REAGENT or RESOURCE	SOURCE	IDENTIFIER
Bacterial and virus strains
E.coli BL21 (DE3)	Agilent	Cat#200131
Chemicals, peptides, and recombinant proteins
eNP-2 (25-457) recombinant proteins	Leung et al., 2015; Su et al., 2018	N/A
uranyl acetate	Electron Microscopy Sciences	Cat#22400
Tobacco Etch Virus protease (TEV Protease)	New England Biolabs	Cat#P8112S
Deposited data
Cryo-EM map for eNP-2	This Paper	https://www.ebi.ac.uk/pdbe/entry/emdb/EMD-7343
Flexible fitted models of eNP-2 to cryoEM map	Su et al., 2018	N/A
Recombinant DNA
Plasmid pMBP-His6TEV eNP-2	Leung et al., 2015; Su et al., 2018	N/A
Software and algorithms
Origin	OriginLab	https://www.originlab.com (Version 7)
PRISM	GraphPad	https://www.graphpad.com/ (Version 7)
UCSF Chimera	Pettersen et al., 2004	http://www.cgl.ucsf.edu/
EMAN2	Tang et al., 2007	http://blake.bcm.edu/emanwiki/EMAN2
Relion2	Scheres, 2012; He and Scheres., 2017	www2.mrc-lmb.cam.ac.uk/relion
Motioncorr v2.1	Li et al., 2013	https://github.com/jianglab/motioncorr
CTFFIND4	Rohou and Grigorieff., 2015	http://grigoriefflab.janelia.org/ctf
EMAN	Ludtke et al., 1999	http://blake.bcm.edu/emanwiki/EMAN1
IHRSR	Egelman, 2007	https://cryoem.ucsd.edu/wikis/software/start.php?id=ihrsr
Segger and ProMod plugin in UCSF Chimera	Pintilie et al., 2010 Pintilie et al., 2016	https://github.com/gregdp/segger
MassMatrix	Xu and Freitas, 2009	http://www.massmatrix.bio/
HDExaminer	Sierra Analytics, Modesto, CA	http://massspec.com/hdexaminer/
MDFF	Trabuco et al., 2009	http://www.ks.uiuc.edu/Research/mdff/
ProMod	Peitsch, 1996	https://pypi.org/project/promod/
PSIPRED	McGuffin et al., 2000	http://bioinf.cs.ucl.ac.uk/psipred/
Other
Cu grids with continuous carbon film	Ted Pella	Cat#01754-F
Quantifoil R 1.2/1.3 Cu grids (with continuous carbon film	Quantifoil	Cat#Q325CR1.3