Thioether protein crosslinks
Thioether bonds between the sidechains of cysteine and tyrosine have been well studied in cysteine dioxygenases[1], and observed in catalase[2] and galactose oxidase (see examples below).
Thioether bonds between cysteine and ligands are common, but are generally not crosslinks between polypeptides. Thioether bonds between cysteine and the vinyl groups of hemes are common. Diverse other ligands are bonded to protein via cysteine thioether linkages.
Note that the sidechain of methionine contains a thioether (which is not a protein crosslink).
An accurate estimate of the frequency of thioether crosslinks in the PDB may not be available. A search for "thioether" in Proteopedia yields >200 hits in abstracts of pages titled with 4-character PDB codes.
ExamplesExamples
Cys-TyrCys-Tyr
Cys-LigandCys-Ligand
- 5nf0 (2017): Peptide cyclized via 2 thioethers with xylene.
- 6o83 (2019): Ubiquitin-activating enzyme E1 thioether-bonded to a modified deoxy adenosine.
- 6vdq (2021): Bacterial peroxygenase thioether-bonded to heme.
Other Protein CrosslinksOther Protein Crosslinks
In addition to the thioester bonds discussed above, other covalent cross-links between polypeptide chains include:
- Disulfide bonds
- Isopeptide bonds
- Thioester protein crosslinks
- Ester protein crosslinks
- Histidine-tyrosine protein crosslinks
- Lysine-cysteine NOS bonds
ReferencesReferences
- ↑ Davies CG, Fellner M, Tchesnokov EP, Wilbanks SM, Jameson GN. The Cys-Tyr Crosslink of Cysteine Dioxygenase changes the Optimum pH of Reaction without Structural Change. Biochemistry. 2014 Nov 12. PMID:25390690 doi:http://dx.doi.org/10.1021/bi501277a
- ↑ Diaz A, Horjales E, Rudino-Pinera E, Arreola R, Hansberg W. Unusual Cys-Tyr covalent bond in a large catalase. J Mol Biol. 2004 Sep 17;342(3):971-85. PMID:15342250 doi:10.1016/j.jmb.2004.07.027