TAILIEUCHUNG - Báo cáo khóa học: Comparison of native and recombinant chlorite dismutase from Ideonella dechloratans

A detailed comparison between native chlorite dismutase from Ideonella dechloratans, and the recombinant version of the protein produced inEscherichia coli, suggests the presence of a covalent modification in the native enzyme. Although the native and recombinant N- and C-terminal sequences are identical, the enzymes display different electrophoretic mobilities, and produce different peptide maps upon digestion with trypsin and separation of fragments using capillary electrophoresis. | Eur. J. Biochem. 271 3539-3546 2004 FEBS 2004 doi Comparison of native and recombinant chlorite dismutase from Ideonella dechloratans Helena Danielsson Thorell1 Natascha H. Beyer2 Niels H. H. Heegaard2 Marcus Ohman1 and Thomas Nilsson1 1 Department of Chemistry Karlstad University Sweden 2Department of Autoimmunology Statens Serum Institut Copenhagen Denmark A detailed comparison between native chlorite dismutase from Ideonella dechloratans and the recombinant version of the protein produced in Escherichia coli suggests the presence of a covalent modification in the native enzyme. Although the native and recombinant N- and C-terminal sequences are identical the enzymes display different electrophoretic mobilities and produce different peptide maps upon digestion with trypsin and separation of fragments using capillary electrophoresis. Comparison of MALDI mass spectra of tryptic peptides from the native and recombinant enzymes suggests two locations for modification in the native protein. Mass spectrometric analysis of isolated peptides from a tryptic digest of the native enzyme identifies a possible cross-linked dipeptide suggesting an intrachain cross-link in the parent protein. Spectrophotometric titration of the native enzyme in the denatured state reveals two titrating components absorbing at 295 nm suggesting the presence of about one tyrosine residue per subunit with an anomalously low pKa. The EPR spectrum for the recombinant enzyme is different from that of the native enzyme and contains a substantial contribution of a low-spin species with the characteristics of bis-histidine coordination. These results are discussed in terms of a covalent cross-link between a histidine and a tyrosine sidechain similar to those found in other heme enzymes operating under highly oxidizing conditions. Keywords chlorate chlorite dismutase recombinant chlorite dismutase post-translational modification. Chlorate- and perchlorate-respiring .

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