Involvement of a protein with molybdenum cofactor in the in vitro activation of nitrate reductase from a chlA mutant of Escherichia coli K12

Giordano, Gérard; Santini, Claire‐Lise; Saracino, Laurence; Iobbi, Chantal

doi:10.1016/0167-4838(87)90281-0

Cited by 7 publications

(5 citation statements)

References 34 publications

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“…The role of NarJ might, therefore, consist of holding apo‐NarG in a suitable open conformation to allow for the insertion of the molybdenum cofactor. This final step is probably mediated by a carrier protein (Amy and Rajagopalan, 1979; Giordano et al ., 1987; Schwarz et al ., 1997), which delivers the molybdenum cofactor to the NarGHJ ternary complex. Studies are currently in progress to identify the molybdenum cofactor carrier protein that could interact transiently with this complex.…”

Section: Discussionmentioning

confidence: 99%

NarJ is a specific chaperone required for molybdenum cofactor assembly in nitrate reductase A of Escherichia coli

Blasco

Santos

Magalon

et al. 1998

Molecular Microbiology

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SummaryThe formation of active membrane-bound nitrate reductase A in Escherichia coli requires the presence of three subunits, NarG, NarH and NarI, as well as a fourth protein, NarJ, that is not part of the active nitrate reductase. In narJ strains, both NarG and NarH subunits are associated in an unstable and inactive NarGH complex. A significant activation of this complex was observed in vitro after adding purified NarJ-6His polypeptide to the cell supernatant of a narJ strain. Once the apo-enzyme NarGHI of a narJ mutant has become anchored to the membrane via the NarI subunit, it cannot be reactivated by NarJ in vitro. NarJ protein specifically recognizes the catalytic NarG subunit. Fluorescence, electron paramagnetic resonance (EPR) spectroscopy and molybdenum quantification based on inductively coupled plasma emission spectroscopy (ICPES) clearly indicate that, in the absence of NarJ, no molybdenum cofactor is present in the NarGH complex. We propose that NarJ is a specific chaperone that binds to NarG and may thus keep it in an appropriate competent-open conformation for the molybdenum cofactor insertion to occur, resulting in a catalytically active enzyme. Upon insertion of the molybdenum cofactor into the apo-nitrate reductase, NarJ is then dissociated from the activated enzyme.

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Section: Discussionmentioning

confidence: 99%

NarJ is a specific chaperone required for molybdenum cofactor assembly in nitrate reductase A of Escherichia coli

Blasco

Santos

Magalon

et al. 1998

Molecular Microbiology

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126

111

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“…The role of NarJ might, therefore, be to hold apo-NarGH in a cofactor-insertion-competent conformation. This final step is probably mediated by a carrier protein [33,34], which delivers the cofactor to the NarGHJ ternary complex. In some cases, assembly of metallocentres appears to be a complex process requiring the action of several accessory gene products catalysing a whole maturation cascade in a specific order [35][36][37][38].…”

Section: Molybdenum Cofactor Insertionmentioning

confidence: 99%

The coordination and function of the redox centres of the membrane-bound nitrate reductases

Blasco¹,

Guigliarelli

Magalon³

et al. 2001

CMLS, Cell. Mol. Life Sci.

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Under anaerobic conditions and in the presence of nitrate, the facultative anaerobe Escherichia coli synthesises an electron-transport chain comprising a primary dehydrogenase and the terminal membrane-bound nitrate reductase A (NarGHI). This review focuses on recent advances obtained on the structure and function of the three protein subunits of membrane-bound nitrate reductases. We discuss a global architecture for the Mo-bisMGD-containing subunit (NarG) and a coordination model for the four [Fe-S] centres of the electron-transfer subunit (NarH) and for the two b-type haems of the anchor subunit NarI.

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“…In all cases the active compound(s) had an apparent M, < 1500 on a Sephadex G-50 column. Moreover, as for E. coli, the compound could be distinguished from the molybdenum cofactor by the fact that heated extracts of cells grown in the presence of tungstate, an antagonist of molybdate, were also active (Saracino et al, 1986;Giordano et al, 1987;Amy & Rajagopalan, 1979;Scott et al, 1979).…”

Section: Presence Of Low-m Factors Necessary For Activationmentioning

confidence: 99%

Escherichia coli Molybdoenzymes Can Be Activated by Protein FA from Several Gram-negative Bacteria

et al. 1989

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Six Gram-negative bacteria (Klebsiella pneumoniae, Erwinia chrysanthemi, Proteus vulgaris, Serratia marescens, Salmonella typhimurium, and Pseudomonas aeruginosa) were shown to contain an FA-type protein capable of activating aponitrate reductase, apotrimethylamine N-oxide reductase and apoformate dehydrogenase of Escherichia coli. Protein FA activity was highest in Erwinia chrysanthemi and lowest in Pseudomonas aeruginosa. All the species also contained the low-Mr (less than or equal to 1500) heat-resistant material previously reported to be necessary for the protein-FA-dependent activation of E. coli chlB nitrate reductase.

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Involvement of a protein with molybdenum cofactor in the in vitro activation of nitrate reductase from a chlA mutant of Escherichia coli K12

Cited by 7 publications

References 34 publications

NarJ is a specific chaperone required for molybdenum cofactor assembly in nitrate reductase A of Escherichia coli

NarJ is a specific chaperone required for molybdenum cofactor assembly in nitrate reductase A of Escherichia coli

The coordination and function of the redox centres of the membrane-bound nitrate reductases

Escherichia coli Molybdoenzymes Can Be Activated by Protein FA from Several Gram-negative Bacteria

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