کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2030139 1071042 2006 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flexibility of Thiamine Diphosphate Revealed by Kinetic Crystallographic Studies of the Reaction of Pyruvate-Ferredoxin Oxidoreductase with Pyruvate
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Flexibility of Thiamine Diphosphate Revealed by Kinetic Crystallographic Studies of the Reaction of Pyruvate-Ferredoxin Oxidoreductase with Pyruvate
چکیده انگلیسی

SummaryPyruvate-ferredoxin oxidoreductases (PFOR) are unique among thiamine pyrophosphate (ThDP)-containing enzymes in giving rise to a rather stable cofactor-based free-radical species upon the decarboxylation of their first substrate, pyruvate. We have obtained snapshots of unreacted and partially reacted (probably as a tetrahedral intermediate) pyruvate-PFOR complexes at different time intervals. We conclude that pyruvate decarboxylation involves very limited substrate-to-product movements but a significant displacement of the thiazolium moiety of ThDP. In this respect, PFOR seems to differ substantially from other ThDP-containing enzymes, such as transketolase and pyruvate decarboxylase. In addition, exposure of PFOR to oxygen in the presence of pyruvate results in significant inhibition of catalytic activity, both in solution and in the crystals. Examination of the crystal structure of inhibited PFOR suggests that the loss of activity results from oxime formation at the 4′ amino substituent of the pyrimidine moiety of ThDP.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 14, Issue 2, 2 February 2006, Pages 217–224
نویسندگان
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