Two operational modes of atomic force microscopy reveal similar mechanical properties for homologous regions of dystrophin and utrophin.

Autor:	Hua C; Department of Electrical and Computer Engineering, University of Minnesota - Twin Cities, Minneapolis, MN., Slick RA; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota - Twin Cities, Minneapolis, MN., Vavra J; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota - Twin Cities, Minneapolis, MN., Muretta JM; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota - Twin Cities, Minneapolis, MN., Ervasti JM; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota - Twin Cities, Minneapolis, MN., Salapaka MV; Department of Electrical and Computer Engineering, University of Minnesota - Twin Cities, Minneapolis, MN.
Jazyk:	angličtina
Zdroj:	BioRxiv : the preprint server for biology [bioRxiv] 2024 May 20. Date of Electronic Publication: 2024 May 20.
DOI:	10.1101/2024.05.18.593686
Abstrakt:	Duchenne muscular dystrophy (DMD) is a lethal muscle disease caused by the absence of the protein dystrophin. Dystrophin is hypothesized to work as a molecular shock absorber that limits myofiber membrane damage when undergoing reversible unfolding upon muscle stretching and contraction. Utrophin is a dystrophin homologue that is under investigation as a protein replacement therapy for DMD. However, it remains uncertain whether utrophin can mechanically substitute for dystrophin. Here, we compared the mechanical properties of homologous utrophin and dystrophin fragments encoding the N terminus through spectrin repeat 3 (UtrN-R3, DysN-R3) using two operational modes of atomic force microscopy (AFM), constant speed and constant force. Our comprehensive data, including the statistics of force magnitude at which the folded domains unfold in constant speed mode and the time of unfolding statistics in constant force mode, show consistent results. We recover parameters of the energy landscape of the domains and conducted Monte Carlo simulations which corroborate the conclusions drawn from experimental data. Our results confirm that UtrN-R3 expressed in bacteria exhibits significantly lower mechanical stiffness compared to insect UtrN-R3, while the mechanical stiffness of the homologous region of dystrophin (DysN-R3) is intermediate between bacterial and insect UtrN-R3, showing greater similarity to bacterial UtrN-R3. Competing Interests: Declaration of interests The authors declare no competing interests.
Databáze:	MEDLINE
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