# MUSCLE PROTEINS USING PARAMAGNETIC PROBES

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 1990 · $179,392

## Abstract

The long-range goal of our research is to elucidate the molecular
mechanisms involved in he interaction of myosin, actin and ATP.  In the
most prevalent hypothesis a myosin head generates force by rotating while
attached to actin.  Paramagnetic probes are excellent tools for
investigating the contractile mechanism, because both their angular
distribution and their motion can be measured from their spectra.  We will
extend our previous studies of probes bound to both actin and myosin head
consists of a large mass at its distal end, which attaches to actin.  This
is connected to the rod by a more slender neck about 10 nm in length.
Previous studies of paramagnetic probes on the distal region suggest that
it doesn't rotate to generate force, thus implicating the neck region of
myosin in the generation of force.  The light chains of myosin are located
in the neck region.  We have recently attached probes to one site on a
purified myosin light chain exchanged it into fibers and found that this
region is more flexible than the distal end.  Similar techniques will be
used to find additional probe sites on light chains and to thus
characterize the orientation and motion of myosin at a variety of sites.
Data from these sites should provide a detailed picture of the motion and
orientation of the myosin head during force generation.  In another project
we will investigate cooperative interactions between the two heads of
myosin.  We will trap spin-labeled nucleotides on myosin heads, eliminating
their interaction with actin, and we will use this preparation to determine
the mechanical properties of myosin molecules that are generating force
with only one head.  We will also probe conformational changes occurring in
actin during its interaction with other proteins:  myosin, DNAse I and the
regulatory proteins.  A high resolution structure of an actin-DNAse complex
is nearing completion, making it particularly pertinent to determine
whether the bond with DNAse alters the conformation of actin.  Knowledge of
how force is produced and how it is controlled in striated muscle,
especially in cardiac muscle, will help define more rational therapies for
treating disorders in these muscles.

## Key facts

- **NIH application ID:** 3155912
- **Project number:** 2R01AR030868-09
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **SAM.gov UEI:** KMH5K9V7S518
- **Principal Investigator:** Roger A Cooke
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $179,392
- **Award type:** 2
- **Project period:** 1982-04-01 → 1995-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3155912

## Citation

> US National Institutes of Health, RePORTER application 3155912, MUSCLE PROTEINS USING PARAMAGNETIC PROBES (2R01AR030868-09). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3155912. Licensed CC0.

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