کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5591526 1404979 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Substrate-analog binding and electrostatic surfaces of human manganese superoxide dismutase
ترجمه فارسی عنوان
سطوح متناوب آنالوگ و سطوح الکترواستاتیک سوپراکسید دیسموتاز منگنز انسانی
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شناسی مولکولی
چکیده انگلیسی
Superoxide dismutases (SODs) are enzymes that play a key role in protecting cells from toxic oxygen metabolites by disproportionation of two molecules of superoxide into molecular oxygen and hydrogen peroxide via cyclic reduction and oxidation at the active site metal. The azide anion is a potent competitive inhibitor that binds directly to the metal and is used as a substrate analog to superoxide in studies of SOD. The crystal structure of human MnSOD-azide complex was solved and shows the putative binding position of superoxide, providing a model for binding to the active site. Azide is bound end-on at the sixth coordinate position of the manganese ion. Tetrameric electrostatic surfaces were calculated incorporating accurate partial charges for the active site in three states, including a state with superoxide coordinated to the metal using the position of azide as a model. These show facilitation of the anionic ligand to the active site pit via a 'valley' of positively-charged surface patches. Surrounding ridges of negative charge help guide the superoxide anion. Within the active site pit, Arg173 and Glu162 further guide and align superoxide for efficient catalysis. Superoxide coordination at the sixth position causes the electrostatic surface of the active site pit to become nearly neutral. A model for electrostatic-mediated diffusion, and efficient binding of superoxide for catalysis is presented.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Biology - Volume 199, Issue 1, July 2017, Pages 68-75
نویسندگان
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