کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
30121 44460 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A combined binding mechanism of nonionic ethoxylated surfactants to bovine serum albumin revealed by fluorescence and circular dichroism
ترجمه فارسی عنوان
مکانیکی اتصال مکانیکی سورفکتانتهای اتوکسیل نشده غیر آلی به آلبومین سرم گاو نشان داده شده توسط فلورسانس و دی کروموزوم دایره ای
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
چکیده انگلیسی


• BSA is studied in interaction with C12En (n = 4,6,8) and C14EO20 respectively.
• H bonding governs the interaction next to the hydrophobic attraction.
• Zigzag conformation of ethyleneoxide chains (n = 4–8) allows more H bonds with BSA.
• An apparent inter-conversion of the Trp rotamers occurs around the CMC of C12En.
• Association constants, binding isotherms and thermodynamic parameters are given.

The study systematically investigates aqueous mixtures of fixed bovine serum albumin (BSA) and various ethoxylated nonionic surfactants belonging to a homologous series or not. Mono-disperse tetra-(C12E4), hexa-(C12E6) and octa-ethyleneglycol mono-n-dodecyl ether (C12E8), and poly-disperse eicosa-ethyleneglycol mono-n-tetradecyl ether (C14EO20) are respectively employed. Fluorescence and circular dichroism measurements are performed at surfactant/protein molar ratios (rm)s lower and higher than one. We aim to get new insights into the binding mechanism of these species and to differentiate among the interaction abilities of these surfactants. The relative magnitude of the binding thermodynamic parameters by fluorescence, and the increase of α-helix prove that hydrogen bonding drives the interaction next to the hydrophobic attraction. C12En (n = 4,6,8) develop more H bonds with the albumin than C14EO20 owing to a zigzag conformation of their short ethyleneoxide chains. Among the homologous surfactants, C12E6 has a slightly stronger interaction with BSA due to a maximal number of H bonds at a minimal hindering. Static fluorescence and dynamic fluorescence indicate an inter-conversion between the tryptophan (Trp) rotamers which happens around the surfactants critical micellar concentration. For C14EO20, the meander conformation of the polar group determines a less evident conversion of the Trp rotamers and smaller α-helix rise. Binding isotherms of the homologous surfactants and the fluorescence quenching mechanism by C12E6 are also provided.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 153, December 2015, Pages 198–205
نویسندگان
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