title: The amino-acid sequence of the dihydrofolate reductase of a trimethoprim-resistant strain of Escherichia coli.
abstract: The determination of the amino acid sequence of the dihydrofolate reductase from Escherichia coli RT500 is described. The sequence, comprising 159 residues, has been derived from automatic sequencing of the intact protein in conjunction with manual sequencing of lysine-blocked tryptic peptides, Staphylococcus aureus protease peptides, and alpha-lytic protease peptides. Comparison of the sequence with that of the dihydrofolate reductase from a methotrexate-resistant strain of E. coli (MB1428) shows that 145 of the residues are identical. The distribution of the differences along the length of the molecule is discussed.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D003488:Cyanogen Bromide; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D010446:Peptide Fragments / Q000032:analysis; D010447:Peptide Hydrolases; D013211:Staphylococcus aureus / Q000201:enzymology; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D014295:Trimethoprim / Q000494:pharmacology*; D014357:Trypsin
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D014295:Trimethoprim; D013762:Tetrahydrofolate Dehydrogenase; D010447:Peptide Hydrolases; D014357:Trypsin; D003488:Cyanogen Bromide