9R44: Human caspase-9 CARD

Crystal structure of human caspase-9 CARD. Determined by X-ray diffraction at 2.46 Å resolution. Released 20 May 2026.

Method: X-ray diffraction
Resolution: 2.46 Å
Organism: Homo sapiens
Chains: 4
Atoms: 3,430
Mol. weight: 48.54 kDa
Released: 20 May 2026

Explore 9R44 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9R44 contains 29 α-helices and 0 β-strands across 4 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 7 helices, 0 β-strands

Element	Residues	Length
α-helix	3-11	9
α-helix	13-19	7
α-helix	25-31	7
α-helix	37-44	8
α-helix	51-62	12
α-helix	69-79	11
α-helix	83-94	12

Chain E: 7 helices, 0 β-strands

Element	Residues	Length
α-helix	3-11	9
α-helix	13-19	7
α-helix	25-31	7
α-helix	37-44	8
α-helix	51-62	12
α-helix	69-78	10
α-helix	83-93	11

Chain H: 8 helices, 0 β-strands

Element	Residues	Length
α-helix	3-11	9
α-helix	13-19	7
α-helix	22-24	3
α-helix	26-31	6
α-helix	37-44	8
α-helix	51-62	12
α-helix	69-79	11
α-helix	83-93	11

Chain L: 7 helices, 0 β-strands

Element	Residues	Length
α-helix	3-11	9
α-helix	13-19	7
α-helix	25-31	7
α-helix	37-44	8
α-helix	51-62	12
α-helix	69-79	11
α-helix	83-98	16

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Caspase-9	A, E, H, L	protein	101	Homo sapiens	P55211 (AlphaFold model)

Sequence of entity 1 (A, E, H, L), FASTA

>9R44_1 Caspase-9 (chains A, E, H, L)
SGMDEADRRLLRRCRLRLVEELQVDQLWDALLSRELFRPHMIEDIQRAGSGSRRDQARQL
IIDLETRGSQALPLFISCLEDTGQDMLASFLRTNRQAAKLS

Primary citation

Mechanistic insights into the caspase-9 CARD oligomerization. Rawal, S., Bohn, S., Pavkov-Keller, T. et al. To be published.

Other PDB entries of the same protein (UniProt P55211 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3D9T 1.5 Å, CIAP1-BIR3 in complex with N-terminal peptide from Caspase-9 (ATPFQE)
4RHW 2.1 Å, Crystal structure of Apaf-1 CARD and caspase-9 CARD complex
1NW9 2.4 Å, Structure of caspase-9 in an inhibitory complex with xiap-BIR3
3YGS 2.5 Å, Apaf-1 card in complex with prodomain of procaspase-9
1JXQ 2.8 Å, Structure of cleaved, CARD domain deleted Caspase-9
2AR9 2.8 Å, Crystal structure of a dimeric caspase-9
5WVC 2.99 Å, Structure of the CARD-CARD disk
9S6F 3.3 Å, Cryo-EM structure of human caspase-9 CARD (WT) filament
3V3K 3.49 Å, Human caspase 9 in complex with bacterial effector protein
9S6E 3.5 Å, Cryo-EM structure of human caspase-9 CARD (H38R) mutant filament
5JUY 4.1 Å, Active human apoptosome with procaspase-9
5WVE 4.4 Å, Apaf-1-Caspase-9 holoenzyme

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