The predicted transmembrane fragment 17 of the human multidrug resistance protein 1 (MRP1) behaves as an interfacial helix in membrane mimics

Autor: Manuel Garrigos, Béatrice de Foresta, Nadège Jamin, Michel Vincent, Jacques Gallay
Přispěvatelé: Lentz, Celine, Protéines membranaires transductrices d'énergie (PMTE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2007
Předmět:
Steady-state and time-resolved fluorescence
Circular dichroism
[SDV.BBM.BS] Life Sciences [q-bio]/Biochemistry
Molecular Biology/Structural Biology [q-bio.BM]
Stereochemistry
Phosphorylcholine
Biophysics
ATP-binding cassette transporter
Peptide
Multidrug resistance
Biochemistry
Aromatic residues
Protein Structure
Secondary
Amino Acids
Aromatic
Biomimetics
Multidrug Resistance Protein 1
Humans
ATP Binding Cassette Transporter
Subfamily B
Member 1
Amino Acid Sequence
Protein secondary structure
Micelles
ComputingMilieux_MISCELLANEOUS
Brominated detergents
chemistry.chemical_classification
[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Structural Biology [q-bio.BM]
Chemistry
Circular Dichroism
Membrane Proteins
Cell Biology
MRP1 (ABCC1) transmembrane helix 17
Peptide Fragments
Transmembrane protein
Molecular Weight
Transmembrane domain
Spectrometry
Fluorescence
Solubility
Mutation
Helix
Dodecylmaltoside and dodecylphosphocholine micelles
Zdroj: Biochimica et Biophysica Acta:Biomembranes
Biochimica et Biophysica Acta:Biomembranes, 2007, pp.538-552
ISSN: 0005-2736
1879-2642
DOI: 10.1016/j.bbamem.2006.11.021
Popis: The human multidrug resistance protein MRP1 (or ABCC1) is one of the most important members of the large ABC transporter family, in terms of both its biological (tissue defense) and pharmacological functions. Many studies have investigated the function of MRP1, but structural data remain scarce for this protein. We investigated the structure and dynamics of predicted transmembrane fragment 17 (TM17, from Ala(1227) to Ser(1251)), which contains a single Trp residue (W(1246)) involved in MRP1 substrate specificity and transport function. We synthesized TM17 and a modified peptide in which Ala(1227) was replaced by a charged Lys residue. Both peptides were readily solubilized in dodecylmaltoside (DM) or dodecylphosphocholine (DPC) micelles, as membrane mimics. The interaction of these peptides with DM or DPC micelles was studied by steady-state and time-resolved Trp fluorescence spectroscopy, including experiments in which Trp was quenched by acrylamide or by two brominated analogs of DM. The secondary structure of these peptides was determined by circular dichroism. Overall, the results obtained indicated significant structuring ( approximately 50% alpha-helix) of TM17 in the presence of either DM or DPC micelles as compared to buffer. A main interfacial location of TM17 is proposed, based on significant accessibility of Trp(1246) to brominated alkyl chains of DM and/or acrylamide. The comparison of various fluorescence parameters including lambda(max), lifetime distributions and Trp rotational mobility with those determined for model fluorescent transmembrane helices in the same detergents is also consistent with the interfacial location of TM17. We therefore suggest that TM17 intrinsic properties may be insufficient for its transmembrane insertion as proposed by the MRP1 consensus topological model. This insertion may also be controlled by additional constraints such as interactions with other TM domains and its position in the protein sequence. The particular pattern of behavior of this predicted transmembrane peptide may be the hallmark of a fragment involved in substrate transport.
Databáze: OpenAIRE
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