69168-08-7Relevant articles and documents
Ergothioneine biosynthetic methyltransferase EgtD reveals the structural basis of aromatic amino acid betaine biosynthesis
Vit, Allegra,Misson, La?titia,Blankenfeldt, Wulf,Seebeck, Florian P.
, p. 119 - 125 (2015/03/03)
Ergothioneine is an N-α-trimethyl-2-thiohistidine derivative that occurs in human, plant, fungal, and bacterial cells. Biosynthesis of this redox-active betaine starts with trimethylation of the α-amino group of histidine. The three consecutive methyl transfers are catalyzed by the S-adenosylmethionine-dependent methyltransferase EgtD. Three crystal structures of this enzyme in the absence and in the presence of N-α-dimethylhistidineand S-adenosylhomocysteine implicate a preorganized array of hydrophilic interactions as the determinants for substrate specificity and apparent processivity. We identified two active site mutations that change the substrate specificity of EgtD 107-fold and transform the histidine-methyltransferase into a proficient tryptophan-methyltransferase. Finally, a genomic search for EgtD homologues in fungal genomes revealed tyrosine and tryptophan trimethylation activity as a frequent trait in ascomycetous and basidomycetous fungi.
Thermodynamic view of hydrophobic association of side chains of aromatic amino acids
Iyengar, R. R.,Bhattacharya, P. K.
, p. 445 - 451 (2007/10/02)
The hydrophobic association constants, K, for the side chains of phenylalanine, tyrosin and tryptophan betains have been evaluated employing the difference in the mode of self-association of the optically pure L-betains and their DL-mixtures and using the
