This family of proteins includes enzymes involved in the synthesis of cyclodipeptides using aminoacyl-tRNAs as substrates, including cyclo(L-leucyl-L-leucyl) synthase, cyclo(L-tyrosyl-L-tyrosyl) synthase and cyclo(L-leucyl-L-phenylalanyl) synthase. They are structurally similar to class Ic aminoacyl-tRNA synthetases (aaRSs) [1-3].

1: Structural basis for nonribosomal peptide synthesis by an aminoacyl-tRNA synthetase paralog. Bonnefond L, Arai T, Sakaguchi Y, Suzuki T, Ishitani R, Nureki O; Proc Natl Acad Sci U S A. 2011;108:3912-3917. PMID:21325056

2: The structure and mechanism of the Mycobacterium tuberculosis cyclodityrosine synthetase. Vetting MW, Hegde SS, Blanchard JS; Nat Chem Biol. 2010;6:797-799. PMID:20852636

3: Cyclodipeptide synthases, a family of class-I aminoacyl-tRNA synthetase-like enzymes involved in non-ribosomal peptide synthesis. Sauguet L, Moutiez M, Li Y, Belin P, Seguin J, Le Du MH, Thai R, Masson C, Fonvielle M, Pernodet JL, Charbonnier JB, Gondry M; Nucleic Acids Res. 2011;39:4475-4489. PMID:21296757