Micelle-induced curvature in a water-insoluble HIV-1 Env peptide revealed by NMR dipolar coupling measurement in stretched polyacrylamide gel.
The structure of a water-insoluble fragment encompassing residues 282-304 of the HIV envelope protein gp41 is studied when solubilized by dihexanoyl phosphatidylcholine (DHPC) and by small bicelles, consisting of a 4:1 molar ratio of DHPC and dimyristoyl phosphatidylcholine (DMPC). Weak alignment with the magnetic field was accomplished in a stretched polyacrylamide gel, permitting measurement of one-bond (1)H-(15)N, (13)Ca-(13)C', and (13)C'-(15)N dipolar couplings, which formed the basis for determining the peptide structure. In both detergent systems, the peptide adopts an alpha-helical conformation from residue 4 through 18. In the presence of the DHPC micelles the helix is strongly curved towards the hydrophobic surface, whereas in the presence of bicelles a much weaker curvature in the opposite direction is observed.
Chou
James J
JJ
Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA.
Kaufman
Joshua D
JD
Stahl
Stephen J
SJ
Wingfield
Paul T
PT
Bax
Ad
A
D000180:Acrylic Resins / Q000737:chemistry; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D015700:HIV Envelope Protein gp41 / Q000737:chemistry*; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010742:Phospholipid Ethers / Q000737:chemistry*; D011487:Protein Conformation; D012995:Solubility; D014867:Water / Q000737:chemistry
C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D000180:Acrylic Resins; D015700:HIV Envelope Protein gp41; D008823:Micelles; D010742:Phospholipid Ethers; C016680:polyacrylamide gels; D014867:Water; D004134:Dimyristoylphosphatidylcholine