Premium
Arabidopsis amidase 1, a member of the amidase signature family
Author(s) -
Neu Daniel,
Lehmann Thomas,
Elleuche Skander,
Pollmann Stephan
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05876.x
Subject(s) - amidase , biochemistry , catalytic triad , amidohydrolase , amino acid , biology , acetamide , active site , hydrolase , stereochemistry , enzyme , chemistry , astrobiology
Amidase 1 (AMI1), a specific indole‐3‐acetamide amidohydrolase, is an Arabidopsis thaliana amidase signature enzyme that catalyzes the synthesis of indole‐3‐acetic acid from indole‐3‐acetamide. Amidase signature family members catalyze a diverse range of enzymatic reactions and are found widespread in nature, for instance in bacteria, mammals, and plants. At the protein level, the family members share a conserved stretch of ≈ 50–130 amino acids, the name‐giving amidase signature. Elucidation of the crystal structures of a mammalian fatty acid amide hydrolase and the bacterial malonamidase E2 revealed an unusual Ser‐ cis Ser‐Lys catalytic triad in proteins of this family. In addition, other members, such as the amidase from Rhodococcus rhodochrous strain J1 or Sulfolobus solfataricus , seem to use an accessory Cys‐ cis Ser‐Lys center. AMI1 possesses all conserved amino‐acid residues of the Ser‐ cis Ser‐Lys triad, but lacks the CX 3 C motif and therefore the Cys‐ cis Ser‐Lys catalytic site. Using a set of point‐mutated variants of AMI1 and chemical modifications, we analyzed the relative importance of single amino‐acid residues of AMI1 with respect to substrate conversion. These experiments revealed that a specific serine residue, Ser137, is essential for AMI1 enzymatic activity. We also report structural and functional differences of AMI1 from other amidase signature enzymes.