tailieunhanh - Báo cáo khoa học: The molecular basis of heme oxygenase deficiency in the pcd1 mutant of pea

Thepcd1mutant of pea lacks heme oxygenase (HO) activity required for the synthesis of the phytochrome chromophore and is consequently severely deficient in all responses mediated by the phytochrome family of plant photoreceptors. Here we describe the isolation of the gene encoding pea heme oxygenase 1 (PsHO1) and confirm the presence of a mutation in this gene in the pcd1 mutant. | iFEBS Journal The molecular basis of heme oxygenase deficiency in the pcdl mutant of pea Philip J. Linley1 z Martin Landsberger1 Takayuki Kohchi2 Jon B. Cooper1 and Matthew J. Terry1 1 Schoolof BiologicalSciences University of Southampton UK 2 Graduate Schoolof Biostudies Kyoto University Sakyo Japan Keywords biliverdin photomorphogenesis phytochrome plastid structuralmodelling Correspondence M. J. Terry Schoolof BiologicalSciences University of Southampton Bassett Crescent East Southampton SO16 7PX UK Fax 44 2380 594459 Tel 44 2380 592030 E-mail mjt@ http Present address Graduate Schoolof Biostudies Kyoto University Sakyo Kyoto 606-8502 Japan TAG Molekulare Kardiologie Klinik fur Innere Medizin B Universitat Greifswald 17487 Greifswald Germany Database The nucleotide sequences data for pea HO1 are available in the DDBJ EMBL GenBank databases under the accession numbers AF276228 HO cDNA AF276229 HO1 genomic sequence from cultivar Solara AF276230 HO1 genomic sequence from cultivar Torsdag . Received 23 January 2006 revised 17 March 2006 accepted 7 April 2006 doi The pcdl mutant of pea lacks heme oxygenase HO activity required for the synthesis of the phytochrome chromophore and is consequently severely deficient in all responses mediated by the phytochrome family of plant photoreceptors. Here we describe the isolation of the gene encoding pea heme oxygenase 1 PsHOl and confirm the presence of a mutation in this gene in the pcdl mutant. PsHO1 shows a high degree of sequence homology to other higher plant HOs in particular with those from other legume species. Expression of PsHOl increased in response to white light but did not respond strongly to narrow band light treatments. Analysis of the biochemical activity of PsHO1 expressed in Escherichia coli demonstrated requirements for reduced ferredoxin a secondary reductant such as ascorbate and an iron chelator for maximum enzyme activity. Using the crystal