12dk

structure of human KCNQ1-CaM-PIP2 intermediate state

Method: ELECTRON MICROSCOPY Dmax: 124.5 Å Quality: GOOD

1. Protein Identity and Related Structures Protein Identity & Related Structures

Potassium voltage-gated channel subfamily KQT member 1

Homo sapiens

UniProt P51787

State in the Current Structure

Assembly Oligomeric State Construct Mutations and Modifications Ligands, Ions and Associated Components Method and Experimental Conditions Structure Quality
1 Protein heterocomplex Heteromer Protein × 8 PDB declaration: octameric(8) Consistent with protein copy count Chain A; UniProt 76–620 Chain C; UniProt 76–620 Chain E; UniProt 76–620 Chain G; UniProt 76–620 Mutation:I145C, E160R, R231E Calmodulin-1 × 4 (P0DP23) PT5 [(2R)-1-octadecanoyloxy-3-[oxidanyl-[(1R,2R,3S,4R,5R,6S)-2,3,6-tris(oxidanyl)-4,5-diphosphonooxy-cyclohexyl]oxy-phospho ryl]oxy-propan-2-yl] (8Z)-icosa-5,8,11,14-tetraenoate × 4 CA CALCIUM ION × 8 ELECTRON MICROSCOPY cryo-EM buffer:pH 7.4 cryo-EM vitrification conditions:Cryogen ETHANE Resolution 3.47 Å

Other States of the Same Protein in the Database

Each row is a biological assembly of the same UniProt protein in another PDB entry. The “Difference from current entry” column identifies evidence-level differences; no tag means the currently parsed fields agree.

26 other PDB entries and 27 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence
UniProt name KCNQ1_HUMAN
Isoform
PDB entities 1
Chains and sequence ranges Author chain A; PDBConstruct 1–545; UniProt 76–620 Author chain C; PDBConstruct 1–545; UniProt 76–620 Author chain E; PDBConstruct 1–545; UniProt 76–620 Author chain G; PDBConstruct 1–545; UniProt 76–620

Calmodulin-1

Homo sapiens

UniProt P0DP23

State in the Current Structure

Assembly Oligomeric State Construct Mutations and Modifications Ligands, Ions and Associated Components Method and Experimental Conditions Structure Quality
1 Protein heterocomplex Heteromer Protein × 8 PDB declaration: octameric(8) Consistent with protein copy count Chain B; UniProt 1–149 Chain D; UniProt 1–149 Chain F; UniProt 1–149 Chain H; UniProt 1–149 Not recorded Potassium voltage-gated channel subfamily KQT member 1 × 4 (P51787) PT5 [(2R)-1-octadecanoyloxy-3-[oxidanyl-[(1R,2R,3S,4R,5R,6S)-2,3,6-tris(oxidanyl)-4,5-diphosphonooxy-cyclohexyl]oxy-phospho ryl]oxy-propan-2-yl] (8Z)-icosa-5,8,11,14-tetraenoate × 4 CA CALCIUM ION × 8 ELECTRON MICROSCOPY cryo-EM buffer:pH 7.4 cryo-EM vitrification conditions:Cryogen ETHANE Resolution 3.47 Å

Other States of the Same Protein in the Database

Each row is a biological assembly of the same UniProt protein in another PDB entry. The “Difference from current entry” column identifies evidence-level differences; no tag means the currently parsed fields agree.

213 other PDB entries and 279 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence
UniProt name CALM1_HUMAN
Isoform
PDB entities 2
Chains and sequence ranges Author chain B; PDBConstruct 1–149; UniProt 1–149 Author chain D; PDBConstruct 1–149; UniProt 1–149 Author chain F; PDBConstruct 1–149; UniProt 1–149 Author chain H; PDBConstruct 1–149; UniProt 1–149

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

SAXS scattering curve SAXS Profile

SAXS profile for 12dk

P(r) Distance Distribution P(r) Distribution

P(r) distribution for 12dk
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2. Structure Basics 2. Structure Basics

Entry ID entry_id12dk
Deposition date deposition_date2026-03-28
Structure title titlestructure of human KCNQ1-CaM-PIP2 intermediate state
Keywords keywordsKCNQ1, intermediate state, PIP2, MEMBRANE PROTEIN; MEMBRANE PROTEIN
Experimental Method methodELECTRON MICROSCOPY

3. SAXS Parameters (CRYSOL theoretical calculation) 3. SAXS Parameters (CRYSOL)

Radius of gyration Rg (Guinier) rg_guinier40.78
Radius of gyration Rg (electron density) rg_electron40.13
Forward intensity I(0) i0677182000.00
Molecular weight molecular_weight219790.0 kDa
Excluded volume excluded_volume277560 ų
Envelope volume envelope_volume393550 ų
Hydration-shell volume shell_volume77753 ų
Envelope diameter envelope_diameter129.1
Shell Rg shell_rg49.19
Envelope Rg envelope_rg39.39
Shape Rg shape_rg40.11
Total Rg total_rg40.68
Total atoms total_atoms15464
Residues n_residues1924
Spherical-harmonic order n_harmonics20
q range q_range— – 0.5000 −1
Data points n_points101
Shell type shell_typedirectional
Solvent electron density solvent_density0.3340 e/ų
Shell contrast contrast_shell0.0300 e/ų
CRYSOL version crysol_version4.1.3

4. P(r) Distance Distribution (GNOM inversion) 4. P(r) Analysis (GNOM)

Maximum dimension Dmax dmax124.5
Rg (real space) rg_real40.52
Rg uncertainty (real space) rg_real_error0.52
I(0) (real space) i0_real6.7720e+08
I(0) uncertainty (real space) i0_real_error9.1660e+06
Rg (reciprocal space) rg_reciprocal40.78
I(0) (reciprocal space) i0_reciprocal677400000.0000
Solution quality estimate total_estimate0.8931
Solution quality rating solution_quality GOOD a GOOD solution
P(r) peaks n_peaks2
Primary peak position r_peak_primary51.1
Skewness Skewness skewness0.036
Kurtosis Kurtosis kurtosis-0.508
Angular range angular_range— – 0.1950 −1
Current regularization parameter α current_alpha0.0000
Highest regularization parameter α highest_alpha58680000.0000
Real-space data points n_real_points40
GNOM version gnom_version4.1.3
Quality Criteria quality_criteria AN1: 0.000; Oscil: 0.904; Stabil: 1.000; Sysdev: 1.000; Positv: 1.000; Valcen: 0.960; Smooth: 0.934

5. Crystallography and Experiment 5. Crystallography & Experiment

6. Entities and Polymers Entities & Polymers (4)

8. Citations (1)

9. Files and Curves (10)