XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Lectures
EffECT of DOMaIN PEPTIDES OF THE carDIac ryaNODINE rECEPTOr
ON THE STaBILITY of BILAYER LIPID MEMBraNES
AND ON rYr2 ACTIVITY
Andrea Faltinová 1 , Jana Gaburjáková 1 , Ľubica Urbániková 2 , Matúš Hajduk 2 ,
Nataša Tomášková 3 , Marián Antalík 3 and Alexandra Zahradníková 1
1
Institute of Molecular Physiology and Genetics SAS, Bratislava, Slovakia,
2
Institute of Molecular Biology SAS, Bratislava, Slovakia,
3
Institute of Experimental Physics SAS, Košice, Slovakia
The cardiac ryanodine receptor (RyR2) contains one N-terminal, one central and two
C-terminal domains where mutations related to the cardiac arrhythmia, CPVT, tend to be
clustered. It is assumed that interaction between the N-terminal and the central domain
plays a role in forming the “domain switch” that regulates the stability of the resting
(closed) state of the RyR2. The aim of our study was to test whether mutation-prone
regions of the RyR2 suppress the stability of the closed conformation.
We constructed two peptides, DPcpvtN2 and DPcpvtC, corresponding to the N-terminal
and central part of the RyR2 with the highest occurrence of CPVT mutations. We examined
their effect on the resting activity of the RyR2. DPcpvtC (20 – 30 M) moderately
increased the RyR2 open probability, in accordance with the hypothesis. However, before
an effect on the RyR2 activity could be observed, DPcpvtN2 interacted with the BLM. In
the concentration range of 0.5 – 2.0 M the peptide perforated the BLM regardless of
the presence of the RyR2. Secondary structure analysis of DPcpvtN2 using bioinformatics,
CD-spectroscopy and mapping on the known tertiary structure of the IP3R ligand-binding
domain that is homological with the distal part of the N-terminal domain has shown
a high incidence of αhelix (45 - 76 %) as well as ascending hydrophobicity gradient in
the DPcpvtN2. These properties might explain the observed effect of DPcpvtN2 on the
stability of BLM.
Supported by grants APVV-0139-06, APVV-0441-09, VEGA 02/0190/10 and by the European
Union Contract No. LSHM-CT-2005-018833/EUGeneHeart.
XXII. Biochemistry Congress, Martin
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