9ydz

Cryo EM structure of KCa3.1_R355K_II/calmodulin channel in complex with rimtuzalcap

Method: ELECTRON MICROSCOPY Dmax: 129.2 Å Quality: GOOD

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

Intermediate conductance calcium-activated potassium channel protein 4

Homo sapiens

UniProt O15554

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 9–366 Chain B; UniProt 9–366 Chain C; UniProt 9–366 Chain D; UniProt 9–366 Mutation:R355K Calmodulin-1 × 4 (P0DP23) K POTASSIUM ION × 4 ELECTRON MICROSCOPY cryo-EM buffer:pH 8 cryo-EM vitrification conditions:Cryogen ETHANE Resolution 3.40 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.

16 other PDB entries and 17 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence
UniProt name KCNN4_HUMAN
Isoform
PDB entities 1
Chains and sequence ranges Author chain A; PDBConstruct 1–358; UniProt 9–366 Author chain B; PDBConstruct 1–358; UniProt 9–366 Author chain C; PDBConstruct 1–358; UniProt 9–366 Author chain D; PDBConstruct 1–358; UniProt 9–366

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 E; UniProt 82–148 Chain F; UniProt 82–148 Chain G; UniProt 82–148 Chain H; UniProt 82–148 Fragment:residues 82-148 Intermediate conductance calcium-activated potassium channel protein 4 × 4 (O15554) K POTASSIUM ION × 4 ELECTRON MICROSCOPY cryo-EM buffer:pH 8 cryo-EM vitrification conditions:Cryogen ETHANE Resolution 3.40 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 E; PDBConstruct 1–67; UniProt 82–148 Author chain F; PDBConstruct 1–67; UniProt 82–148 Author chain G; PDBConstruct 1–67; UniProt 82–148 Author chain H; PDBConstruct 1–67; UniProt 82–148

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 9ydz

P(r) Distance Distribution P(r) Distribution

P(r) distribution for 9ydz
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2. Structure Basics 2. Structure Basics

Entry ID entry_id9ydz
Deposition date deposition_date2025-09-23
Structure title titleCryo EM structure of KCa3.1_R355K_II/calmodulin channel in complex with rimtuzalcap
Keywords keywordsIon channel, Intermediate conductance calcium-activated potassium channel, Calmodulin binding protein, TRANSPORT PROTEIN; TRANSPORT PROTEIN
Experimental Method methodELECTRON MICROSCOPY

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

Radius of gyration Rg (Guinier) rg_guinier43.40
Radius of gyration Rg (electron density) rg_electron42.06
Forward intensity I(0) i0425564000.00
Molecular weight molecular_weight173570.0 kDa
Excluded volume excluded_volume219720 ų
Envelope volume envelope_volume346850 ų
Hydration-shell volume shell_volume68582 ų
Envelope diameter envelope_diameter129.0
Shell Rg shell_rg47.90
Envelope Rg envelope_rg40.80
Shape Rg shape_rg42.14
Total Rg total_rg42.12
Total atoms total_atoms12219
Residues n_residues1628
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 dmax129.2
Rg (real space) rg_real43.12
Rg uncertainty (real space) rg_real_error0.73
I(0) (real space) i0_real4.2560e+08
I(0) uncertainty (real space) i0_real_error6.5400e+06
Rg (reciprocal space) rg_reciprocal43.40
I(0) (reciprocal space) i0_reciprocal425700000.0000
Solution quality estimate total_estimate0.8799
Solution quality rating solution_quality GOOD a GOOD solution
P(r) peaks n_peaks1
Primary peak position r_peak_primary57.4
Skewness Skewness skewness0.038
Kurtosis Kurtosis kurtosis-0.484
Angular range angular_range— – 0.1800 −1
Current regularization parameter α current_alpha0.0000
Highest regularization parameter α highest_alpha33920000.0000
Real-space data points n_real_points37
GNOM version gnom_version4.1.3
Quality Criteria quality_criteria AN1: 0.000; Oscil: 0.929; Stabil: 1.000; Sysdev: 1.000; Positv: 1.000; Valcen: 0.966; Smooth: 0.682

5. Crystallography and Experiment 5. Crystallography & Experiment

6. Entities and Polymers Entities & Polymers (3)

8. Citations (1)

9. Files and Curves (10)