Methionine--tRNA ligase, cytoplasmic (MARS1) is a 900-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P56192.
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The mean pLDDT of this model is 90.3 (very high overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 73% |
| 70 to 90 | Confident: backbone generally right | 21% |
| 50 to 70 | Low: treat with caution | 1% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Catalyzes the specific attachment of L-methionine to its cognate tRNA in a 2 step reaction: the amino acid (AA) is first activated by ATP to form AA-AMP and then transferred to the acceptor end of the tRNA (PubMed:11714285, PubMed:33909043). Plays a role in the synthesis of ribosomal RNA in the nucleolus (PubMed:10791971). In addition, can prevent the misincorporation of homocysteine into tRNA and protein by catalyzing a tRNA-independent hydrolysis of the misactivated homocysteinyl-AMP intermediate. The homocysteinyl-AMP intermediate undergoes an intramolecular cyclization reaction in which the thiolate side chain of homocysteine displaces the AMP group, forming homocysteine-thiolactone…
Monomer (PubMed:11714285). Part of a multisubunit complex that groups tRNA ligases for Arg (RARS1), Asp (DARS1), Gln (QARS1), Ile (IARS1), Leu (LARS1), Lys (KARS1), Met (MARS1) the bifunctional ligase for Glu and Pro (EPRS1) and the auxiliary subunits AIMP1/p43, AIMP2/p38 and EEF1E1/p18 (PubMed:19131329, PubMed:19289464, PubMed:26472928, Ref.26). Forms a linear complex that contains MARS1,…
Cytoplasm, cytosol, Nucleus, nucleolus
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 4BVX | X-ray | 1.6 Å | A=1-207 |
| 4BL7 | X-ray | 1.89 Å | A=1-224 |
| 4BVY | X-ray | 1.99 Å | A=1-225 |
| 5GL7 | X-ray | 2.01 Å | A=221-834 |
| 5GOY | X-ray | 2.28 Å | A=221-834 |
| 5Y6L | X-ray | 2.9 Å | A=1-224 |
| 2DJV | NMR | A=835-900 |
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