Accumulation on the Cyioplasmic Membrane of the Precursor to Dimethyl Sulfoxide Reductase in Molybdenum Cofactor-Deficient Mutants of Rhodobacter sphaeroides f. sp. denitnficans

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概要

• 論文の詳細を見る

• The role of the molybdenum cofactor (MO cofactor) in the translocation of dimethyl sulfoxide (DMSO) reductase to the periplasmic space was studied in vivo by isolating chlorate-resistant mutants of Rhodobacter sphaeroides f. sp. denitrificans. More than 50% of the chlorate-resistant mutants isolated were defective in the biosynthesis of the Mo cofactor and all of these mutants accumulated the precursor form of the enzyme. About 45% of the mutants contained the same level of Mo cofactor as the parent strain and exhibited normal levels of DMSO reductase and nitrate reductase activities when chlorate was absent from the medium, but the activities of these enzymes were depressed when chlorate was present. Much of the accumulated precursor form of the enzyme in a Mo cofactor-deficient mutant was bound to the cytoplasmic membrane and was sensitive to treatment with proteinase K from the periplasmic side of the membrane, an indication that the precursor was exposed on the periplasmic surface of the membrane. The precursor accumulated on the membrane of the parent strain when molybdate was removed from the medium or upon addition of tungstate and this precursor was also sensitive to the treatment with proteinase K from the periplasmic side. These results suggest that the Mo cofactor is necessary for proteolytic processing of the precursor to the mature enzyme on the periplasmic side of the membrane, whereas binding of the precursor to the membrane and translocation across it can occur in the absence of the cofactor. Almost all of the Mo cofactor available for direct reconstitution in vitro of nitrate reductase activity from the nit-1 mutant of Neurospora crassa was present in the cytoplasmic fractions.

• 日本植物生理学会の論文

著者

• Masui H

  Hiroshima Univ. Higashi‐hiroshima Jpn

• Satoh T

  Botanical Institute Faculty Of Science Hiroshima University

• Masui Hideo

  Botanical Institute, Faculty of Science, Hiroshima University

• Fukase Yasuko

  Botanical Institute, Faculty of Science, Hiroshima University

• Satoh Toshio

  Botanical Institute, Faculty of Science, Hiroshima University

• Fukase Yasuko

  Botanical Institute Faculty Of Science Hiroshima University

• Satoh Toshio

  Botanical Institute Faculty Of Science Hiroshima University

関連論文

• Stabilization by GroEL, a Molecular Chaperone, and a Periplasmic Fraction, as Well as Refolding in the Presence of Dithiothreitol, of Acid-Unfolded Dimethyl Sulfoxide Reductase, a Periplasmic Protein of Rhodobacter sphaeroides f. sp. denitrificans
• A Novel Molybdenum Protein with a Low Molecular Mass in Rhodobacter sphaeroides f.sp. denitrificans
• Accumulation on the Cyioplasmic Membrane of the Precursor to Dimethyl Sulfoxide Reductase in Molybdenum Cofactor-Deficient Mutants of Rhodobacter sphaeroides f. sp. denitnficans
• UNFOLDING AND REFOLDING IN VITRO OF THEPERIPLASMIC DMSO REDUCTASE OF RHODOBACTER SPHAEROIDES F. SP.DENITRIFICANS

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