Annotations: 1KKD

Solution structure of the calmodulin binding domain (CaMBD) of small conductance Ca2+-activated potassium channels (SK2)

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1kkda_	Membrane and cell surface proteins and peptides	Small-conductance potassium channel	Small-conductance potassium channel	Small-conductance potassium channel	Small-conductance potassium channel	Norway rat (Rattus norvegicus ) [TaxId: 10116 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2 Family	Small-conductance potassium channel gating domain	8025919	4001868	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Calmodulin binding domain (CaMBD)-like	8038298	3002034	SCOP2 (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	HD	e1kkdA1	A: beta barrels	X: ETN0001 domain-like	H: Rpp14/Pop5-like	T: Rpp14/Pop5-like	F: HD	ECOD (v294.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	1.10.287.70	Mainly Alpha	Orthogonal Bundle	Helix Hairpins		CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF02888	Calmodulin binding domain (CaMBD)	Calmodulin binding domain	Small-conductance Ca2+-activated K+ channels (SK channels) are independent of voltage and gated solely by intracellular Ca2+. These membrane channels are heteromeric complexes that comprise pore-forming alpha-subunits and the Ca2+-binding protein cal ...	Small-conductance Ca2+-activated K+ channels (SK channels) are independent of voltage and gated solely by intracellular Ca2+. These membrane channels are heteromeric complexes that comprise pore-forming alpha-subunits and the Ca2+-binding protein calmodulin (CaM) [1]. CaM binds to the SK channel through this the CaM-binding domain (CaMBD), which is located in an intracellular region of the alpha-subunit immediately carboxy-terminal to the pore. Channel opening is triggered when Ca2+ binds the EF hands in the N-lobe of CaM. The structure of this domain complexed with CaM is known [1]. This domain forms an elongated dimer with a CaM molecule bound at each end; each CaM wraps around three alpha-helices, two from one CaMBD subunit and one from the other.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	Small conductance calcium-activated potassium channel protein 2	protein binding binding protein domain specific binding cytoskeletal protein binding alpha-actinin binding actinin binding passive transmembrane transporter activity monoatomic ion channel activity channel activity monoatomic ion transmembrane transporter activity transporter activity transmembrane transporter activity monoatomic cation transmembrane transporter activity calcium-activated cation channel activity protein binding binding protein domain specific binding cytoskeletal protein binding alpha-actinin binding actinin binding passive transmembrane transporter activity monoatomic ion channel activity channel activity monoatomic ion transmembrane transporter activity transporter activity transmembrane transporter activity monoatomic cation transmembrane transporter activity calcium-activated cation channel activity gated channel activity potassium ion transmembrane transporter activity potassium channel activity monoatomic ion-gated channel activity calcium-activated potassium channel activity ligand-gated channel activity ligand-gated monoatomic ion channel activity monoatomic cation channel activity ligand-gated monoatomic cation channel activity metal ion transmembrane transporter activity small conductance calcium-activated potassium channel activity identical protein binding protein homodimerization activity protein dimerization activity calmodulin binding inward rectifier potassium channel activity voltage-gated channel activity voltage-gated monoatomic ion channel activity voltage-gated monoatomic cation channel activity voltage-gated potassium channel activity	transport monoatomic ion transmembrane transport potassium ion transmembrane transport establishment of localization metal ion transport monoatomic cation transmembrane transport transmembrane transport localization monoatomic ion transport potassium ion transport cellular process monoatomic cation transport cardiac muscle cell membrane repolarization heart process transport monoatomic ion transmembrane transport potassium ion transmembrane transport establishment of localization metal ion transport monoatomic cation transmembrane transport transmembrane transport localization monoatomic ion transport potassium ion transport cellular process monoatomic cation transport cardiac muscle cell membrane repolarization heart process multicellular organismal process system process cardiac muscle cell action potential involved in contraction membrane repolarization atrial cardiac muscle cell to AV node cell signaling regulation of heart contraction membrane repolarization during cardiac muscle cell action potential regulation of system process cardiac muscle contraction striated muscle contraction cell communication circulatory system process membrane repolarization during atrial cardiac muscle cell action potential actin filament-based process regulation of multicellular organismal process regulation of biological quality atrial cardiac muscle cell to AV node cell communication cell communication involved in cardiac conduction blood circulation cardiac muscle cell contraction regulation of biological process atrial cardiac muscle cell action potential biological regulation action potential actin filament-based movement muscle contraction muscle system process membrane repolarization during action potential regulation of blood circulation cardiac conduction atrial cardiac muscle cell membrane repolarization cardiac muscle cell action potential actin-mediated cell contraction heart contraction regulation of membrane potential trans-synaptic signaling regulation of signaling regulation of cellular process modulation of chemical synaptic transmission signaling cell-cell signaling chemical synaptic transmission synaptic signaling regulation of trans-synaptic signaling anterograde trans-synaptic signaling regulation of cell communication regulation of localization regulation of potassium ion transport regulation of transport regulation of monoatomic ion transport positive regulation of biological process positive regulation of potassium ion transport positive regulation of transport positive regulation of monoatomic ion transport regulation of metal ion transport regulation of neuronal synaptic plasticity regulation of synaptic plasticity regulation of monoatomic ion transmembrane transport regulation of potassium ion transmembrane transport regulation of transmembrane transport regulation of monoatomic cation transmembrane transport	cell periphery postsynapse cellular anatomical structure postsynaptic membrane synapse cell junction membrane plasma membrane plasma membrane region synaptic membrane sarcolemma T-tubule intracellular anatomical structure intracellular membraneless organelle cell periphery postsynapse cellular anatomical structure postsynaptic membrane synapse cell junction membrane plasma membrane plasma membrane region synaptic membrane sarcolemma T-tubule intracellular anatomical structure intracellular membraneless organelle Z disc sarcomere intracellular organelle I band organelle membraneless organelle contractile muscle fiber cytoplasm supramolecular fiber myofibril supramolecular polymer supramolecular complex cell surface membrane-bounded organelle endoplasmic reticulum smooth endoplasmic reticulum intracellular membrane-bounded organelle endomembrane system glutamatergic synapse neuron spine neuron projection dendritic spine plasma membrane bounded cell projection somatodendritic compartment cell projection dendrite dendritic tree cell body neuronal cell body

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR015449	Potassium channel, calcium-activated, SK	Family
A	IPR013099	Potassium channel domain	Domain
A	IPR036122	SK, calmodulin-binding domain superfamily	Homologous Superfamily
A	IPR004178	Calmodulin-binding domain	Domain

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RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.