کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9882419 | 1536557 | 2005 | 19 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structure-function studies on the iron-sulfur flavoenzyme glutamate synthase: an unexpectedly complex self-regulated enzyme
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Glutamate synthase (GltS) is, with glutamine synthetase, the key enzyme of ammonia assimilation in bacteria, microorganisms and plants. GltS isoforms result from the assembly and co-evolution of conserved functional domains. They share a common mechanism of reductive glutamine-dependent glutamate synthesis from 2-oxoglutarate, which takes place within the α subunit (â¼150 kDa) of the NADPH-dependent bacterial enzyme and the corresponding polypeptides of other GltS forms, and involves: (i) an Ntn-type amidotransferase domain and (ii) a flavin mononucleotide-containing (β/α)8 barrel synthase domain connected by (iii) a â¼30 Ã
-long intramolecular ammonia tunnel. The synthase domain harbors the [3Fe/4S]0,+1 cluster of the enzyme, which participates in the electron transfer process from the physiological reductant: reduced ferredoxin in the plant-type enzyme or NAD(P)H in the bacterial and the non-photosynthetic eukaryotic form. The NAD(P)H-dependent GltS requires a tightly bound flavin adenine dinucleotide-dependent reductase (β subunit, â¼50 kDa), also determining the presence of two low-potential [4Fe-4S]+1,+2 clusters. Structural, functional and computational data available on GltS and related enzymes show how the enzyme may control and coordinate the reactions taking place at the glutaminase and synthase sites by sensing substrate binding and cofactor redox state.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 433, Issue 1, 1 January 2005, Pages 193-211
Journal: Archives of Biochemistry and Biophysics - Volume 433, Issue 1, 1 January 2005, Pages 193-211
نویسندگان
Maria A. Vanoni, Bruno Curti,