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An alternative mechanism for the nitrogen transfer reaction in asparagine synthetase
Author(s) -
Richards Nigel G.J.,
Schuster Sheldon M.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81421-h
Subject(s) - asparagine , glutamine , histidine , asparagine synthetase , glutamine synthetase , chemistry , escherichia coli , residue (chemistry) , biochemistry , mechanism (biology) , nitrogen , stereochemistry , amino acid , organic chemistry , philosophy , epistemology , gene
In the absence of crystallographic data, the mechanism of nitrogen transfer from glutamine in asparagine synthetase (AS) remains under active investigation. Surprisingly, the glutamine‐dependent AS from Escherichia coli (AsnB) appears to lack a conserved histidine residue, necessary for nitrogen transfer if the reaction proceeds by the accepted pathway in other glutamine amidotransferases, but retains ability to synthesize asparagine. We propose an alternative mechanism for nitrogen transfer in AsnB which obviates the requirement for participation of histidine in this step. Our hypothesis may also be more generally applicable to other glutamine‐dependent amidotransferases.