Detail of "29557-51-5"

Reference

Interactions of the M2d segment of the acetylcholine receptor with lipid bilayers: A continuum-solvent model study

Interactions of the M2d segment of the acetylcholine receptor with lipid bilayers: A continuum-solvent model study. Kessel, Amit; Haliloglu, Turkan; Ben-tal, Nir (Department of Biochemistry, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel). Biophysical Journal, 85(6), 3687-3695 (English) 2003 Biophysical Society. CODEN: BIOJAU. ISSN: 0006-3495. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) M2d, one of the transmembrane segments of the nicotinic acetylcholine receptor, is a 23-amino-acid peptide, frequently used as a model for peptide-membrane interactions. In this and the companion article we describe studies of M2d-membrane interactions, using two different computational approaches. In the present work, we used continuum-solvent model calcns. to investigate key thermodn. aspects of its interactions with lipid bilayers. M2d was represented in at. detail and the bilayer was represented as a hydrophobic slab embedded in a structureless aq. phase. Our calcns. show that the transmembrane orientation is the most favorable orientation of the peptide in the bilayer, in good agreement with both exptl. and computational data. 29557-51-5 which is the cas registry number is also used here. Moreover, our calcns. produced the free energy of assocn. of M2d with the lipid bilayer, which, to our knowledge, has not been reported to date. The calcns. included 10 structures of M2d, detd. by NMR in dodecylphosphocholine micelles. All the structures were found to be stable inside the lipid bilayer, although their water-to-membrane transfer free energies differed by as much as 12 kT. Although most of the structures were roughly linear, a single structure had a kink in its central region. Interestingly, this structure was found to be the most stable inside the lipid bilayer, in agreement with mol. dynamics simulations of the peptide and with the recently detd. structure of the intact receptor. Our anal. showed that the kink reduced the polarity of the peptide in its central region by allowing the electrostatic masking of the Gln13 side chain in that area. Our calcns. also showed a tendency for the membrane to deform in response to peptide insertion, as has been previously found for the membrane-active peptides alamethicin and gramicidin. The results are compared to Monte Carlo simulations of the peptide-membrane system, as presented in the accompanying article. .

Peptide conformational changes induced by tryptophan-phosphocholine interactions in a micelle

Peptide conformational changes induced by tryptophan-phosphocholine interactions in a micelle. Neidigh, Jonathan W.; Andersen, Niels H. (Department of Chemistry, University of Washington, Seattle, WA 98195, USA). Biopolymers, 65(5), 354-361 (English) 2002 John Wiley & Sons, Inc. CODEN: BIPMAA. ISSN: 0006-3525. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) Sodium dodecylsulfate (SDS) and dodecylphosphocholine (DPC) micelles are often used to mimic the membrane- or receptor-bound states of peptides in NMR studies. From the present examn. of a 26-residue analog of exendin-4 (TrEX4) by NMR and CD in water, aq. 30% trifluoroethanol (TFE), and bound to both SDS and DPC micelles, it is clear that these two lipid micelles can yield very different peptide structures. The Trp-cage fold (also obsd. 29557-51-5 and 491588-84-2 which are cas registry numbers of chemicals are mentioned. in 30% TFE) is present when TrEX4 is bound to SDS micelles; however, tertiary structure is absent in the presence of DPC micelles. The loss of tertiary structure is attributed to an energetically favorable interaction (estd. as 2-3 kcal/mol) of the tryptophan side chain with the phosphocholine head groups. These dramatic structural differences suggest that care must be taken when using either SDS or DPC to mimic the membrane- or receptor-bound states. .