cDNA-derived amino acid sequence of the gamma subunit of GTPase from bovine rod outer segments

Abstract

The sequence of the 74 amino acids in the gamma subunit of GTPase from bovine rod outer segments has been deduced from the cDNA sequence. Enriched GTPase mRNA was used to prepare a cDNA library in the expression vector lambda gt11. Clones encoding the gamma subunit were identified by screening the library with anti-GTPase antibodies and by cell-free translation of hybrid-selected mRNA. The longest cDNA (448 base pairs) contained the amino acid coding region for the entire gamma subunit as well as 5' and 3' noncoding regions of 67 and 159 base pairs, respectively. The 3' noncoding region contained the sequence, A-A-U-A-A-A, the presumed recognition sequence for polyadenylylation, and a 14-unit long poly(A) tract. The amino acid sequence derived for the gamma-subunit is mostly in agreement with that previously determined by McConnell and co-workers [McConnell, D. G., Kohnken, R. E. & Smith, A. J. (1984) Fed. Proc. Fed. Am. Soc. Exp. Biol. 43, 1585] and the partial sequence deduced by Van Dop and co-workers from cDNA [Van Dop, C., Medynski, D., Sullivan, K., Wu, A. M., Fung, B. K.-K. & Bourne, H. R. (1984) Biochem. Biophys. Res. Commun. 124, 250-255].