The hexon genes of adenoviruses of subgenus C: comparison of the variable regions.

We report on a 1402-base pair long DNA sequence, encoding for the variable region and parts of the flanking conserved regions of the human adenovirus type 1 (AV1) hexon, and a DNA sequence comprising 1396 base pairs, encoding for the corresponding regions of the human adenovirus type 6 (AV6) hexon. AV1 and AV6, together with AV2 and AV5, belong to subgenus C. Comparison of the predicted amino acid sequences of AV1 and AV6 with those of AV2 and AV5 revealed that the variable hexon region could be subdivided into highly variable, variable and conserved regions. Regions differing between AV2, AV5, AV1 and AV6 were the same as those which were registered as different when comparing AV40 and AV41 (subgenus F), suggesting that these areas of the hexon protein represent type-specific antigenic determinants. Alignment of the amino acid sequences to the known 3-dimensional structure of the AV2 hexon demonstrated that the major amino acid changes were located in the L1 and L2 loops that form the surface of the hexon. Comparison of sequencing data between the serotypes might elucidate questions concerning evolution within subgenus C.