SEQUENCE CHARACTERIZATION AND COMPARISON OF HUMAN ADENOVIRUS SUBGENUS-B AND SUBGENUS-E HEXONS

The hexon genes of human adenovirus (AV) types 3, 16 (both subgenus B), and 4 (subgenus E) were sequenced and the nucleotide and predicted amino acid sequences were compared. We observed a high degree of homology between the three serotypes and thus could confirm the close evolutionary relationship of subgenera B and E which was previously inferred after comparing other genome regions. Employing the three-dimensional model of the AV2 hexon, the structures of the three herons were predicted. The major differences between the herons of AV3/AV16 and AV3/AV4 were confined to the I-1 and I-2 surface loops. As expected from cross-reactions in neutralization, the herons of AV16 and AV4 were not only very homologous in the conserved regions but also in the loops I-1 and I-2. This indicates that the type-specific antigenic determinant is located in these regions of the hexon. Closer examination of the loop I-4 sequences, Including also serotypes of subgenera A, C, and F, revealed that this region is subgenus-specific. The finding that AV4 differs from AV3 and AV16 in loop 1(4) supports the placement of AV4 in a separate subgenus. (C) 1995 Academic Press, Inc.