These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Formation of reverse rigor chevrons by myosin heads.
    Author: Reedy MC, Beall C, Fyrberg E.
    Journal: Nature; 1989 Jun 08; 339(6224):481-3. PubMed ID: 2725681.
    Abstract:
    The uniform angle and conformation of myosin subfragment 1 (S1) bound to actin filaments (F-actin) attest to the precise alignment and stereospecificity of the binding of these two contractile proteins. Because actin filaments are polar, myosin heads must swing or rotate about the head-tail junction in order to bind. Electron microscopy of isolated thick filaments and of myosin molecules suggests that the molecules are flexible, but myosin fragments and crossbridges have been reported not to interact with inappropriately oriented actin filaments. Here we describe myofibrillar defects engendered by a site-directed mutation within the flight-muscle-specific actin gene of the fruitfly Drosophila. The mutation apparently retards sarcomere assembly: peripheral thick and thin filaments are misregistered and not incorporated into the Z-line. Therefore, a myosin filament encounters thin filaments with the 'wrong' polarity. We show that myosin heads tethered in a single thick filament can bind with opposite rigor crossbridge angles to flanking thin filaments, which are apparently of opposite polarities. Preservation of identical actomyosin interfaces requires that sets of heads originating from opposite sides of the thick filament swivel 180 degrees relative to each other, implying that myosin crossbridges are as flexible as isolated molecules.
    [Abstract] [Full Text] [Related] [New Search]