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Leishmania major thialysine N ε ‐acetyltransferase: Identification of amino acid residues crucial for substrate binding
Author(s) -
Lüersen Kai
Publication year - 2005
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/j.febslet.2005.08.063
Subject(s) - acetyltransferases , acetyltransferase , biochemistry , histone acetyltransferases , amino acid , cysteine , biology , peptide sequence , sequence alignment , mutant , chemistry , enzyme , acetylation , gene
Thialysine N ε ‐acetyltransferases and spermidine/spermine N ‐acetyltransferases (SSAT) are closely related members of the GCN5‐related N ‐acetyltransferase superfamily. Accordingly, a putative orthologue from the human protozoan parasite Leishmania major exhibits an almost equal similarity to human SSAT and thialysine N ε ‐acetyltransferase. Characterisation of the recombinantly expressed L. major protein indicated that it represents a thialysine N ε ‐acetyltransferase, preferring thialysine ( S ‐aminoethyl‐ l ‐cysteine) and structurally related amino acids as acceptor molecules. The known thialysine N ε ‐acetyltransferases contain five conserved amino acid residues that are replaced in SSAT sequences. Kinetic analyses of the respective recombinant mutant proteins suggest that Ser 82 and Thr 83 of L. major thialysine N ε ‐acetyltransferase are key residues for acceptor binding. In addition, the conserved Leu 130 is tentatively involved in specific interaction with the sulphur‐containing side chain of thialysine. The presence of these three amino acid residues is suggested to be a means by which thialysine N ε ‐acetyltransferases can be distinguished from SSAT sequences.