Premium
Nucleotide sequence of the asd gene of Escherichia coli: absence of a typical attenuation signal.
Author(s) -
Haziza C.,
Stragier P.,
Patte J.C.
Publication year - 1982
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1982.tb01178.x
Subject(s) - biology , escherichia coli , nucleic acid sequence , genetics , gene , sequence (biology) , escherichia coli proteins , nucleotide , microbiology and biotechnology
The asd gene of escherichia coli encodes aspartic semialdehyde dehydrogenase, an enzyme involved in lysine, threonine, and methionine biosynthesis; its synthesis is controlled by a multivalent repression mechanism. It was cloned in plasmid pBR322 and its complete nucleotide sequence determined. The sequence predicts a polypeptide chain of 367 amino acids, in good agreement with results obtained for the purified protein (Biellmann et al., 1980a). Our data indicate a Cys residue instead of a His residue, which was proposed after covalent labeling of the active center of the enzyme; this is more in line with the catalytic site of glyceraldehyde‐3‐phosphate dehydrogenase, an enzyme which carries out a similar reaction. The nucleotide sequence that precedes the translational start does not display any of the characteristic features of an attenuation signal. Hence the expression of the asd gene is probably not controlled in the same way as other multivalently repressed operons such as ilva and thr.