Russian Journal of Biological Physics and Chemisrty Russian Journal of Biological Physics and Chemisrty АКТУАЛЬНЫЕ ВОПРОСЫ БИОЛОГИЧЕСКОЙ ФИЗИКИ И ХИМИИ 2499-9962 54240 Общая биофизика General biophysics Общая биофизика STUDIES OF THE EFFECT OF FLEXIBILITY OF THE POLYPEPTIDE CHAIN OF PROTEIN ON THE ENERGY PROFILE OF APOMYOGLOBIN ИССЛЕДОВАНИЕ ВЛИЯНИЯ ГИБКОСТИ ОСНОВНОЙ ЦЕПИ БЕЛКА НА ЭНЕРГЕТИЧЕСКИЙ ПРОФИЛЬ АПОМИОГЛОБИНА Мажорина М А Majorina M A MariaMazhorina@yandex.ru Мельник Б С Melnik B S Институт белка РАН ru Institute of protein research, Russian Academy of Sciences ru Институт белка РАН ru Institute of protein research, Russian Academy of Sciences ru 25 03 2018 25 03 2018 3 1 34 38 20 03 2018 20 03 2018 https://rusjbpc.ru/en/nauka/article/54240/view

Апомиоглобин - удобная модель для in vitro исследований сворачивания/разворачивания глобулярных белков. В данной работе представлены результаты кинетических исследований сворачивания/разворачивания мутантных форм апомиоглобина с заменами остатков пролина в двух его петлях на глицин (P37G и P120G), а также удлинение петли (в положении 120) на три и шесть остатков глицина (P120(3G) и P120(6G)). Для всех белков измерены кинетические кривые денатурации и ренатурации, рассчитаны константы скоростей сворачивания/разворачивания, построены их зависимости от концентрации денатуранта (шевронные графики), рассчитаны свободные энергии всех состояний апомиоглобина. Полученные данные о кинетических свойствах мутантных форм апомиоглобина позволили изучить влияние гибкости и длины выбранных петель на энергетический профиль белка. В частности, показано, что все исследованные мутации дестабилизировали промежуточное состояние апомиоглобина относительно развернутого состояния.

Apomyoglobin is a convenient model for in vitro studies of folding/unfolding of globular proteins. Herein we describe the results of kinetic studies of folding/unfolding of mutant forms of apomyoglobin with substitutions of proline residues on its two loops (P37G and P120G) by glycine as well as loop extension in position 120 by three and six glycine residues (P120(3G) and P120(6G)). For all proteins, we measured kinetic denaturation and renaturation curves, calculated rate constants of folding/unfolding, plotted their dependences on the denaturant concentration (chevron plots) and computed free energies of all states of apomyoglobin. The obtained data on the kinetic properties of mutant forms of apomyoglobin allowed us to analyze the effect of flexibility and length of chosen loops on the energy profile of the protein. Specifically, it was demonstrated that the studied mutations destabilized the intermediate state of apomyoglobin as compared to the unfolded state.

 апомиоглобин сворачивание белка триптофановая флуоресценция эксперименты остановленного потока шевронный график энергетический профиль apomyoglobin protein folding tryptophan fluorescence stopped-flow experiments chevron plot energy profile

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