TY - JOUR
T1 - The structure of a neutralized virus
T2 - canine parvovirus complexed with neutralizing antibody fragment
AU - Wikoff, William R.
AU - Wang, Guoji
AU - Parrish, Colin R.
AU - Cheng, R. Holland
AU - Strassheim, M. Lisa
AU - Baker, Timothy S.
AU - Rossmann, Michael G.
PY - 1994
Y1 - 1994
N2 - Background Members of the Parvovirus genus cause a variety of diseases in mammals, including humans. One of the major defences against viral infection is the presence of neutralizing antibodies that prevent virus particles from infecting target cells. The mechanism of neutralization is not well understood. We therefore studied the structure of canine parvovirus (CPV) complexed with the Fab fragment of a neutralizing antibody, A3B10, using image reconstruction of electron micrographs of vitrified samples, together with the already known structure of CPV from X-ray crystallographic data. Results The structure of the complex of CPV with Fab A3B10 has been determined to 23 å resolution. The known CPV atomic structure was subtracted from the electron density of the complex, and the difference map was used to fit the atomic coordinates of a known Fab fragment, HyHEL-5. The long axis of each Fab molecule is oriented in a near radial direction, inclined away from the two-fold axes. The viral epitope consists of 14 amino acid residues found in loops 1, 2 and 3 on the capsid surface, which include previously identified escape mutations. Conclusions The mode of Fab binding suggests that the A3B10 neutralizing antibody cannot bind bivalently to the capsid across the two-fold axes, consistent with the observation that whole A3B10 antibody readily precipitates CPV. Since Fab A3B10 can also neutralize the virus, mechanisms of neutralization such as interference with cell attachment, cell entry, or uncoating, must be operative.
AB - Background Members of the Parvovirus genus cause a variety of diseases in mammals, including humans. One of the major defences against viral infection is the presence of neutralizing antibodies that prevent virus particles from infecting target cells. The mechanism of neutralization is not well understood. We therefore studied the structure of canine parvovirus (CPV) complexed with the Fab fragment of a neutralizing antibody, A3B10, using image reconstruction of electron micrographs of vitrified samples, together with the already known structure of CPV from X-ray crystallographic data. Results The structure of the complex of CPV with Fab A3B10 has been determined to 23 å resolution. The known CPV atomic structure was subtracted from the electron density of the complex, and the difference map was used to fit the atomic coordinates of a known Fab fragment, HyHEL-5. The long axis of each Fab molecule is oriented in a near radial direction, inclined away from the two-fold axes. The viral epitope consists of 14 amino acid residues found in loops 1, 2 and 3 on the capsid surface, which include previously identified escape mutations. Conclusions The mode of Fab binding suggests that the A3B10 neutralizing antibody cannot bind bivalently to the capsid across the two-fold axes, consistent with the observation that whole A3B10 antibody readily precipitates CPV. Since Fab A3B10 can also neutralize the virus, mechanisms of neutralization such as interference with cell attachment, cell entry, or uncoating, must be operative.
KW - antibody-virus complex
KW - antigenic surface
KW - cryo-electron microscopy
KW - neutralization of virus
KW - parvovirus
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U2 - 10.1016/S0969-2126(00)00062-9
DO - 10.1016/S0969-2126(00)00062-9
M3 - Article
C2 - 7522904
AN - SCOPUS:0028773903
VL - 2
SP - 595
EP - 607
JO - Structure with Folding & design
JF - Structure with Folding & design
SN - 0969-2126
IS - 7
ER -