PDBsum entry 4zw2

Metal transport

PDB id: 4zw2

Contents

Protein chains

319 a.a.

20 a.a.

Ligands

PGE ×2

Waters ×285

PDB id:

4zw2

Name:

Metal transport

Title:

Crystal structure of the mouse voltage gated calcium channel beta subunit isoform 1a in complex with alpha interaction domain peptide.

Structure:

Voltage-dependent l-type calcium channel subunit beta-1, voltage-dependent l-type calcium channel subunit beta-1. Chain: a. Fragment: unp residue 68-185, linker, 261-462. Synonym: cab1,calcium channel voltage-dependent subunit beta 1,cab1, calcium channel voltage-dependent subunit beta 1. Engineered: yes. Voltage-dependent l-type calcium channel subunit alpha-1s. Chain: b.

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: cacnb1, cacnlb1. Expressed in: escherichia coli. Expression_system_taxid: 511693. Synthetic: yes. Organism_taxid: 10090

Resolution:

1.86Å R-factor: 0.171 R-free: 0.207

Authors:

N.C.Norris,A.J.Oakley

Key ref:

N.C.Norris et al. (2017). Structural and biophysical analyses of the skeletal dihydropyridine receptor β subunit β_1areveal critical roles of domain interactions for stability. J Biol Chem, 292, 8401-8411. PubMed id: 28351836

Date:

19-May-15 Release date: 01-Jun-16

Protein chain

Q8R3Z5  (CACB1_MOUSE) -  Voltage-dependent L-type calcium channel subunit beta-1 from Mus musculus

Seq: 597 a.a.

Struc: 319 a.a.*

Protein chain

Q02789  (CAC1S_MOUSE) -  Voltage-dependent L-type calcium channel subunit alpha-1S from Mus musculus

Seq: 1852 a.a.

Struc: 19 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

J Biol Chem 292:8401-8411 (2017)

PubMed id: 28351836

Structural and biophysical analyses of the skeletal dihydropyridine receptor β subunit β_1areveal critical roles of domain interactions for stability.

N.C.Norris, S.Joseph, S.Aditya, Y.Karunasekara, P.G.Board, A.F.Dulhunty, A.J.Oakley, M.G.Casarotto.

ABSTRACT

Excitation-contraction (EC) coupling in skeletal muscle requires a physical interaction between the voltage-gated calcium channel dihydropyridine receptor (DHPR) and the ryanodine receptor Ca²⁺release channel. Although the exact molecular mechanism that initiates skeletal EC coupling is unresolved, it is clear that both the α₁and β subunits of DHPR are essential for this process. Here, we employed a series of techniques, including size-exclusion chromatography-multi-angle light scattering, differential scanning fluorimetry, and isothermal calorimetry, to characterize various biophysical properties of the skeletal DHPR β subunit β_1aRemoval of the intrinsically disordered N and C termini and the hook region of β_1aprevented oligomerization, allowing for its structural determination by X-ray crystallography. The structure had a topology similar to that of previously determined β isoforms, which consist of SH3 and guanylate kinase domains. However, transition melting temperatures derived from the differential scanning fluorimetry experiments indicated a significant difference in stability of ∼2-3 °C between the β_1aand β_2aconstructs, and the addition of the DHPR α_1sI-II loop (α-interaction domain) peptide stabilized both β isoforms by ∼6-8 °C. Similar to other β isoforms, β_1abound with nanomolar affinity to the α-interaction domain, but binding affinities were influenced by amino acid substitutions in the adjacent SH3 domain. These results suggest that intramolecular interactions between the SH3 and guanylate kinase domains play a role in the stability of β_1awhile also providing a conduit for allosteric signaling events.