Arch Virol (2003) 148: 1225–1233
Identiﬁcation of the pocket factors in a picornavirus
, T. Pettitt
, A. Symonds
, and J. Martin
Molecular Structure Solutions, Wolverhampton, U.K.
Institute for Cancer Studies, University of Birmingham, Birmingham, U.K.
Division of Biomedical Sciences, School of Applied Sciences,
University of Wolverhampton, Wolverhampton, U.K.
Received September 4, 2002; accepted December 10, 2002
Published online April 9, 2003
Summary. Bovine enterovirus (BEV), along with other enteroviruses and the
rhinoviruses, has a hydrophobic pocket within structural protein VP1. In the
crystal structures of these viruses there is electron density commensurate with a
non-protein molecule within the pocket. These molecules, termed pocket factors,
have been shown to stabilise the capsid and their removal from the pocket is a
necessary prerequisite to uncoating. The pocket factors have been proposed, from
the electron densities and uncoating studies, to be short chain fatty acids. In order
to identify the pocket factor of BEV, we have grown and puriﬁed the virus in
an identical manner to that used for the crystal structure determination and have
performed a lipophilic extraction. Palmitic acid, C
, was the most abundant
accounting for 40.8% by mass of the lipophilic extract (39.3 mol%). Myristic acid
, was next most abundant at 18.5% by mass (20.0 mol%). In addition, we
have identiﬁed other fatty acids in smaller proportions. We have therefore shown
that BEV contains saturated fatty acid pocket factors of varying chain length. We
have also compared the proﬁle of the fatty acyl chain composition of BEV with
those for uninfected BHK-21 cell plasma membrane and endoplasmic reticulum
Picornaviruses are among the smallest animal viruses. The family Picornaviridae
is classiﬁed into nine genera: genus Enterovirus, which includes Bovine
(HRVs); genus Aphthovirus, which includes Foot-and-mouth disease virus
(FMDV); genus and the genera Cardiovirus, Erbovirus, Kobuvirus, Teschovirus,
Hepatovirus and Parechovirus.