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Shared motifs of the capsid proteins of hepadnaviruses and retroviruses suggest a common evolutionary origin
Author(s) -
Zlotnick Adam,
Stahl Steven J,
Wingfield Paul T,
Conway James F,
Cheng Naiqian,
Steven Alasdair C
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00755-8
Subject(s) - capsid , biology , protein subunit , virology , hepatitis b virus , virus , group specific antigen , helix bundle , protein structure , genetics , gene , biochemistry
The structure of the dimeric C‐terminal domain of the HIV‐1 capsid protein (CA), recently determined by X‐ray crystallography (Gamble et al. (1997)), has a notable resemblance to the structure of the hepatitis B virus (HBV) capsid protein (Cp) dimer, previously determined by cryo‐electron microscopy (Conway et al. (1997), Böttcher et al. (1997)). In both proteins, dimerization is effected by formation of a four‐helix bundle, whereby each subunit contributes a helix‐loop‐helix and most of the interaction between subunits is mediated by one pair of helices. These are the first two observations of a motif that is common to the capsid proteins of two enveloped viruses and quite distinct from the eight‐stranded anti‐parallel β‐barrel found in most other virus capsid proteins solved to date (Harrison et al. (1996)). Motivated by the structural resemblance, we have examined retroviral and HBV capsid protein sequences and found weak but significant similarities between them. These similarities further support an evolutionary relationship between these two virus families of great medical importance – the hepadnaviruses (e.g. HBV) and retroviruses (e.g. HIV).