InterPro domain: IPR024909

Cysteine-tRNA ligase (also known as Cysteinyl-tRNA synthetase) ( 6.1.1.16 ) is an alpha monomer and belongs to class Ia [ 1 ]. It is highly specific despite not possessing the amino acid editing activity characteristic of many other tRNA ligases [ 2 ].

Mycothiol ligase, also known as L-cysteine:1D-myo-inositol 2-amino-2-deoxy-alpha-D-glucopyranoside ligase, uses ATP to ligate a Cys residue to a mycothiol precursor molecule, in the second to last step in mycothiol biosynthesis [ 3 ].

This entry represents a subgroup of the class-I aminoacyl-tRNA synthetase family. It includes cysteinyl-tRNA synthetase and the related enzyme mycothiol ligase [ 4 ].

1. Sequence determination and modeling of structural motifs for the smallest monomeric aminoacyl-tRNA synthetase. Proc. Natl. Acad. Sci. U.S.A. 88, 976-80
2. Structural origins of amino acid selection without editing by cysteinyl-tRNA synthetase. EMBO J. 21, 2778-87
3. A coupled spectrophotometric assay for l-cysteine:1-D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside ligase and its application for inhibitor screening. Anal. Biochem. 353, 167-73
4. ATP-dependent L-cysteine:1D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside ligase, mycothiol biosynthesis enzyme MshC, is related to class I cysteinyl-tRNA synthetases. Biochemistry 41, 6885-90