Functional implications of modifying RyR-activating peptides for membrane permeability
| Autor: | Dulhunty, Angela F, Cengia, Louise, Young, Jacqui, Pace, Suzy M, Harvey, Peta J, Lamb, Graham D, Chan, Yiu-Ngok, Wimmer, Norbert, Toth, Istvan, Casarotto, Marco G |
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| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Cell Membrane Permeability
Lipid Bilayers Molecular Sequence Data Cell Culture Techniques Protein Structure Secondary Structure-Activity Relationship Caffeine Animals Humans Amino Acid Sequence Muscle Skeletal Nuclear Magnetic Resonance Biomolecular Alanine Binding Sites Dose-Response Relationship Drug Molecular Structure Myocardium Ryanodine Receptor Calcium Release Channel Stereoisomerism musculoskeletal system Peptide Fragments Electrophysiology Sarcoplasmic Reticulum Amino Acid Substitution Papers Calcium Rabbits Caco-2 Cells |
| Popis: | 1. Our aim was to determine whether lipoamino acid conjugation of peptides that are high-affinity activators of ryanodine receptor (RyR) channels would (a) render the peptides membrane permeable, (b) alter their structure or (a) reduce their activity. The peptides correspond to the A region of the II-III loop of the skeletal dihydropyridine receptor. 2. The lipoamino acid conjugation increased the apparent permeability of the peptide across the Caco-2 cell monolayer by up to approximately 20-fold. 3. Nuclear magnetic resonance showed that the alpha-helical structure of critical basic residues, required for optimal activation of RyRs, was retained after conjugation. 4. The conjugated peptides were more effective in enhancing resting Ca2+ release, Ca2+-induced Ca2+ release and caffeine-induced Ca2+ release from isolated sarcoplasmic reticulum (SR) than their unconjugated counterparts, and significantly enhanced caffeine-induced Ca2+ release from mechanically skinned extensor digitorum longus (EDL) fibres. 5. The effect of both conjugated and unconjugated peptides on Ca2+ release from skeletal SR was 30-fold greater than their effect on either cardiac Ca2+ release or on the Ca2+ Mg2+ ATPase. 6. A small and very low affinity effect of the peptide in slowing Ca2+ uptake by the Ca2+, Mg2+ ATPase was exacerbated by lipoamino acid conjugation in both isolated SR and in skinned EDL fibres. 7. The results show that lipoamino acid conjugation of A region peptides increases their membrane permeability without impairing their structure or efficacy in activating skeletal and cardiac RyRs. |
| Databáze: | OpenAIRE |
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