tailieunhanh - Báo cáo khoa học: Isolation and characterization of a D-cysteine desulfhydrase protein from Arabidopsis thaliana

In several organisms d-cysteine desulfhydrase (d-CDes) activity (EC ) was measured; this enzyme decomposes d-cysteine into pyruvate, H2S, and NH3. A gene encoding a putative d-CDes protein was identified in Arabidopsis thaliana(L) Heynh. based on high homology to an Escherichia coliprotein called YedO that hasd-CDes activity. The deduced Arabidopsisprotein consists of 401 amino acids and has a molecular mass of kDa. | ềFEBS Journal Isolation and characterization of a D-cysteine desulfhydrase protein from Arabidopsis thaliana Anja Riemenschneider Rosalina Wegele Ahlert Schmidt and Jutta Papenbrock Institute for Botany University of Hannover Germany Keywords 1-aminocyclopropane-1-carboxylate deaminase Arabidopsis thaliana D-cysteine desulfhydrase YedO Correspondence J. Papenbrock Institute for Botany University of Hannover Herrenhauserstrasse 2 D-30419 Hannover Germany Fax 49 511762 3992 Tel 49 511762 3788 E-mail . Received 19 November 2004 revised 3 January 2005 accepted 11 January 2005 doi In several organisms D-cysteine desulfhydrase D-CDes activity EC was measured this enzyme decomposes D-cysteine into pyruvate H2S and NH3. A gene encoding a putative D-CDes protein was identified in Arabidopsis thaliana L Heynh. based on high homology to an Escherichia coli protein called YedO that has D-CDes activity. The deduced Arabidopsis protein consists of 401 amino acids and has a molecular mass of kDa. It contains a pyridoxal-5 -phosphate binding site. The purified recombinant mature protein had a Km for D-cysteine of mM. Only D-cysteine but not L-cysteine was converted by D-CDes to pyruvate H2S and NH3. The activity was inhibited by aminooxy acetic acid and hydroxylamine inhibitors specific for pyridoxal-5 -phosphate dependent proteins at low micromolar concentrations. The protein did not exhibit 1-aminocyclopro-pane-1-carboxylate deaminase activity EC as homologous bacterial proteins. Western blot analysis of isolated organelles and localization studies using fusion constructs with the green fluorescent protein indicated an intracellular localization of the nuclear encoded D-CDes protein in the mitochondria. D-CDes RNA levels increased with proceeding development of Arabidopsis but decreased in senescent plants D-CDes protein levels remained almost unchanged in the same plants whereas