Publication date: Available online 27 May 2017
Source:Biochimica et Biophysica Acta (BBA) - General Subjects
Author(s): András Bibó, György Károlyi, Mihály Kovács
Background:Myosin II, the motor protein driving muscle contraction, uses energy of ATP hydrolysis to produce movement along actin. The key step of energy transduction is the powerstroke, involving rotation of myosin’s lever while myosin is attached to actin. Macroscopic measurements indicated high thermodynamic efficiency for energy conversion. However, single-molecule experiments indicated lower efficiency, provoking a long-standing discrepancy.Methods:Based on the Fluctuation-Dissipation Theorem, we built a sufficiently detailed but low degree-of-freedom model reconstructing the entire mechanoenzymatic cycle.Results:We show that a high axial stiffness of the lever during an initial, experimentally yet unrevealed part of the powerstroke results in a short-time, ratchet-like Kramers effect, and is responsible for the missing efficiency. The second part of the powerstroke is an Eyring-like relaxation that dominantly contributes to lever rotation, but produces only a minor part of the work.Conclusions:The model reveals the structural background of myosin’s capability to function as a robust molecular engine and a very precise load sensor as well. Our model also suggests an explanation for the malfunction of myosins harboring mutations that lead to hypertrophic cardiomyopathies with most severe clinical prognosis.General Significance:The model explains how a force-transmitting device within a biological motor can enable high energetic efficiency.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2quNpWE
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
Abstract Objective To evaluate Chinese medicine (CM) formula Bazheng Powder (八正散) as an alternative therapeutic option for female patients...
-
Audiol Neurotol 2016;21:I-VI from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2pSmIj1 via IFTTT
-
Related Articles Screening for Atrial Fibrillation using Economical and accurate TechnologY (SAFETY)-a pilot study. BMJ Open. 2017 Ja...
-
Abstract Soil conditioners can be used to compensate for the insufficient soil nutrition and organic matter (OM) of arable soils. However, ...
-
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2iLKsRa via IFTTT
-
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2pnBoX1 via IFTTT
-
An amplitude-modulated and frequency-modulated (AM-FM) radar with an active reflector to produce high-accuracy distance measurements is prop...
-
Cushing's syndrome (CS) can be classified as adrenocorticotropic hormone (ACTH)-dependent or ACTH-independent depending on the ACTH leve...
-
CBN News Cancer Took Most of His Tongue, but This Pastor Is Still Singing ... CBN News A youth pastor in San Diego, California is not ...
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου