Table of Contents
Journal of Atomic, Molecular, and Optical Physics
Volume 2009, Article ID 638063, 9 pages
http://dx.doi.org/10.1155/2009/638063
Review Article

Fragility of Bioprotectant Glass-Forming Systems in Extremophiles

1Department of Physics, University of Messina, P.O. Box 55, Sperone 31, 98166 Messina, Italy
2Laboratoire de Dynamique et Structure des Matériaux Moléculaires, University of Lille 1, CNRS UMR 8024, 59655 Villeneuve d’Ascq Cedex, France

Received 25 January 2009; Revised 20 March 2009; Accepted 23 March 2009

Academic Editor: Derrick S. F. Crothers

Copyright © 2009 S. Magazù and F. Migliardo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A central issue in the adaptation of proteins and enzymes to extreme conditions is the conservation of their functional state, which is characterized by a well-balanced compromise of stability and flexibility. In this review work an overview of elastic neutron scattering (ENS) findings on a class of bioprotectant glass-forming systems, such as trehalose and its homologous (maltose and sucrose) water mixtures, is presented as a function of temperature and concentration. ENS, in fact, allows to determine some remarkable quantities in order to characterize the correlation among dynamical properties, the flexibility and fragility of biomolecules. The experimental results have pointed out a dynamical transition, which shows a crossover in molecular fluctuations between harmonic and anharmonic dynamical regimes. The ENS findings allow to characterize both the trehalose rigidity and flexibility, which are strictly connected to its superior bioprotective effectiveness. In this frame the lowest flexibility and fragility character of trehalose/ mixture with respect to maltose and sucrose/ mixtures indicate a better attitude to encapsulate biostructures in more rigid and temperature insensitive structures in approaching the glass transition.