D-Glyceraldehyde-3-Phosphate Dehydrogenase. Complete Amino-Acid Sequence of the Enzyme from Bacillus stearothermophilus

Abstract

1. The complete amino acid sequence of D‐glyceraldehyde‐3‐phosphate dehydrogenase from the moderate thermophile Bacillus stearothermophilus has been determined. 2. This has been achieved largely by the automated sequence analysis of large fragments derived by chemical cleavage with cyanogen bromide, BNPS‐skatole [the product of reaction between N‐bromosuccinimide and 2‐(nitrophenyl‐sulphenyl)‐3‐methylindole] and hydroxylamine and enzymic hydrolysis with trypsin at arginine residues. 3. The sequence is as follows: It has been numbered to maximise homology with the four complete sequences of this enzyme from other sources. Hence the N‐terminal residue is numbered 0 and two deletions and two insertions have been introduced. 4. The inability of the B. stearothermophilus apo‐enzyme to transfer an acyl moiety from Cys‐149 to Lys‐183 observed with muscle enzymes is explained by the replacement of lysine by arginine in the enzyme from the thermophilic organism. 5. The sequences of the S‐loop regions, which form the core of the tetrameric enzyme, are similar to each other in B. stearothermophilus and Thermus aquaticus and differ from the highly conserved S‐loops of three enzymes from mesophiles.