The N-terminal cysteine of human asparagine synthetase is essential for glutamine-dependent activity.
Site-specific mutagenesis was used to replace the N-terminal cysteine in human asparagine synthetase by an alanine. The mutant enzyme was expressed in the yeast Saccharomyces cerevisiae, and the asparagine synthetase activity was analyzed in vitro. The mutation resulted in the loss of the glutamine-dependent asparagine synthetase activity, while the ammonia-dependent activity remained unaffected. These results confirm the existence of a glutamine amidotransfer domain with an N-terminal cysteine essential for the glutamine-dependent asparagine synthetase activity.
Van Heeke
G
G
Department of Chemistry, University of Nebraska, Lincoln 68588.
Schuster
S M
SM
D000409:Alanine; D000582:Amidophosphoribosyltransferase / Q000235:genetics; D000595:Amino Acid Sequence; D001217:Aspartate-Ammonia Ligase / Q000235:genetics* / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D003545:Cysteine; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D008025:Ligases / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D015345:Oligonucleotide Probes; D005973:Glutamine; D000582:Amidophosphoribosyltransferase; D008025:Ligases; D001217:Aspartate-Ammonia Ligase; D003545:Cysteine; D000409:Alanine