assembly, disassembly, and dimorphism.

PubMed: 32310951
DOI: 10.1371/journal.pcbi.1007782

Experimental method

ELECTRON MICROSCOPY (3.53 Å)