dehydroalanine (Cys) -33.987720489501953125 -34.0800018310546875 2,3-didehydroalanine 2-aminoacrylic acid 2-aminopropenoic acid 4-methylidene-imidazole-5-one (MIO) active site 69.02146148681640625 69.05999755859375 A protein modification that effectively converts an L-cysteine residue to dehydroalanine. C C 0 H -2 N 0 O 0 S -1 C 3 H 3 N 1 O 1 Cys->Dha Dehydroalanine (from Cysteine) Dehydroalanine (from Cysteine) Dha From DeltaMass: In an attempt to clarfiy the difference between the modification of cysteine to lanthionine and cysteine to dehydroalanine, the following contributions from the ABRF email forum are presented:Structurally speaking lanthionine is like cystine but lacks one S atom. I imagine one can think of it as a condensation of cysteine and dehydroalanine but I do not know how it is made biologically. Dehydroalanine could be derived from either serine or cysteine. If I recall Biochem 101 correctly lanthionine was first found in wool.-Lowell Ericsson (ERICSSONLH@U.WASHINGTON.EDU)As far as I know, the structure of lanthionine is two Ala's joined by a single sulphur with the loss of two hydrogens from the methyl group of the Ala.Stephen Bayne (sbay@novo.dk)Regarding the structure of lanthionine and dehydroalanine: dehydroalanine is formed by the loss of one sulfur atom and two hydrogen atoms from ONE cysteine residue. lanthionine is formed from TWO cysteines, is a thioether, and contains one sulfur atom less than the amino acid cystine. Dan McCormick (MCCORMICK@rcf.mayo.edu) [DeltaMass]. Most bacterially produced lanthionine crosslinks are made by dehydration of L-serine to dehydroalanine, and then reaction with L-cysteine so as to produce chiral inversion at the alpha-carbon of the original L-serine; the lanthionine is a meso-diastereomer with L-configuration of the original cysteine alpha-carbon and D-configuration of the original L-serine alpha-carbon. In cypemycin dehydroalanine has been shown to be produced by loss of hydrogen sulfide from cysteine. Beta-elimination of hydrogen sulfide does occur during treatment with performic acid [JSG]. MOD:00793 MOD_RES 2,3-didehydroalanine (Cys) PSI-MOD Unimod:368 anhydroserine dHAla(Cys) dehydroalanine natural uniprot.ptm:PTM-0468 modified L-cysteine residue dehydroalanine