کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9886130 | 1537496 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Isolation and spectroscopic characterization of the membrane-bound nitrate reductase from Pseudomonas chlororaphis DSM 50135
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
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![عکس صفحه اول مقاله: Isolation and spectroscopic characterization of the membrane-bound nitrate reductase from Pseudomonas chlororaphis DSM 50135 Isolation and spectroscopic characterization of the membrane-bound nitrate reductase from Pseudomonas chlororaphis DSM 50135](/preview/png/9886130.png)
چکیده انگلیسی
A nitrate reductase was solubilized with Triton X-100 from the membranes of Pseudomonas chlororaphis DSM 50135 grown microaerobically in the presence of nitrate. Like other membrane-bound nitrate reductases, it contains three subunits, of 129, 66 (64) and 24 kDa, referred to in the literature as α, β and γ, respectively. Electrocatalytic studies revealed that only the membrane-bound, not the solubilized form of the enzyme, can accept electrons from a menaquinone analog, menadione, whereas both forms can accept electrons from methylviologen. The isolated enzyme possesses several iron-sulfur clusters and a molybdopterin guanine dinucleotide active center. The iron-sulfur clusters can be grouped in two classes according to their redox properties, the high-potential and low-potential clusters. In the as-isolated enzyme, two forms of the molybdenum center, high- and low-pH, are detectable by electron paramagnetic resonance spectroscopy. The low-pH form shows a hyperfine splitting due to a proton, suggesting the presence of an -OHx ligand. Dithionite reduces the Mo(V) center to Mo(IV) and subsequent reoxidization with nitrate originates a new Mo(V) signal, identical to the oxidized low-pH form but lacking its characteristic hyperfine splitting. The isolated preparation also contains heme c (in a sub-stoichiometric amount) with the ability to relay electrons to the molybdenum center, suggesting that this nitrate reductase may contain heme c instead of the heme b usually found in this class of enzymes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1723, Issues 1â3, 25 May 2005, Pages 151-162
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1723, Issues 1â3, 25 May 2005, Pages 151-162
نویسندگان
Dora Pinho, Stéphane Besson, Pedro J. Silva, Baltazar de Castro, Isabel Moura,