9SIX: CK1d

CK1d in complex with IG130. Determined by X-ray diffraction at 1.23 Å resolution. Released 9 Sept 2026.

Method: X-ray diffraction
Resolution: 1.23 Å
Organism: Homo sapiens
Chains: 2
Atoms: 5,670
Mol. weight: 70.09 kDa
Ligands: A1JOB, MLI
Released: 9 Sept 2026

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

Secondary structure: helices and β-sheets

9SIX contains 37 α-helices and 25 β-strands across 2 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: 18 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	9-18	10	1
β-strand	21-28	8	1
β-strand	33-41	9	1
α-helix	49-58	10
α-helix	65-67	3
β-strand	68-74	7	1
β-strand	77-83	7	1
β-strand	88	1	2
α-helix	89-95	7
α-helix	102-121	20
β-strand	124-125	2	3
α-helix	131-133	3
β-strand	134-136	3	2
α-helix	139-141	3
β-strand	145-147	3	2
β-strand	154-155	2	3
β-strand	157	1	4
α-helix	163	1
β-strand	164	1	4
α-helix	165-167	3
α-helix	177-179	3
α-helix	182-185	4
α-helix	188-190	3
α-helix	192-208	17
α-helix	221-233	13
α-helix	237-240	4
α-helix	246-257	12
α-helix	262-264	3
α-helix	266-279	14
α-helix	289-292	4

Chain B: 19 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	4-5	2	5
β-strand	9-17	9	5
β-strand	22-28	7	5
β-strand	33-41	9	5
α-helix	49-59	11
β-strand	68-74	7	5
β-strand	77-83	7	5
β-strand	88	1	6
α-helix	89-95	7
α-helix	102-121	20
β-strand	124-125	2	7
α-helix	131-133	3
β-strand	134-136	3	6
α-helix	137	1
α-helix	139-141	3
α-helix	144	1
β-strand	145-147	3	6
β-strand	154-155	2	7
β-strand	157	1	8
α-helix	163	1
β-strand	164	1	8
α-helix	165-167	3
α-helix	177-179	3
α-helix	182-185	4
α-helix	188-190	3
α-helix	192-208	17
α-helix	221-234	14
α-helix	237-240	4
α-helix	246-257	12
α-helix	262-264	3
α-helix	266-279	14
α-helix	289-291	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Casein kinase I isoform delta	A, B	protein	296	Homo sapiens	P48730 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>9SIX_1 Casein kinase I isoform delta (chains A, B)
SMMELRVGNRYRLGRKIGSGSFGDIYLGTDIAAGEEVAIKLECVKTKHPQLHIESKIYKM
MQGGVGIPTIRWCGAEGDYNVMVMELLGPSLEDLFNFCSRKFSLKTVLLLADQMISRIEY
IHSKNFIHRDVKPDNFLMGLGKKGNLVYIIDFGLAKKYRDARTHQHIPYRENKNLTGTAR
YASINTHLGIEQSRRDDLESLGYVLMYFNLGSLPWQGLKAATKRQKYERISEKKMSTPIE
VLCKGYPSEFATYLNFCRSLRFDDKPDYSYLRQLFRNLFHRQGFSYDYVFDWNMLK

Ligands and cofactors

ID	Name	Formula	Copies
A1JOB	6-(4-fluorophenyl)-3-(4-methylpiperazin-1-yl)-5-pyridin-4-yl-pyrazin-2-amine	C20 H21 F N6	2
MLI	Malonate ion	C3 H2 O4	2

Water and common crystallization additives (EDO) are not listed.

Primary citation

Crystal structures of CK1d with pyrazine inhibitors. Trevisan, L., Morasso, S., Dalle Vedove, A. et al. To be published.

Other PDB entries of the same protein (UniProt P48730 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6RCG 1.4 Å, Crystal structure of Casein kinase 1 delta (CK1 delta) complexed with SR3029 inhibitor
6RCH 1.45 Å, Crystal structure of Casein kinase I isoform delta (CK1 delta) complexed with SR4133…
8IZC 1.45 Å, Human CK1 Delta Kinase structure bound to Inhibitor
9SIV 1.5 Å, Phosphorylated CK1d in complex with IG84
9SIZ 1.5 Å, CK1d in complex with IG138
9SIW 1.55 Å, CK1d in complex with IG111
6PXN 1.55 Å, Human Casein Kinase 1 delta Tau mutant (R178C)
6GZM 1.59 Å, Crystal Structure of Human CKIdelta with A86
9SJ1 1.6 Å, CK1d in complex with IG84
8D7O 1.65 Å, Human Casein kinase 1 delta in complex with phosphorylated human PERIOD2 FASP peptide
8D7N 1.66 Å, Human Casein kinase 1 delta in complex with phosphorylated human PERIOD2 FASP peptide
4TWC 1.7 Å, 2-Benzamido-N-(1H-benzo[d]imidazol-2-yl)thiazole-4- carboxamide derivatives as potent…

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