Conformation of human serum apolipoprotein A-I(166-185) in the presence of sodium dodecyl sulfate or dodecylphosphocholine by 1H-NMR and CD. Evidence for specific peptide-SDS interactions

Guangshun Wang, W. Dale Treleaven, Robert J. Cushley

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Abstract

The segment, YSDELRQRLAARLEALKENG, corresponding to residues 166 to 185 of human serum apolipoprotein A-I, was studied by circular dichroism and NMR spectroscopy in sodium dodecyl sulfate and dodecylphosphocholine micelles. 2-Dimensional NOESY, TOCSY and DQF-COSY spectra of apoA-I(166-185) in perdeuterated sodium dodecyl sulfate (SDS-d25) and dodecylphosphocholine (DPC-d38) micelles were collected at a peptide/SDS (DPC) ratio of 1:40. Similar CD spectra and NOE connectivity patterns were observed for apoA-I(166-185) in SDS and DPC, indicating a similar helical conformation in both. Conformations of apoA-I(166-185) in DPC-d38 micelles, and in SDS-d25 micelles at two pH values, 6.6 and 3.7, were determined using distance geometry calculations. Backbone superposition (N,C(α),C = O) for an ensemble of twenty-nine structures in DPC at pH 6.0 gave a RMSD of 0.45 ± 0.09 Å for the region D168 to K182, while for all atoms it was 1.60 ± 0.17 Å. In SDS, the ensemble of nineteen structures each at pH 6.6 and 3.7 gave RMSDs of 0.28 ± 0.07 Å and 0.35 ± 0.10 Å, respectively, for the region D168 to K182. RMSD for superposition of all atoms was 1.36 ± 0.10 Å and 1.38 ± 0.21 Å at the respective pH values. In all casts a highly defined class A amphipathic helical structure was found for the region R171 to K182. Since the same structure occurs in micelles with either negatively charged or zwitterionic head groups it strongly suggests a dominant role for hydrophobic interactions in stabilizing the complex. The Y166 aromatic ring is bent back upon the helix axis at the lower pH. NMR determination of pK(a) values for D168, E169, E179 and E183 in the presence of SDS or DPC indicated a micro-pH at the micellar surface approximately one pH unit higher than the normal residue pK(a). SDS interactions with the peptide were examined by collecting 1H NOESY spectra in the presence of protiated SDS. Residues R171, R173, R177, as well as the aromatic ring of Y166, were shown by intermolecular NOE measurements to interact with SDS, hence a key interaction in stabilizing the complex appears to be between interfacial basic side-chains and SDS alkyl chains.

Original languageEnglish (US)
Pages (from-to)174-184
Number of pages11
JournalBiochimica et Biophysica Acta - Lipids and Lipid Metabolism
Volume1301
Issue number3
DOIs
StatePublished - Jan 1 1996

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Apolipoprotein A-I
Micelles
Sodium Dodecyl Sulfate
Conformations
Nuclear magnetic resonance
Peptides
Serum
Circular dichroism spectroscopy
Atoms
Nuclear magnetic resonance spectroscopy
Circular Dichroism
dodecylphosphocholine
human APOA1 protein
Proton Magnetic Resonance Spectroscopy
Hydrophobic and Hydrophilic Interactions
Geometry
Magnetic Resonance Spectroscopy
Head

Keywords

  • Amphipathic helix
  • Convex constraint analysis
  • Distance geometry
  • HDL
  • NMR, 2-dimensional
  • pH effect

