REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
APC Rat anti-Mouse IgG1	BD Biosciences	560089; RRID: AB_1645625
Anti-AID	Chaudhuri et al., 2003	N/A
Anti-GFP	MBL	Code # 598; RRID: AB_10597267
Anti-CD40	eBioscience	16-0402-86
Bacterial and Virus Strains
E.coli Bl21 (DE3)	Agilent Technologies	200131
E. coli KL16	Coli Genetic Stock Center	CGSC# 4245
E. coli BW310	Coli Genetic Stock Center	CGSC# 6078
GIBCO Sf9 cells	Thermo Scientific	11496-015
DH10Bac	Thermo Scientific	10361-012
Chemicals, Peptides, and Recombinant Proteins
SYBR Gold Nucleic Acid Gel Stain	Thermo Scientific	S-11494
40% Acrylamide/Bis Solution, 19:1	Bio-Rad	161-0144
SIGMAFAST Protease Inhibitor Cocktail Tablets, EDTA-Free	Sigma-Aldrich	S8830-20TAB
Rifampicin	Sigma-Aldrich	R3501-250MG
Dimethyl sulfate	Sigma-Aldrich	D186309-100ML
Piperidine	Sigma-Aldrich	411027-100ML
Cellfectin II Reagent	Invitrogen	Cat#10362-100
Recombinant Mouse Interleukin-4/IL-4	Novoprotein	Cat#CK15
Lipopolysaccharides from Escherichia coliO111:B4	Sigma Aldrich	L2630-100MG
Uracil-DNA Glycosylase	NEB	M0280S
2′-deoxycytidine	Sigma-Aldrich	D3897-500MG
2′-deoxycytidine 5′-monophosphate	Sigma-Aldrich	D7625-100MG
Cytidine	Sigma-Aldrich	C4654-1G
Cytidine 5′-monophosphate	Sigma-Aldrich	C1006-1G
Uranyl formate	Electron Microscopy Sciences	22450
PreScission protease	GE Healthcare	27-0843-01
LB Broth	RPI	L24066-5000.0
HyClone SFX-Insect Media	Thermo Scientific	SH30278LS
Grace’s Insect Medium, Supplemented	Thermo Scientific	11605-102
Fetal Bovine Serum	Sigma-Aldrich	TMS-013-B
Critical Commercial Assays
EasySep Mouse B Cell Isolation Kit	STEMCELL Technologies	Cat#19854
Deposited Data
AID.crystal, co-crystallized with G4 DNA	Protein Data Bank	PDB: 5W0Z
AID.crystal E58A, co-crystallized with Branched DNA and cacodylic acid	Protein Data Bank	PDB: 5W0R
AID.crystal E58A, co-crystallized with dsDNA and cytidine	Protein Data Bank	PDB: 5W1C
AID.crystal E58A, co-crystallized with dsDNA and dCMP	Protein Data Bank	PDB: 5W0U
Recombinant DNA
pGEX6P1	GE Healthcare	Cat#28954648
pTrc99A	DNA Resource Core	N/A
pFastBac	Thermo Scientific	10584-027
All synthesized DNA/RNA	Integrated DNA Technologies	N/A
Other
S1000 Thermal Cycler	Bio-Rad	S1000
ChemiDoc MP imager	Bio-Rad	1708280
Image Lab Version 4.1	Bio-Rad	N/A
Image Scanner FLA-9000	Fujifilm	N/A
Multi Gauge Version 3.0	Fujifilm	N/A
Origin	OriginLab Corporation	N/A
mini-DAWN TRISTAR	Wyatt Technology	N/A
Optilab DSP	Wyatt Technology	N/A
ASTRA V	Wyatt Technology	N/A
BLItz system with Streptavidin (SA) Biosensor	ForteBio	N/A
BLItz 1.1	ForteBio	N/A
Tecnai G2 Spirit BioTWIN electron microscope	FEI	N/A
J-815 CD Spectropolarimeter	Jasco	N/A
Phenix	Adams et al., 2010	N/A
CCP4	Winn et al., 2011	N/A
Coot	Emsley et al., 2010	N/A
Pymol	Schrödinger	N/A
POCASA 1.1	Yu et al., 2010	N/A
YASARA	YASARA Biosciences	N/A
Integrative Genomics Viewer	Broad Institute	N/A