Premium
Distal side tryptophan, tyrosine and methionine in catalase–peroxidases are covalently linked in solution
Author(s) -
Jakopitsch Christa,
Kolarich Daniel,
Petutschnig Gabriele,
Furtmüller Paul Georg,
Obinger Christian
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00901-3
Subject(s) - chemistry , tyrosine , adduct , tryptophan , catalase , covalent bond , peroxidase , stereochemistry , biochemistry , enzyme , amino acid , organic chemistry
Distal side tryptophan and tyrosine have been shown to be essential in the catalase but not the peroxidase activity of bifunctional catalase–peroxidases (KatGs). Recently published crystal structures suggest that both residues could be part of a novel adduct including in addition a conserved methionine. A mass spectrometric analysis of the tryptic peptides from recombinant wild‐type Synechocystis KatG and the variants Trp122Phe, Tyr249Phe and Met275Ile confirms that this novel adduct really exists in solution and thus may be common to all KatGs. Exchange of either Trp122 or Tyr249 prevents cross‐linking, whereas exchange of Met275 still allowed bond formation between Trp122 and Tyr249. It is proposed that the covalent bond between Trp and Tyr may form before that between Tyr and Met. The findings are discussed with respect to the mechanism of cross‐linking and its role in KatG catalysis.