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

Cite this

@article{82eef299a81a4996803e37c5aa61255c,
title = "Conformation of human serum apolipoprotein A-I(166-185) in the presence of sodium dodecyl sulfate or dodecylphosphocholine by 1H-NMR and CD. Evidence for specific peptide-SDS interactions",
abstract = "The segment, YSDELRQRLAARLEALKENG, corresponding to residues 166 to 185 of human serum apolipoprotein A-I, was studied by circular dichroism and NMR spectroscopy in sodium dodecyl sulfate and dodecylphosphocholine micelles. 2-Dimensional NOESY, TOCSY and DQF-COSY spectra of apoA-I(166-185) in perdeuterated sodium dodecyl sulfate (SDS-d25) and dodecylphosphocholine (DPC-d38) micelles were collected at a peptide/SDS (DPC) ratio of 1:40. Similar CD spectra and NOE connectivity patterns were observed for apoA-I(166-185) in SDS and DPC, indicating a similar helical conformation in both. Conformations of apoA-I(166-185) in DPC-d38 micelles, and in SDS-d25 micelles at two pH values, 6.6 and 3.7, were determined using distance geometry calculations. Backbone superposition (N,C(α),C = O) for an ensemble of twenty-nine structures in DPC at pH 6.0 gave a RMSD of 0.45 ± 0.09 {\AA} for the region D168 to K182, while for all atoms it was 1.60 ± 0.17 {\AA}. In SDS, the ensemble of nineteen structures each at pH 6.6 and 3.7 gave RMSDs of 0.28 ± 0.07 {\AA} and 0.35 ± 0.10 {\AA}, respectively, for the region D168 to K182. RMSD for superposition of all atoms was 1.36 ± 0.10 {\AA} and 1.38 ± 0.21 {\AA} at the respective pH values. In all casts a highly defined class A amphipathic helical structure was found for the region R171 to K182. Since the same structure occurs in micelles with either negatively charged or zwitterionic head groups it strongly suggests a dominant role for hydrophobic interactions in stabilizing the complex. The Y166 aromatic ring is bent back upon the helix axis at the lower pH. NMR determination of pK(a) values for D168, E169, E179 and E183 in the presence of SDS or DPC indicated a micro-pH at the micellar surface approximately one pH unit higher than the normal residue pK(a). SDS interactions with the peptide were examined by collecting 1H NOESY spectra in the presence of protiated SDS. Residues R171, R173, R177, as well as the aromatic ring of Y166, were shown by intermolecular NOE measurements to interact with SDS, hence a key interaction in stabilizing the complex appears to be between interfacial basic side-chains and SDS alkyl chains.",
keywords = "Amphipathic helix, Convex constraint analysis, Distance geometry, HDL, NMR, 2-dimensional, pH effect",
author = "Guangshun Wang and Treleaven, {W. Dale} and Cushley, {Robert J.}",
year = "1996",
month = "1",
day = "1",
doi = "10.1016/0005-2760(96)00037-9",
language = "English (US)",
volume = "1301",
pages = "174--184",
journal = "Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids",
issn = "1388-1981",
publisher = "Elsevier",
number = "3",

}

TY - JOUR

T1 - Conformation of human serum apolipoprotein A-I(166-185) in the presence of sodium dodecyl sulfate or dodecylphosphocholine by 1H-NMR and CD. Evidence for specific peptide-SDS interactions

AU - Wang, Guangshun

AU - Treleaven, W. Dale

AU - Cushley, Robert J.

