REAGENT or RESOURCE	SOURCE	IDENTIFIER
Biological samples
Mouse fast psoas myofibrils from a 3-month female BALB/c mouse	King’s College London	N/A
Deposited data
Sub-volume average of in situ actomyosin complex	This paper	EMD: 12289
Sub-volume average of re-centered myosin double-head	This paper	EMD: 12291
Sub-volume average of I-band thin filaments without troponin	This paper	EMD: 12292
Sub-volume average of I-band thin filaments including troponin	This paper	EMD: 12293
Homology model of in situ actomyosin complex	This paper	PDB: 7NEP
Cryo-EM structure of in vitro cytoplasmic actomyosin complex	von der Ecken et al., 2016	PDB: 5JLH
Crystal structure of rigor-like squid myosin S1 fragment	Yang et al., 2007	PDB: 3I5G
Cryo-EM structure of human cardiac thin filament in calcium-bound state	Yamada et al., 2020	PDB: 6KN8
Cryo-EM structure of human cardiac thin filament in calcium-free state	Yamada et al., 2020	PDB: 6KN7
Cryo-EM structure of relaxed myosin heads in insect flight muscle	Hu et al., 2016; Knupp et al., 2019	PDB: 6SO3
Crystal structure of human myosin S2 fragment	Blankenfeldt et al., 2006	PDB: 2FXM
Crystal structure of human α-actinin 2	Ribeiro et al., 2014	PDB: 4D1E
Cryo-EM structure of actin filament decorated by filamin A CH1 domain	Iwamoto et al., 2018	PDB: 6D8C
Software and algorithms
SerialEM	Mastronarde, 2005	https://bio3d.colorado.edu/SerialEM/
MotionCorr2	Zheng et al., 2017	https://emcore.ucsf.edu/ucsf-software
EMAN2	Tang et al., 2007	https://blake.bcm.edu/emanwiki/EMAN2
IMOD	Kremer et al., 1996	https://bio3d.colorado.edu/imod/
crYOLO	Wagner et al., 2019	https://cryolo.readthedocs.io
RELION3	Bharat and Scheres, 2016	https://www3.mrc-lmb.cam.ac.uk/relion/index.php?title=Main_Page
PEET	Heumann et al., 2011; Nicastro et al., 2006	https://bio3d.colorado.edu/PEET/
ISAC	Yang et al., 2012	http://sphire.mpg.de/wiki/doku.php?id=gpu_isac
SPHIRE	Moriya et al., 2017	https://sphire.mpg.de/
TrackMate plug-in in Fiji	Tinevez et al., 2017	https://imagej.net/TrackMate
Fiji (ImageJ)	Schindelin et al., 2012; Schneider et al., 2012	https://imagej.net/Fiji
TEMPy	Farabella et al., 2015	http://tempy.ismb.lon.ac.uk/
SWISS-MODEL	Bertoni et al., 2017; Bienert et al., 2017; Guex et al., 2009; Studer et al., 2020; Waterhouse et al., 2018	https://swissmodel.expasy.org/
Chimera	Pettersen et al., 2004	https://www.cgl.ucsf.edu/chimera/
Amira2019.3	Thermo Fisher Scientific	https://www.thermofisher.com/us/en/home/industrial/electron-microscopy/electron-microscopy-instruments-workflow-solutions/3d-visualization-analysis-software/amira-life-sciences-biomedical.html
MUSCLE algorithm in msa R package	Edgar, 2004	https://www.rdocumentation.org/packages/msa