Amino acid sequence analysis of the glutamate synthase enzyme from Escherichia coli K-12.
The amino acid sequence for the two subunits of the glutamate synthase of Escherichia coli K-12 was compared to the protein sequences compiled in the National Biomedical Research Foundation databank. Similarities were detected between the small glutamate synthase subunit and three members of the flavin-containing pyridine nucleotide-disulphide oxidoreductase superfamily, and also with three members of a lactate dehydrogenase family. Two segments in this glutamate synthase subunit showed similarity to regions previously proposed as part of dinucleotide-binding sites in some members of these two families. Similarity can be extended if the predicted secondary structure is considered. Based on these data, residues 148-260 and 289-409 in the small GOGAT subunit are proposed as dinucleotide-binding regions. Comparison of the amino acid sequence of the large glutamate synthase subunit with the glutamine phosphoribosylamine:pyrophosphate phosphoribosyltransferases of B. subtilis and E. coli revealed a significant similarity between the amino termini of these three enzymes. In these last two amidotransferases, the glutamine-binding site has been located in their amino-terminal region. The comparison with a second group of glutamine amidotransferases did not show any significant global similarity with the large glutamate synthase subunit. However, this polypeptide contains a small segment that shares similarity with a 13-amino acid segment proposed as part of the glutamine-binding site in this second group of amidotransferases.
Gosset
G
G
Departamento de Biología Molecular, Centro de Investigación sobre Ingeniería Genética y Biotecnología, Universidad Nacional Autónoma de México.
Merino
E
E
Recillas
F
F
Oliver
G
G
Becerril
B
B
Bolivar
F
F
D015109:4-Hydroxybenzoate-3-Monooxygenase; D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D005970:Glutamate Synthase / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D007256:Information Systems; D008432:Mathematical Computing; D008969:Molecular Sequence Data; D010088:Oxidoreductases; D011487:Protein Conformation; D000637:Transaminases / Q000378:metabolism
D005973:Glutamine; D010088:Oxidoreductases; D015109:4-Hydroxybenzoate-3-Monooxygenase; D005970:Glutamate Synthase; D000637:Transaminases