Document Detail

Fundamental step size in single cardiac and skeletal sarcomeres.
MedLine Citation:
PMID:  12176730     Owner:  NLM     Status:  MEDLINE    
In attempting to deduce the size of the elementary molecular translation step, recent experiments using single myosin molecules translating over actin filaments have shown a consistent step size of 5.4 nm (10, 21). We have carried out parallel measurements on single myofibrils from rabbit cardiac muscle and bumblebee flight muscle. Activated specimens were released or stretched with a motor-imposed ramp, and the time course of length of individual sarcomeres was measured by projecting the image of the striations onto a linear photodiode array and tracking the spacing between A-band centroids. We confirmed the 5.4-nm step. With subnanometer precision, however, we find that this value is two times that of a more fundamental step size of 2.7 nm. Step sizes were always integer multiples of 2.7 nm, whether the length change was positive or negative. This value is equal to the linear repeat of actin monomers along the thin filament, a result that ties dynamic events to molecular structure and places narrow constraints on any proposed molecular mechanism.
Olga Yakovenko; Felix Blyakhman; Gerald H Pollack
Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article    
Journal Detail:
Title:  American journal of physiology. Cell physiology     Volume:  283     ISSN:  0363-6143     ISO Abbreviation:  Am. J. Physiol., Cell Physiol.     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-08-14     Completed Date:  2002-09-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901225     Medline TA:  Am J Physiol Cell Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  C735-42     Citation Subset:  IM    
Department of Bioengineering, University of Washington, Seattle 98195, USA.
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MeSH Terms
Biophysical Phenomena
Heart Ventricles / ultrastructure
Image Processing, Computer-Assisted
Microscopy / methods
Muscle Contraction / physiology*
Muscle, Skeletal / physiology,  ultrastructure
Myofibrils / physiology*,  ultrastructure
Reproducibility of Results
Sarcomeres / physiology*,  ultrastructure
Sensitivity and Specificity
Ventricular Function

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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