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Medientyp:
E-Artikel
Titel:
Destruction of long-range interactions by a single mutation in lysozyme
Beteiligte:
Zhou, Ruhong;
Eleftheriou, Maria;
Royyuru, Ajay K.;
Berne, Bruce J.
Erschienen:
Proceedings of the National Academy of Sciences, 2007
Erschienen in:
Proceedings of the National Academy of Sciences, 104 (2007) 14, Seite 5824-5829
Sprache:
Englisch
DOI:
10.1073/pnas.0701249104
ISSN:
0027-8424;
1091-6490
Entstehung:
Anmerkungen:
Beschreibung:
We propose a mechanism, based on a ≥10-μs molecular dynamics simulation, for the surprising misfolding of hen egg-white lysozyme caused by a single mutation (W62G). Our simulations of the wild-type and mutant lysozymes in 8 M urea solution at biological temperature (with both pH 2 and 7) reveal that the mutant structure is much less stable than that of the wild type, with the mutant showing larger fluctuations and less native-like contacts. Analysis of local contacts reveals that the Trp-62 residue is the key to a cooperative long-range interaction within the wild type, where it acts like a bridge between two neighboring basic residues. Thus, a native-like cluster or nucleation site can form near these residues in the wild type but not in the mutant. The time evolution of the secondary structure also exhibits a quicker loss of the β-sheets in the mutant than in the wild type, whereas some of the α-helices persist during the entire simulation in both the wild type and the mutant in 8 M urea (even though the tertiary structures are basically all gone). These findings, while supporting the general conclusions of a recent experimental study by Dobson and coworkers [Klein-Seetharam J, Oikama M, Grimshaw SB, Wirmer J, Duchardt E, Ueda T, Imoto T, Smith LJ, Dobson CM, Schwalbe H (2002) Science 295:1719–1722], provide a detailed but different molecular picture of the misfolding mechanism.