ISDA

Entry Detail

PDB ID:

6BUT

Keywords:

Title:

Solution structure of full-length apo mammalian calmodulin bound to the IQ motif of the human voltage-gated sodium channel NaV1.2

Biological Source:

Source Organism:

Homo sapiens

Host Organism:

Escherichia coli

PDB Version:

Deposition Date:

2017-12-11

Release Date:

2019-06-19

Method Details:

Experimental Method:

SOLUTION NMR

Conformers Calculated:

Conformers Submitted:

Selection Criteria:

structures with the lowest energy

Download Validation Report

Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Description:Calmodulin-1
Chain IDs:A
Chain Length:148
Number of Molecules:1
Biological Source:Homo sapiens

UniProt ID:P0DP23 Pfam ID:PF13499

Protein Blast

Polymer Type:polypeptide(L)
Description:Sodium channel protein type 2 subunit alpha
Chain IDs:B
Chain Length:31
Number of Molecules:1
Biological Source:Homo sapiens

UniProt ID:Q99250

Ligand Molecules

Primary Citation

Na V 1.2 EFL domain allosterically enhances Ca 2+ binding to sites I and II of WT and pathogenic calmodulin mutants bound to the channel CTD.

Mahling, R, Hovey, L, Isbell, H.M, Marx, D.C, Miller, M.S, Kilpatrick, A.M, Weaver, L.D, Yoder, J.B, Kim, E.H, Andresen, C.N.J, Li, S, Shea, M.A, Mahling, R, Kilpatrick, A.M, Shea, M.A.Show

Structure ? ? ? (2021)

PMID: 33770503 DOI: 10.1016/j.str.2021.03.002

Abstact

Neuronal voltage-gated sodium channel NaV1.2 C-terminal domain (CTD) binds calmodulin (CaM) constitutively at its IQ motif. A solution structure (6BUT) and other NMR evidence showed that the CaM N domain (CaMN) is structurally independent of the C-domain (CaMC) whether CaM is bound to the NaV1.2IQp (1,901-1,927) or NaV1.2CTD (1,777-1,937) with or without calcium. However, in the CaM + NaV1.2CTD complex, the Ca2+ affinity of CaMN was more favorable than in free CaM, while Ca2+ affinity for CaMC was weaker than in the CaM + NaV1.2IQp complex. The CTD EF-like (EFL) domain allosterically widened the energetic gap between CaM domains. Cardiomyopathy-associated CaM mutants (N53I(N54I), D95V(D96V), A102V(A103V), E104A(E105A), D129G(D130G), and F141L(F142L)) all bound the NaV1.2 IQ motif favorably under resting (apo) conditions and bound calcium normally at CaMN sites. However, only N53I and A102V bound calcium at CaMC sites at [Ca2+] < 100 μM. Thus, they are expected to respond like wild-type CaM to Ca2+ spikes in excitable cells.

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