Cloning and characterization of the chloroplast elongation factor EF-Tu cDNA of Oryza sativa L.

From the rice leaf cDNA library, we have cloned a cDNA encoding rice chloro plast translational elongation factor EF-Tu (tufA). The rice tufA cDNA clon e contains 1678 nucleotides and codes for a 467 amino acid protein includin g a putative chloroplast transit peptide of 59 amino acid residues. The pre dicted molecular mass of the mature protein is approximately 45 kDa, This c DNA clone contains the 61 nucleotides of the 5' untranslated region (UTR) a nd the 213 nucleotides of 3' UTR, Amino acid sequence identity of the rice tufA with the mature chloroplast EF-Tu proteins of tobacco, pea, arabidopsi s, and soybean ranges from 83% to 86%. The deduced polypeptide of the rice tufA cDNA contains GTP binding domains in its N-terminal region and chlorop last EF-Tu signature regions in the C-terminal region, The rice tufA appear s to exist as a single copy gene, although its homologues of maize and oat exist as multiple copy genes. The rice tufA gent is located in chromosome 1 and is more highly expressed in the leaf than in root tissue.