Editing Post-translational modification (section)

== Structural changes ==
* [[disulfide bridge]]s, the covalent linkage of two [[cysteine]] amino acids
* [[lysine-cysteine bridge]]s, the covalent linkage of 1 lysine and 1 or 2 cystine residues via an oxygen atom (NOS and SONOS bridges)<ref>{{cite journal |last1=Rabe von Pappenheim |first1=Fabian |last2=Wensien |first2=Marie |last3=Ye |first3=Jin |last4=Uranga |first4=Jon |last5=Irisarri |first5=Iker |last6=de Vries |first6=Jan |last7=Funk |first7=Lisa-Marie |last8=Mata |first8=Ricardo A. |last9=Tittmann |first9=Kai |title=Widespread occurrence of covalent lysine–cysteine redox switches in proteins |journal=Nature Chemical Biology |date=April 2022 |volume=18 |issue=4 |pages=368–375 |doi=10.1038/s41589-021-00966-5 |doi-access=free|pmid=35165445 |pmc=8964421 }}</ref>
* [[proteolytic cleavage]], cleavage of a protein at a peptide bond
* [[isoaspartate]] formation, via the cyclisation of asparagine or aspartic acid amino-acid residues
* [[racemization]]
** of [[serine]] by [[protein-serine epimerase]]
** of [[alanine]] in [[dermorphin]], a frog [[opioid peptide]]
** of [[methionine]] in [[deltorphin]], also a frog opioid peptide
* [[protein splicing]], self-catalytic removal of [[intein]]s analogous to mRNA processing