Enzymatic thiolation of E. coli sRNA.

Abstract

In whole soluble ribonucleic-acid(sRNA), the pyrimidine S acceptor which yields 4-thiouridylic acid is uracil and not cytosine. Incubation of a dialyzed cell-free extract from Escherichia coli with sRNA and S35-cystine leads to labeling of the thionucleotides of the sRNA. The enzymatic reaction requires adenosine triphosphate (ATP), MgCl2, and pyridoxal phosphate. The E. coli sRNA serves as a good S acceptor substrate, while E. coli ribosomal RNA, periodate-treated E. coli sRNA, yeast or rabbit liver sRNA, and polyuridylic acid are inactive.