CLONING AND NUCLEOTIDE SEQUENCING OF THE GENES, RPLU AND RPMA, FOR RIBOSOMAL-PROTEINS L21 AND L27 OF ESCHERICHIA-COLI

The rplU and rpmA genes that encode ribosomal proteins (r-proteins) L2 1 and L27 of Escherichia coli K-12 have been isolated from the ordered clone bank of this bacterium. They were found to be located at coordi nates 3,351.7-3,352.3 kb on the physical map of E. coli. The nucleotid e sequence of the cloned genes and their flanking regions indicated th at the two r-protein genes compose an operon. Upstream of the two gene s there is an open reading frame (ORF) in the opposite direction. The deduced polypeptide encoded by this ORF has a molecular weight of 35,2 15 and shows a significant degree of sequence similarity to the eznyme that is involved in the carotenoid biosynthesis and encoded by the cr tE gene of carotenogenic bacteria and to prenyltransferases found in v arious organisms.