PY - 1996/1/1

Y1 - 1996/1/1

N2 - The segment, YSDELRQRLAARLEALKENG, corresponding to residues 166 to 185 of human serum apolipoprotein A-I, was studied by circular dichroism and NMR spectroscopy in sodium dodecyl sulfate and dodecylphosphocholine micelles. 2-Dimensional NOESY, TOCSY and DQF-COSY spectra of apoA-I(166-185) in perdeuterated sodium dodecyl sulfate (SDS-d25) and dodecylphosphocholine (DPC-d38) micelles were collected at a peptide/SDS (DPC) ratio of 1:40. Similar CD spectra and NOE connectivity patterns were observed for apoA-I(166-185) in SDS and DPC, indicating a similar helical conformation in both. Conformations of apoA-I(166-185) in DPC-d38 micelles, and in SDS-d25 micelles at two pH values, 6.6 and 3.7, were determined using distance geometry calculations. Backbone superposition (N,C(α),C = O) for an ensemble of twenty-nine structures in DPC at pH 6.0 gave a RMSD of 0.45 ± 0.09 Å for the region D168 to K182, while for all atoms it was 1.60 ± 0.17 Å. In SDS, the ensemble of nineteen structures each at pH 6.6 and 3.7 gave RMSDs of 0.28 ± 0.07 Å and 0.35 ± 0.10 Å, respectively, for the region D168 to K182. RMSD for superposition of all atoms was 1.36 ± 0.10 Å and 1.38 ± 0.21 Å at the respective pH values. In all casts a highly defined class A amphipathic helical structure was found for the region R171 to K182. Since the same structure occurs in micelles with either negatively charged or zwitterionic head groups it strongly suggests a dominant role for hydrophobic interactions in stabilizing the complex. The Y166 aromatic ring is bent back upon the helix axis at the lower pH. NMR determination of pK(a) values for D168, E169, E179 and E183 in the presence of SDS or DPC indicated a micro-pH at the micellar surface approximately one pH unit higher than the normal residue pK(a). SDS interactions with the peptide were examined by collecting 1H NOESY spectra in the presence of protiated SDS. Residues R171, R173, R177, as well as the aromatic ring of Y166, were shown by intermolecular NOE measurements to interact with SDS, hence a key interaction in stabilizing the complex appears to be between interfacial basic side-chains and SDS alkyl chains.

AB - The segment, YSDELRQRLAARLEALKENG, corresponding to residues 166 to 185 of human serum apolipoprotein A-I, was studied by circular dichroism and NMR spectroscopy in sodium dodecyl sulfate and dodecylphosphocholine micelles. 2-Dimensional NOESY, TOCSY and DQF-COSY spectra of apoA-I(166-185) in perdeuterated sodium dodecyl sulfate (SDS-d25) and dodecylphosphocholine (DPC-d38) micelles were collected at a peptide/SDS (DPC) ratio of 1:40. Similar CD spectra and NOE connectivity patterns were observed for apoA-I(166-185) in SDS and DPC, indicating a similar helical conformation in both. Conformations of apoA-I(166-185) in DPC-d38 micelles, and in SDS-d25 micelles at two pH values, 6.6 and 3.7, were determined using distance geometry calculations. Backbone superposition (N,C(α),C = O) for an ensemble of twenty-nine structures in DPC at pH 6.0 gave a RMSD of 0.45 ± 0.09 Å for the region D168 to K182, while for all atoms it was 1.60 ± 0.17 Å. In SDS, the ensemble of nineteen structures each at pH 6.6 and 3.7 gave RMSDs of 0.28 ± 0.07 Å and 0.35 ± 0.10 Å, respectively, for the region D168 to K182. RMSD for superposition of all atoms was 1.36 ± 0.10 Å and 1.38 ± 0.21 Å at the respective pH values. In all casts a highly defined class A amphipathic helical structure was found for the region R171 to K182. Since the same structure occurs in micelles with either negatively charged or zwitterionic head groups it strongly suggests a dominant role for hydrophobic interactions in stabilizing the complex. The Y166 aromatic ring is bent back upon the helix axis at the lower pH. NMR determination of pK(a) values for D168, E169, E179 and E183 in the presence of SDS or DPC indicated a micro-pH at the micellar surface approximately one pH unit higher than the normal residue pK(a). SDS interactions with the peptide were examined by collecting 1H NOESY spectra in the presence of protiated SDS. Residues R171, R173, R177, as well as the aromatic ring of Y166, were shown by intermolecular NOE measurements to interact with SDS, hence a key interaction in stabilizing the complex appears to be between interfacial basic side-chains and SDS alkyl chains.

KW - Amphipathic helix

KW - Convex constraint analysis

KW - Distance geometry

KW - HDL

KW - NMR, 2-dimensional

KW - pH effect

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U2 - 10.1016/0005-2760(96)00037-9

DO - 10.1016/0005-2760(96)00037-9

M3 - Article

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AN - SCOPUS:0029984176

VL - 1301

SP - 174

EP - 184

JO - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids

JF - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids

SN - 1388-1981

IS - 3

ER -