# INTERACTION OF MYOSIN WITH ACTIN

> **NIH NIH R01** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 1987 · $117,838

## Abstract

During muscular contraction myosin crossbridge and actin filament enter
into cyclic interaction which ultimately results in tension development.
The energy source for this mechanical work is the free energy released from
ATP hydrolysis catalyzed by actomyosin.  Most of the free energy drop
appears to be associated with substrate binding to myosin.  The mechanism
by which energy is transduced in muscle is poorly understood.  During
catalysis and upon binding to actin the myosin structure undergoes
structural changes and these changes are believed to play an important role
in the overall contractile mechanism.  The proposed research will
investigate certain structural aspects of skeletal myosin subfragment-1
(S-1) which contains both the substrate and actin binding sites and changes
of these structural features induced by nucleotide and actin binding.  The
presteady state kinetics of the acto-S-1 ATPase will also be investigated.
Proximity relationship of S-1 will be investigated by fluorescence energy
transfer (FET) and its solution conformation by other fluorescence methods
with both extrinsic and intrinsic fluorophores.  The role of S-1 heavy
chain in myosin function will be investigated by examining the effect of
its limited cleavage on the chemical reactivity and structure of S-1, and
the dynamic nature of the S-1 active site region.  Fluorescence
spectroscopic techniques will be used for these studies.  The folding of
S-1 heavy chain will be studied by using crosslinking reagents with
specificities for lysyl and sulfhydryl groups.  Finally, the kinetic
mechanism for the interaction of S-1 with actin will be elucidated by using
stopped flow FET and fluorescence polarization.  The presteady state
kinetics of S-1 ATPase and acto S-1 ATPase will be investigated by FET with
fluorescent substrates.  These kinetic studies will be performed with
special attention paid to the possible role of the DTNB light chain in the
kinetic events.

## Key facts

- **NIH application ID:** 3156008
- **Project number:** 5R01AR031239-05
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **SAM.gov UEI:** YND4PLMC9AN7
- **Principal Investigator:** HERBERT C CHEUNG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $117,838
- **Award type:** 5
- **Project period:** 1983-08-01 → 1989-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156008

## Citation

> US National Institutes of Health, RePORTER application 3156008, INTERACTION OF MYOSIN WITH ACTIN (5R01AR031239-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3156008. Licensed CC0.

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