Sequence analysis of the translational elongation factor 3 from Saccharomyces cerevisiae.

The gene YEF-3 encoding the elongation factor for protein synthesis in Saccharomyces cerevisiae is an essential gene as shown by one-step gene disruption and is located on chromosome XII as determined by orthogonal field alternation gel electrophoresis. The nucleotide sequence of the gene was determined from a sequential series of subclones generated from the YEF-3 gene cloned into bacteriophage M13. The HOMOL1 sequence and the RPG box, which are considered to be enhancer elements involved in coordinate regulation of transcription of the genes coding for yeast ribosomal proteins and protein synthesis factors, are found in the 5'-flanking region of the gene. A dyad symmetry that enables hairpin loop formation in the DNA molecule is found in the 3'-terminal at the termination site of transcription. An open reading frame of 3132 nucleotides codes for a deduced protein of 115,860 Da. A striking feature of the elongation factor 3 deduced polypeptide is the internal repeat of a region with approximately 200 amino acids which includes an ATP-binding site and shares similarity with some transport and drug-resistant proteins. Another characteristic is the presence of a highly charged C-terminal region composed of three basic polylysine blocks, suggesting interaction with RNA. The sequence supports the hypothesis that YEF-3 encodes a protein synthesis factor and suggests that its main role may be to transduce nucleoside triphosphate energy into mechanical energy for translocation during translation.