Foreword: Speaking Existence

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Folding of small disulfide-rich proteins : clarifying the puzzle

Premi a l'excel·lència investigadora. Àmbit de les Ciències Experimentals. 2008The process by which small proteins fold to their native conformations has been intensively studied over the last few decades. In this field, the particular chemistry of disulfide bond formation has facilitated the characterization of the oxidative folding of numerous small, disulfide-rich proteins with results that illustrate a high diversity of folding mechanisms, differing in the heterogeneity and disulfide pairing nativeness of their intermediates. In this review, we combine information on the folding of different protein models together with the recent structural determinations of major intermediates to provide new molecular clues in oxidative folding. Also, we turn to analyze the role of disulfide bonds in misfolding and protein aggregation and their implications in amyloidosis and conformational diseases

Localization Length Exponent in Quantum Percolation

Connecting perfect one-dimensional leads to sites i and j on the quantum percolation (QP) model, we calculate the transmission coefficient Tij(E) at an energy E near the band center and the averages of ΣijTij, Σijr2ijTij, and Σijr4ijTij to tenth order in the concentration p. In three dimensions, all three series diverge at pq=0.36+0.01−0.02, with exponents γ=0.82+0.10−0.15, γ+2ν, and γ+4ν. We find ν=0.38±0.07, differing from “usual” Anderson localization and violating the bound ν≥2/d of Chayes et al. [Phys. Rev. Lett. 57, 2999 (1986)]. Thus, QP belongs to a new universality class