Expasy logo


ENZYME entry: EC

Accepted Name
oxazoline synthase
Alternative Name(s)
cyanobactin cyclodehydratase
cyanobactin heterocyclase
Reaction catalysed
  • ATP + L-amino acyl-L-seryl-[protein] <=> (S,S)-2-(C-substituted-aminomethyl)-4-acyl-2-oxazoline-[protein] + ADP + H(+) + phosphate
  • ATP + L-amino acyl-L-threonyl-[protein] <=> (S,S)-2-(C-substituted-aminomethyl)-4-acyl-5-methyl-2-oxazoline-[protein] + ADP + H(+) + phosphate
  • ATP + L-amino acyl-L-cysteinyl-[protein] <=> (1S,4R)-2-(C-substituted-aminomethyl)-4-acyl-2-thiazoline-[protein] + ADP + H(+) + phosphate
  • Requires Mg(2+).
  • The enzyme, which participates in the biosynthesis of ribosomal peptide natural products (RiPPs), converts L-cysteine, L-serine and L-threonine residues to thiazoline, oxazoline, and methyloxazoline rings, respectively.
  • The enzyme requires two domains - a cyclodehydratase domain, known as a YcaO domain, and a substrate recognition domain (RRE domain) that controls the regiospecificity of the enzyme.
  • The RRE domain can either be fused to the YcaO domain or occur as a separate protein; however both domains are required for activity.
  • The enzyme can process multiple residues within the same substrate peptide, and all enzymes characterized so far follow a defined order, starting with the L-cysteine closest to the C-terminus.
  • The reaction involves phosphorylation of the preceding ribosomal peptide backbone amide bond, forming ADP and a phosphorylated intermediate, followed by release of the phosphate group.
  • In some cases the enzyme catalyzes a side reaction in which the phosphorylated intermediate reacts with ADP to form AMP and diphosphate.
PRIAM enzyme-specific profiles6.2.2.2
KEGG Ligand Database for Enzyme Nomenclature6.2.2.2
IUBMB Enzyme Nomenclature6.2.2.2
MEDLINEFind literature relating to
Rhea expert-curated reactions6.2.2.2

View entry in original ENZYME format
View entry in raw text format (no links)
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.2.2.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.2.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.-.-.-