The primary structure of the psychrophilic lactate dehydrogenase from Bacillus psychrosaccharolyticus.
L-lactate dehydrogenase of the psychrophilic bacterium B. psychrosaccharolyticus was isolated by a three-step procedure and its total amino-acid sequence determined by automated Edman degradation. The protein consists of 318 amino-acid residues and its calculated molecular mass is 35,254 Da. Most of the primary structure could be established by sequencing large peptide fragments obtained by chemical cleavages, namely with BNPS-skatole and with CNBr. Further fragmentations of two tryptophan peptides with the endoproteinase Lys-C and with diluted HCl resulted in shorter overlapping peptides, the analysis of which completed the sequence. The C-terminal sequence Glu-Gln was established by carboxypeptidase A experiments and was then verified by the analysis of short C-terminal tryptic and chymotryptic peptides. The first lactate dehydrogenase sequenced so far of a psychrophilic bacillus shows sequence homologies between 60% and 75% to the enzymes from the mesophilic B. megaterium and B. subtilis and the thermophilic B. stearothermophilus, B. caldolyticus and B. caldotenax. Within the 50 N-terminal residues, three additional sequences could be included in our comparisons. In this part of the molecule, sequence homologies between 56% and 74% were calculated.
Schlatter
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Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule, Zürich, Schweiz.
Kriech
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O
Suter
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Zuber
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H
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001407:Bacillus / Q000201:enzymology*; D003545:Cysteine / Q000032:analysis; D006868:Hydrolysis; D007770:L-Lactate Dehydrogenase / Q000032:analysis* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis
D000596:Amino Acids; D010446:Peptide Fragments; D007770:L-Lactate Dehydrogenase; D003545:Cysteine