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Structural insights into the human RyR2 N-terminal region involved in cardiac arrhythmias.

Borko L, Bauerová-Hlinková V, Hostinová E, Gašperík J, Beck K, Lai FA, Zahradníková A, Sevčík J - Acta Crystallogr. D Biol. Crystallogr. (2014)

Bottom Line: The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts.In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure.Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia.

ABSTRACT
Human ryanodine receptor 2 (hRyR2) mediates calcium release from the sarcoplasmic reticulum, enabling cardiomyocyte contraction. The N-terminal region of hRyR2 (amino acids 1-606) is the target of >30 arrhythmogenic mutations and contains a binding site for phosphoprotein phosphatase 1. Here, the solution and crystal structures determined under near-physiological conditions, as well as a homology model of the hRyR2 N-terminal region, are presented. The N-terminus is held together by a unique network of interactions among its three domains, A, B and C, in which the central helix (amino acids 410-437) plays a prominent stabilizing role. Importantly, the anion-binding site reported for the mouse RyR2 N-terminal region is notably absent from the human RyR2. The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts. In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure. Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.

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Temperature factors of Cα atoms as a function of residue number. The secondary-structure elements are shown as rectangles (blue, β-sheet; red, α-helix). The central α-helix is shown in purple. The gaps represent residues that are missing in the structure. Domains are indicated by double arrows (A, blue; B, green; C, red).
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fig1: Temperature factors of Cα atoms as a function of residue number. The secondary-structure elements are shown as rectangles (blue, β-sheet; red, α-helix). The central α-helix is shown in purple. The gaps represent residues that are missing in the structure. Domains are indicated by double arrows (A, blue; B, green; C, red).

Mentions: Crystal structure refinement (Table 1 ▶) converged with R and Rfree of 22.4 and 26.1%, respectively. The refined model had good geometry with r.m.s.d.s from ideal bond lengths and angles of 0.008 Å and 1.180°, respectively. The estimated overall coordinate error based on maximum likelihood (ESU) was 0.205 Å. The Ramachandran diagram (RAMPAGE; Lovell et al., 2003 ▶) showed that 99.2% of residues were in the allowed regions (Table 1 ▶). The average B factor for main-chain atoms and for all atoms was 36.9 and 37.7 Å2, respectively. The Wilson plot B factor was 50.4 Å2. The bar diagram (Fig. 1 ▶) shows the temperature factors for Cα atoms as a function of residue number. The average B factor for main-chain atoms and for all atoms was 36.9 and 37.9 Å2, respectively. The Wilson plot B factor was 50.4 Å2.


Structural insights into the human RyR2 N-terminal region involved in cardiac arrhythmias.

Borko L, Bauerová-Hlinková V, Hostinová E, Gašperík J, Beck K, Lai FA, Zahradníková A, Sevčík J - Acta Crystallogr. D Biol. Crystallogr. (2014)

Temperature factors of Cα atoms as a function of residue number. The secondary-structure elements are shown as rectangles (blue, β-sheet; red, α-helix). The central α-helix is shown in purple. The gaps represent residues that are missing in the structure. Domains are indicated by double arrows (A, blue; B, green; C, red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4220973&req=5

fig1: Temperature factors of Cα atoms as a function of residue number. The secondary-structure elements are shown as rectangles (blue, β-sheet; red, α-helix). The central α-helix is shown in purple. The gaps represent residues that are missing in the structure. Domains are indicated by double arrows (A, blue; B, green; C, red).
Mentions: Crystal structure refinement (Table 1 ▶) converged with R and Rfree of 22.4 and 26.1%, respectively. The refined model had good geometry with r.m.s.d.s from ideal bond lengths and angles of 0.008 Å and 1.180°, respectively. The estimated overall coordinate error based on maximum likelihood (ESU) was 0.205 Å. The Ramachandran diagram (RAMPAGE; Lovell et al., 2003 ▶) showed that 99.2% of residues were in the allowed regions (Table 1 ▶). The average B factor for main-chain atoms and for all atoms was 36.9 and 37.7 Å2, respectively. The Wilson plot B factor was 50.4 Å2. The bar diagram (Fig. 1 ▶) shows the temperature factors for Cα atoms as a function of residue number. The average B factor for main-chain atoms and for all atoms was 36.9 and 37.9 Å2, respectively. The Wilson plot B factor was 50.4 Å2.

Bottom Line: The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts.In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure.Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia.

ABSTRACT
Human ryanodine receptor 2 (hRyR2) mediates calcium release from the sarcoplasmic reticulum, enabling cardiomyocyte contraction. The N-terminal region of hRyR2 (amino acids 1-606) is the target of >30 arrhythmogenic mutations and contains a binding site for phosphoprotein phosphatase 1. Here, the solution and crystal structures determined under near-physiological conditions, as well as a homology model of the hRyR2 N-terminal region, are presented. The N-terminus is held together by a unique network of interactions among its three domains, A, B and C, in which the central helix (amino acids 410-437) plays a prominent stabilizing role. Importantly, the anion-binding site reported for the mouse RyR2 N-terminal region is notably absent from the human RyR2. The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts. In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure. Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.

Show MeSH
Related in: MedlinePlus