The nucleotide sequence of the serA gene of Escherichia coli and the amino acid sequence of the encoded protein, D-3-phosphoglycerate dehydrogenase

The nucleotide sequence of serA, the structural gene of Escherichia coli which codes for D-3-phosphoglycerate dehydrogenase, has been determined. The structural gene contains 1233 nucleotides which code for the 409 amino acids of the subunit of the tetrameric enzyme, as well as the initiator methionine, which is cleaved from the mature protein, and the termination codon. The majority of the primary structure of the enzyme has been confirmed by automated Edman degradation of peptide fragments produced by a variety of cleavage agents. Comparison of the amino acid sequence of phosphoglycerate dehydrogenase with other NAD-dependent oxidoreductases reveals less than 20% homology, although conservation of certain specific residues in the coenzyme binding domain appears to be evident.