KEY RESOURCES TABLE

REAGENT or RESOURCE	SOURCE	IDENTIFIER
Bacterial and Virus Strains
E. coli BL21 (DE3) cells	Invitrogen	Cat. # C600003
Chemicals, Peptides, and Recombinant Proteins
Ampicillin	Fisher Scientific	Cat. # BP1760–5
Isopropyl β-D-Thiogalactoside (IPTG)	Sigma-Aldrich	Cat. # I6758
Thrombin from bovine plasma	Millipore	Cat. # T7201
SYPRO-Orange	Invitrogen	Cat. # S6651
Amylose resin	New England Biolabs	Cat. # E8021L
Ni-NTA resin	QIAGEN	Cat. # 30210
Superdex 75 Increase 10/300 GL	GE Healthcare	Cat. # 29148721
N-succinyl-Leu-Tyr-7-amido-4-methylcoumarin (sLY-AMC)	Cayman Chemical	Cat. # 10008120
Ac-Leu-Leu-Tyr-7-amino-4-trifluoromethylcoumarin (Ac-LLY-AFC)	Fisher Scientific	Cat. # MP3AFC11610
Trans-epoxysuccinyl-L-leucylamido-(4-guanidino)-butane (E64)	Sigma-Aldrich	Cat. # E3132
Human calpastatin B27 domain	Calbiochem	Cat. # 208902
ProPlex HT-96 Screen	Molecular Dimensions	Cat. # MD1–42
H-E(EDANS)-KIEIVRKKPIFKKATV-K(DABCYL)-OH	Biopeptek	Order #. BPT18360101–3
Deposited Data
hCAPN5-PC	This work	PDB: 6P3Q
rCAPN1-PC complexed with ZLAK-3001	Qian et al., 2008	PDB: 2R9C
rCAPN1-PC complexed with ZLAK-3002	Qian et al., 2008	PDB: 2R9F
rCAPN1-PC complexed with SNJ-1945	Cuerrier et al., 2006	PDB: 2G8J
rCAPN1-PC complexed with leupeptin	Moldoveanu et al., 2004a	PDB: 1TL9
rCAPN1-PC complexed with E64	Moldoveanu et al., 2004a	PDB: 1TLO
rCAPN1-PC complexed with SNJ-1715	Cuerrier et al., 2006	PDB: 2G8E
hCAPN1-PC	Davis et al., 2007	PDB: 2ARY
hCAPN1-PC complexed with ZLLYCH2F	Li et al., 2006	PDB: 1ZCM
hCAPN9-PC complexed with leupeptin	Davis et al., 2007	PDB: 2P0R
hCAPN9-PC	Davis et al., 2007	PDB: 1ZIV
rCAPN2-PC	Moldoveanu et al., 2004a	PDB: 1MDW
rCAPN2 complexed with calpastatin	Hanna et al., 2008	PDB: 3BOW
rCAPN2-PC complexed with calpastatin	Moldoveanu et al., 2004a	PDB: 3DF0
hCAPN3-PC complexed with leupeptin	Yeetal., 2018	PDB: 6BKJ
hCAPN3-PC complexed with E64	Yeetal., 2018	PDB: 6BJD
hCAPN3-PC C129S mutant	Yeetal., 2018	PDB: 6BDT
hCAPN3-PC C129A mutant	Yeetal., 2018	PDB: 6BGP
hCAPN8-PC	Davis et al., 2006	PDB: 2NQA
Recombinant DNA
pMAL-C5X-hCAPN5-PC	This work	N/A
pMAL-C5X-hCAPN5-PC mutants	This work	N/A
pMAL-C5X-rCAPN1/5-PCDC2-loop	This work	N/A
pMAL-C5X-rCAPN1/5-PCDC2-loop mutants	This work	N/A
Software and Algorithms
XDS	Kabsch, 2010	http://xds.mpimf-heidelberg.mpg.de/
PHASER	McCoy et al., 2007	http://www.ccp4.ac.uk/html/phaser.html
PHENIX	Adams et al., 2011	http://www.phenix-online.org/
REFMAC	Murshudov et al., 2011	http://www.ccp4.ac.uk/html/refmac5.html
COOT	Emsley and Cowtan, 2004	https://www2.mrc-lmb.cam.ac.uk/Personal/pemsley/coot/
SasTool	4–2 Beamline, SSRL	https://www-ssrl.slac.stanford.edu/smb-saxs/content/documentation/sastool
ATSAS	Konarev et al., 2006	https://www.embl-hamburg.de/biosaxs/software.html
ScAtter	SIBLYS Beamline, ALS	https://bl1231.als.lbl.gov/scatter/
CRYSOL	Svergun et al., 1995	https://www.embl-hamburg.de/biosaxs/crysol.html
DMAN	Wang et al., 2012	http://www.structuralchemistry.org/pcsb/dman.php
MODELLER	Webb and Sali, 2017	https://salilab.org/modeller/
PDB-REDO	Gore et al., 2017; Joosten et al., 2009	https://pdb-redo.eu/
PyMOL	Schrödinger, LLC	https://pymol.org/2/
HMMER 3.1	Finn et al., 2011	http://hmmer.org/
MAFFT v7	Katoh and Standley, 2013	https://mafft.cbrc.jp/alignment/software/
CD-HIT	Li and Godzik, 2006	http://weizhongli-lab.org/cd-hit/
MaxAlign 1.1	Gouveia-Oliveira et al., 2007	http://www.cbs.dtu.dk/services/MaxAlign/
FastTree 2	Price et al., 2010	http://www.microbesonline.org/fasttree/
Geneious Tree Builder	Geneious, LLC	https://www.geneious.com/
ConSurf	Armon et al., 2001; Ashkenazy et al., 2016	https://consurf.tau.ac.il/
MEGA7	Kumar et al., 2016	https://www.megasoftware.net/
EsPript	Patrice Gouet and Xavier Robert	http://espript.ibcp.fr/
GraphPad Prism	GraphPad Software, Inc.	https://www.graphpad.com/