کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2039242 1073039 2016 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Work Done by Titin Protein Folding Assists Muscle Contraction
ترجمه فارسی عنوان
کار انجام شده توسط تیتین پروتئین تاشو کمک به انقباض عضلات
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم کشاورزی و بیولوژیک (عمومی)
چکیده انگلیسی


• Titin Ig domains unfold and refold continuously at physiological sarcomere lengths
• Refolding of titin domains generates mechanical work that assists muscle contraction
• Titin and myosin motors operate as an inextricable molecular system in muscle

SummaryCurrent theories of muscle contraction propose that the power stroke of a myosin motor is the sole source of mechanical energy driving the sliding filaments of a contracting muscle. These models exclude titin, the largest protein in the human body, which determines the passive elasticity of muscles. Here, we show that stepwise unfolding/folding of titin immunoglobulin (Ig) domains occurs in the elastic I band region of intact myofibrils at physiological sarcomere lengths and forces of 6–8 pN. We use single-molecule techniques to demonstrate that unfolded titin Ig domains undergo a spontaneous stepwise folding contraction at forces below 10 pN, delivering up to 105 zJ of additional contractile energy, which is larger than the mechanical energy delivered by the power stroke of a myosin motor. Thus, it appears inescapable that folding of titin Ig domains is an important, but as yet unrecognized, contributor to the force generated by a contracting muscle.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 14, Issue 6, 16 February 2016, Pages 1339–1347
نویسندگان
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