KEY RESOURCE TABLE

REAGENT or RESOURCE	SOURCE	IDENTIFIER
Chemicals, Peptides, and Recombinant Proteins
Human DNA-PKcs (full-length)	This paper	Residues 1–4128
Human Ku70/80	This paper	Residues 1–609 and 1–732
Human Artemis	This paper	Residues 1–692
Deposited Data
DNA-PK-Artemis complex, cryoEM (3.0 Å)	This paper	PDB: 7SGL EMDB: EMD-25113
FATKIN domain of DNA-PK-Artemis (2.7 Å)	This paper	EMDB: EMD-25114
DNA-Artemis-Ku-N-heat of DNA-PK-Artemis (2.9 Å)	This paper	EMDB: EMD-25115
DNA-PK-DNA complex VII, cryoEM (3.3 Å)	This paper	PDB: 7SU3 EMDB: EMD-25439
DNA-PK-DNA complex VIII, cryoEM (3.6 Å)	This paper	PDB: 7SUD EMDB: EMD-25440
DNA-PK-DNA complex VIIa, cryoEM (4.2 Å)	This paper	EMDB: EMD-25112
DNA-PK-DNA complex VIIb, cryoEM (4.2 Å)	This paper	EMDB: EMD-25111
DNA-PK-DNA complex VIb, cryoEM (4.4 Å)	This paper	EMDB: EMD-25110
Original gel scans	Mendeley Data	http://dx.doi.org/10.17632/t3525wy6gk.1
Experimental Models: Cell Lines
HeLa-S3 cells	National Cell Culture Center	https://cellculturecompany.com/national-cell-culture-center/
HEK293T cells	ATCC	CRL-3216
DNA-PKcs deficient V3 cells	Katheryn Meek’s lab	N/A
Oligonucleotides
See DNA preparation in Table S2	This paper	N/A
Recombinant DNA
Ku70 in pLEXm plasmid	This paper	pWY2799
Ku80 in pLEXm plasmid	This paper	pWY2802
Artemis in pLEXm plasmid	This paper	pWY2332
Software and Algorithms
PyMol	Schrodinger	https://pymol.org/2/
Prism-8	GraphPad Software	https://www.graphpad.com/
CCP4	CCP4	http://www.ccp4.ac.uk
PHENIX	(Adams et al., 2010)	https://www.phenix-online.org
COOT	(Emsley, 2010)	https://www2.mrc-lmb.cam.ac.uk/personal/pemsley/coot/
UCSF Chimera	(Pettersen et al., 2004)	https://www.cgl.ucsf.edu/chimera/
cryoSPARC	(Punjani et al., 2017)	https://cryosparc.com/
RELION	(Scheres, 2012); (Fernandez-Leiro and Scheres, 2017)	https://www2.mrc-lmb.cam.ac.uk/relion
SerialEM	(Mastronarde, 2005)	https://bio3d.colorado.edu/SerialEM/