Huang C F, Chuang N N
Department of Zoology, National Taiwan University and Institute of Zoology, Academia Sinica, Nankang 11529, Taipei, Taiwan.
Gene. 1998 Dec 11;224(1-2):117-22. doi: 10.1016/s0378-1119(98)00528-9.
A cDNA was isolated from the shrimp Penaeus japonicus by homology cloning. The shrimp hepatopancreas cDNA encodes a 187-residue polypeptide whose predicted amino acid sequence shares 85% homology with mammalian K-Ras 4B protein and demonstrates identity in the guanine nucleotide binding domains. Expression of the shrimp cDNA in Escherichia coli yielded a 21-kDa polypeptide with a positive reactivity towards the monoclonal antibodies against mammalian Ras. The GTP binding of the shrimp ras-encoded fusion protein was approximated to be 30000units/mg of protein, whereas the binding for GDP was 5000units/mg of protein. Fluorography analysis demonstrated that the prenylation of both shrimp Ras GDP and shrimp Ras GTP by protein geranylgeranyltransferase I of shrimp Penaeus japonicus exceeded the shrimp Ras nucleotide-free form by 10-fold, and fourfold, respectively; that is, the shrimp protein geranylgeranyltransferase I prefers to react with the shrimp ras-encoded p25 fusion protein in the GDP-bound form.
