STRUCTURE AND EXPRESSION OF CYSX, THE 2ND GENE IN THE ESCHERICHIA-COLI K-12 CYSE LOCUS

Protein products of the cysE region at 81 min on the chromosome of Escherichia coli K-12 (1) were analyzed by the maxicell method. Two kinds of polypeptides of molecular weight 33 K and 16 K were the products. The open reading frame (ORF) of the 33 K polypeptide consisted of 273 amino acids (Mr=29,261). On the other hand, the 16 K ORF was overlapped by the opposite 33 K ORF and specified an extremely basic protein of 130 amino acids (Mr=15,233). The gene coding for the 16 K polypeptide was named cysX. The expression of cysE and cysX in vivo was confirmed further by constructions of the cysE'-'lacZ and cysX'-'lacZ hybrid genes. © 1990.