N-terminal amino acid sequences of D-serine deaminases of wild-type and operator-constitutive strains of Escherichia coli K-12

DNA sequences of the D-serine deaminase control region and N-terminal portion of the structural gene

We determined the DNA sequence of the D-serine deaminase promoter region and of the N-terminal region of the structural gene. There are possibilities in the promoter for secondary structure and for initiation recognition sequences, and there is an open reading frame. The N-terminal sequence for the structural gene confirms that part of the amino acid sequence previously determined by E. Schlitz and W. Schmitt (FEBS Lett. 134:57-62, 1981), including the active site of the enzyme, and spans the two regions unresolved by their work.

Sequence studies on D-serine dehydratase of Escherichia coli. Primary structure of the tryptic phosphopyridoxyl peptide and of the N-terminus

An improved procedure for large-scale production of crystalline D-serine dehydratase (EC 4.2.1.14) from Escherichia coli is described. The N-terminal sequence of the enzyme (Mr 45500) was determined in a solid-phase sequencer as Met-Glu-Asn-Ala-Lys-Met-Asn-Ser-Leu-Ile-Ala-Gln-Tyr-Pro-Leu-Val-Lys-Asp-Leu-Val-Ala-LEU-Lys. Four of the first five N-terminal residues are homologeous with tryptophanase, another pyridoxal-phosphate (P-Pxy) enzyme that catalyzes alpha,beta-elimination reactions. After borohydride reduction and tryptic digestion of the enzyme, a peptide was isolated showing the sequence Lys-Asp-Ser-His-Leu-Pro-Ile-Ser-Gly-Ser-Ile-Lys(P-Pxy)-Ala-Arg. No clear homology of this portion of the enzyme with tryptophanase or another pyridoxal-phosphate enzyme was observed.