Covalent cross-linking of single fibers from rabbit psoas increases oscillatory power

Single fibers from chemically skinned rabbit psoas muscle were treated with 1-ethyl-3-[3-dimethyl-amino)proyl]-carbodiimide (EDC) at 20 degrees C after rigor was induced. A 22-min treatment resulted in 18% covalent cross-linking between myosin heads and the thin filament as determined by stiffness m...

Full description

Saved in:
Bibliographic Details
Published in:Biophysical journal 1990-03, Vol.57 (3), p.643-647
Main Authors: Tawada, K., Kawai, M.
Format: Article
Language:English
Subjects:
Animals
Carbodiimides - pharmacology
Elasticity
Ethyldimethylaminopropyl Carbodiimide - pharmacology
In Vitro Techniques
Models, Biological
Muscle Contraction - drug effects
Muscles - drug effects
Muscles - physiology
Rabbits
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Single fibers from chemically skinned rabbit psoas muscle were treated with 1-ethyl-3-[3-dimethyl-amino)proyl]-carbodiimide (EDC) at 20 degrees C after rigor was induced. A 22-min treatment resulted in 18% covalent cross-linking between myosin heads and the thin filament as determined by stiffness measurements. This treatment also results in covalent cross-linking among rod portions of myosin molecules in the backbone of the thick filament. The fibers thus prepared are stable and do not dissolve in solutions at ionic strengths as high as 1,000 mM. The preparation was subjected to sinusoidal analysis, and the resulting complex modulus data were analyzed in terms of three exponential processes, (A), (B), and (C). Oscillatory work (process B) was much greater in the cross-linked fibers than in untreated ones in activating solutions of physiological ionic strength (200 mM); this difference was attributed to the decline of process (A) with EDC treatment. Consequently, the Nyquist plot of the EDC-treated preparation exhibited an insect-type response. We conclude that, under these conditions, both cross-linked and non-cross-linked myosin heads contribute to the production of oscillatory power. The cross-linked preparations also exhibited oscillatory work in high ionic strength (500–1,000 mM) solutions, indicating that cross-linked myosin heads are capable of utilizing ATP to produce work. We conclude that process (A) does not relate to an elementary step in a cross-bridge cycle, but it may relate to dynamics outside the cross-bridge such as filament sliding or sarcomere rearrangement.
ISSN:0006-3495
1542-0086
DOI:10.1016/S0006-3495(90)82582-0