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Titolo:
Transmembrane alpha-helices in the gap junction membrane channel: Systematic search of packing models based on the pair potential function
Autore:
Nunn, RS; Macke, TJ; Olson, AJ; Yeager, M;
Indirizzi:
Scripps Res Inst, Dept Cell Biol, La Jolla, CA 92037 USA Scripps Res InstLa Jolla CA USA 92037 Cell Biol, La Jolla, CA 92037 USA Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA Scripps Res Inst La Jolla CA USA 92037 t Mol Biol, La Jolla, CA 92037 USA Scripps Clin, Div Cardiovasc Dis, La Jolla, CA 92037 USA Scripps Clin La Jolla CA USA 92037 Cardiovasc Dis, La Jolla, CA 92037 USA
Titolo Testata:
MICROSCOPY RESEARCH AND TECHNIQUE
fascicolo: 3, volume: 52, anno: 2001,
pagine: 344 - 351
SICI:
1059-910X(20010201)52:3<344:TAITGJ>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTEIN ELECTRON CRYSTALLOGRAPHY; 3-DIMENSIONAL STRUCTURE; FOLD RECOGNITION; RESOLUTION; TOPOLOGY; DENSITY; VISUALIZATION; PREDICTION; COMPLEX;
Keywords:
alpha-helix; protein modeling; electron cryo-microscopy; gap junctions; connexins;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Yeager, M Scripps Res Inst, Dept Cell Biol, 10550 N Torrey Pines Rd, La Jolla, CA 92037 USA Scripps Res Inst 10550 N Torrey Pines Rd La Jolla CA USA 92037 A
Citazione:
R.S. Nunn et al., "Transmembrane alpha-helices in the gap junction membrane channel: Systematic search of packing models based on the pair potential function", MICROSC RES, 52(3), 2001, pp. 344-351

Abstract

Recent progress in the field of electron cryo-microscopy and image analysts has shown that there is an overwhelming need to interpret medium resolution (5 to 10 Angstrom) three-dimensional maps. Traditional methods of fitting amino acid residues into electron density using molecular modeling programs must be supplemented with further analysis. We have used a potential of mean force (PMF) method, derived from Boltzmann statistics in protein structure, to generate models for the packing of oc-helices, using pairwise potentials between amino acid residues. The approach was tested using the three-dimensional map of a recombinant cardiac gap junction membrane channel provided by electron cryo-crystallography (Unger et al., 1997; 1999a, 1999b) which had a resolution of 7.5 Angstrom in the membrane plane and 21 Angstromin the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which was consistent with an or-helical conformation for the four transmembrane domains of each connexin subunit. Based on the three-dimensional map and the amino acid sequence for the 4 transmembranedomains determined by hydropathy analysis, we used the modeling utility SymServ (Macke et al., 1998) to build hexameric connexons with 24 transmembrane a-helices. Canonical cc-helices were aligned to the axes of the rods of density and translated along the density so that the center of masses coincided. The PMF function was used to evaluate 162,000 conformations for each of the 24 possible or-helical packing models. Since the different packing models yielded different energy distributions, the pair potential function appears to be a promising tool for evaluating the packing of oc-helices in membrane proteins. The analysis will be refined by energy calculations basedon the expectations that the outer boundary of the channel will be formed by hydrophobic residues in contact with the lipids. Microsc. Res. Tech. 52:344-351, 2001. (C) 2001 Wiley-Liss. Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 19:11:23