Dihydrofolate reductase: the amino acid sequence of the enzyme from a methotrexate-resistant mutant of Escherichia coli

• Published in: Biochemistry (Easton) Vol. 17; no. 7; pp. 1328 - 1337
• Main Authors: Bennett, Carl D, Rodkey, John A, Sondey, John M, Hirschmann, Ralph
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04-04-1978
• Subjects: Amino Acid Sequence; Cyanogen Bromide; Drug Resistance, Microbial; Escherichia coli - enzymology; Methotrexate - pharmacology; Mutation; Peptide Fragments; Tetrahydrofolate Dehydrogenase
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00600a030

The determination of the amino acid sequence of the enzyme dihydrofolate reductase (5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3) from a mutant of Escherichia coli B is described. The 159 residues were positioned by automatic Edman degradation of the whole protein, of the reduced and alkylated cyanogen bromide fragments, and of selected tryptic, chymotryptic, and thermolytic digestion products. An N-bromosuccinimide produced fragment of the largest cyanogen bromide peptide was also used in the sequence determination.