REAGENT or RESOURCE	SOURCE	IDENTIFIER
Biological samples
Naïve human serum	Sigma-Aldrich	Cat #H4522-100mL
Chemicals, peptides, and recombinant proteins
Papain from papaya latex	Sigma	CAS 9001-73-4
Tris base	VWR	CAS 77-86-1
EDTA tetrasodium salt	AMRESCO	CAS 13235-36-4
L-cysteine	Sigma-Aldrich	CAS 52-90-4
Iodoacetamide	Sigma-Aldrich	CAS 144-48-9
Uranyl formate hydrate	Electron Microscopy Sciences	Cat # 22541
Protein G resin sepharose 4 Fast Flow	Cytiva	17061805
rProtein A resin sepharose Fast Flow	Cytiva	17127903
Capture Select IgG-Fc affinity matrix	Thermo Scientific	191285550
Glycine	VWR	56-40-6
NaCl	Honeywell	Cat #S9888-10KG
NaOH	Fisher Scientific	UN1823
Sodium azide	TCI America	CAS 26628-22-8
Software and algorithms
EPU	Thermo Scientific	Part # 1025080
Relion 3.0	Zivanov et al.2	https://www3.mrc-lmb.cam.ac.uk/relion/index.php/Main_Page
UCSF Chimera	Pettersen et al.3	Cgl.ucsf.edu/chimera/
Leginon	Suloway et al.4	PMID: 15890530
Appion	Lander et al.5	https://emg.nysbc.org/redmine/projects/appion
DoG Picker	Voss et al.6	https://emg.nysbc.org/redmine/projects/appion
Other
AKTA Pure 25 M1	GE, Cytiva	N/A
Superdex 200 increase 10/300	Cytiva	289990944
Talos F200C TEM	Thermo Scientific	N/A
CETA 16M camera 200 kV	Thermo Scientific	N/A
Nanodrop 2000	Thermo Scientific	Cat # ND2000
Electron microscopy copper mesh grids	Electron Microscopy Sciences	Cat # EMS400-Cu
Pelco easiGlow Glow Discharge Cleaning System	Ted Pella Inc.	921000
0.22 μm pore filter	Cytiva	6780-2502
30 kDa 15 mL concentrator	Milipore	REF UFC803096
Sterile collodion 2% amyl acetate	Electron Microscopy Sciences	Cat # 12620-50
Graphite Rods	Ted Pella Inc.	Cat # 61-35
Cressington Carbon evaporator	Ted Pella Inc.	Model # 9620
Parafilm “M”	Bemis	PM-996
Filter paper 1	Whatman	Cat # 1001 090