A continuous 7802 nucleotide sequence spanning the 94% of foot and mouth disease virus RNA between the 5'-proximal poly(C) tract and the 3'-terminal poly(A) was obtained from cloned cDNA, and the total size of the RNA genome was corrected to 8450 nucleotides. A long open reading frame was identified within this sequence starting about 1300 bases from the 5' end of the RNA genome and extending to a termination codon 92 bases from its polyadenylated 3' end. The protein sequence of 2332 amino acids deduced from this coding sequence was correlated with the 260 K FMDV polyprotein. Its processing sites and twelve mature viral proteins were inferred from protein data, available for some proteins, a predicted cleavage specificity of an FMDV encoded protease for Glu/Gly(Thr, Ser) linkages, and homologies to related proteins from poliovirus. In addition, a short unlinked reading frame of 92 codons has been identified by sequence homology to the polyprotein initiation signal and by in vitro translation studies.

A cDNA clone of Foot and Mouth Diseases Virus (FMDV), strain C1, has been sequenced. The limits of the structural genes were defined by comparison with the available protein data. We identified two potential translation initiation sites for the viral polyprotein separated by 84 nucleotides. We suggest that these two initiation sites could be used to express two proteins differing only at the N-terminal, P16 and P20a. This model is supported by the fact that antiserum against a bacterially synthesized polypeptide corresponding to the anterior region of the polyprotein precipitates specifically both P16 and P20a. Comparison of the C1 sequence with two other serotypes, O1K and A10 revealed variability in the major immunogenic structural protein, VP1, and also in two other capsid proteins, VP2 and VP3. P16/P20a, VP4, and the N-terminal part of the precursor of the nonstructural genes, P52, are rather conserved between the different FMDV strains.

The interactions of cholate, deoxycholate, glycocholate, and taurocholate with methyl--cyclodextrin and 2-hydroxypropyl--cyclodextrin were studied by means of isothermal titration calorimetry and molecular modeling. The binding constants, standard molar enthalpy, Gibbs free energy, and entropy changes were determined for the formation of bile salt/cyclodextrin inclusion complexes. We observed a 1:1 stoichiometry for all inclusion complexes and could demonstrate marked differences in binding affinity between the different bile salt and cyclodextrin molecules. The dihydroxy bile salt deoxycholate showed significantly higher affinity toward methyl--cyclodextrin (K ) 6276 ( 164 M -1 ) and 2-hydroxypropyl--cyclodextrin (K ) 4429 ( 34 M -1 ) compared to the trihydroxy bile salt cholate (K ) 2693 ( 25 M -1 and K ) 2510 ( 98 M -1 , respectively). The conjugation of cholate with glycine or taurine lowered its affinity markedly toward methyl--cyclodextrin (K ) 1958 ( 178 M -1 and K ) 2148 ( 33 M -1 , respectively). Our molecular modeling and docking data suggest that the most probable mode of binding would be by insertion of the bile salt A-ring into the rim of the cyclodextrin containing the secondary alcohol moieties. Our results show that bile salt binding to cyclodextrin is influenced both by the degree of bile salt hydroxylation and by bile salt conjugation.

Three closely related genes for the small genome-linked protein (VPg) of picornaviruses have been identified by sequence analysis as a tandem repeat in the genome of Foot and Mouth Disease Virus (FMDV), strain O1K. This unusual structure was also found in the genome of strain C1O, belonging to a different FMDV serotype. Predicted biochemical properties of the three VPg gene products are in excellent agreement with the data from protein analysis of a heterogeneous VPg population from a third FMDV serotype, strain A10 (1). Taken together, these data indicate that the VPgs from all three genes function equally well in vivo. This is the first report of a tandem repeat gene in a viral genome.

Double-stranded DNA copies of the single-stranded genomic RNA of foot and mouth disease virus have been cloned into the Escherichia coli plasmid pBR322. A restriction map of the viral genome was established and aligned with the biochemical map of foot and mouth disease virus. The coding sequence for structural protein VP1, the major antigen of the virus, was identified and inserted into a plasmid vector where the expression of this sequence is under control of the phage lambda PL promoter. In an appropriate host the synthesis of antigenic polypeptide can be demonstrated by radioimmunoassay.