Extended Data Fig. 1: Molecular design of the printable active network.
From: A printable active network actuator built from an engineered biomolecular motor
a, Myosin in muscle sarcomeres. Myosin II has two functional domains, heavy meromyosin (HMM) and light meromyosin (LMM). The main role of HMM is to propel actin filaments, whereas the LMM domain promotes myosin filament formation. In a muscle sarcomere, myosin II forms bipolar filaments and assembles them into a highly-ordered interlocked structure with actin filaments and other proteins. Sarcomeres contract through sliding of the actin filaments caused by myosin conformational changes. b, Design of fusion proteins for the printable active network. CaMLMM is a genetically engineered fusion protein of calmodulin (CaM) and LMM. This fusion protein assembles into filaments and serves as a calcium-activated scaffold for proteins possessing a calmodulin binding sequence. K465m13 is a kinesin I truncation (aa 1–465) with the m13 CaM binding sequence of the myosin light chain kinase (MLCK) at the C-terminus. c, Filament formation of CaMLMM. CaMLMM forms filaments similar to myosin filaments in low-salt conditions. d, Assembly of kinesin filaments triggered by UV irradiation. UV irradiation causes an influx of calcium ions released from caged molecules and results in the decoration of CaMLMM filaments by K465m13 fusion protein units. e, Contraction. Kinesin filaments induce the sliding of microtubules and further dynamic self-assembly into a contractile network.
