Primary structure of Escherichia coli ribosomal protein L31

Abstract

Protein L31 from the 50S ribosomal subunit of E. coli was manually sequenced by the dansyl-Edman method. Owing to the availability of only small quantities of purified L31, sequencing methods were scaled down such that the entire primary structure could be determined with 700 .mu.g of protein. The techniques employed are described in detail. The protein consists of a single chain of 62 amino acids, with a calculated MW of 6967. Four half-cystine residues were identified at positions 16, 18, 37 and 40. These residues probably form 2 disulfide bridges in the protein, as isolated.