Sequence of the DNA-binding protein gene of a human subgroup B adenovirus (type 7). Comparisons with subgroup C (type 5) and subgroup A (type 12).
The adenovirus type 7 (Ad7) single-stranded DNA-binding protein (DBP) structural gene has been sequenced and located between 66.7 and 62.3 map units. This region codes for a protein that contains 517 amino acid residues with a calculated molecular mass of 58,240 daltons. We compared the Ad7 amino acid sequence with those reported for the Ad5 (Kruijer, W., van Schaik, F.M.A., and Sussenbach, J.S. (1981) Nucleic Acids Res. 9, 4439-4457) and Ad12 (Kruijer, W., van Schaik, F.M.A., Speijer, J.G., and Sussenbach, J.S. (1983) Virology 128, 140-153) DNA-binding proteins. A greater amount of amino acid sequence homology was found in the carboxyl-terminal DNA-binding domain of the molecule. This homology is 61% between Ad7 and Ad5 and 49% when Ad12 was included in the comparison. The NH2-terminal domain of DBP retained a 49% homology between Ad7 and Ad5 and a 23% homology for all three serotypes. The greatest difference between the Ad7 and Ad5 DBPs is the absence, in the Ad7 protein, of 12 amino acids located between the two functional domains in the Ad5 protein (amino acids 151-162). In addition, three regions of high amino acid conservation between Ad5, Ad7, and Ad12 consisting of 9 (178-186), 9 (322-330), and 12 (464-475) consecutive amino acids (numbers refer to Ad5) in the DNA-binding portion of the molecule were revealed. These three regions contain a centrally located basic amino acid (183, 326, and 470) as well as an aromatic amino acid residue (181, 324, and 469). Since basic and aromatic amino acids have been implicated in other single-stranded DNA-binding protein/DNA interactions (Anderson, R.A., Nakashima, V., and Coleman, J.E. (1975) Biochemistry 14,907-917; Kowalczykowski, S.C., Lonberg, N., Newport, J.W., and von Hippel, P.H. (1981). J. Mol. Biol. 145, 75-104), these three conserved regions may represent DBP/DNA contact points.