An actin filament contacting myosin molecules as a functional unit of muscle contraction induces magnetic dipoles along the filament when ATP molecules to be hydrolyzed are available there. The induced magnetic dipoles are coherent over the entire filament, though they are fluctuating altogether as constantly being subject to the ambient thermal agitations.
@article{arxiv.quant-ph/0104042,
title = {Magnetic Dipoles and Quantum Coherence in Muscle Contraction},
author = {Kuniyuki Hatori and Hajime Honda and Koichiro Matsuno},
journal= {arXiv preprint arXiv:quant-ph/0104042},
year = {2007}
}