caa a22 4500 47584646X CHVBK 20180406123915.0 cr unu---uuuuu 170329e20000201xx s 000 0 eng 10.1007/PL00000688 doi (NATIONALLICENCE)springer-10.1007/PL00000688 Biomolecular stability and life at high temperatures [Elektronische Daten] [R. M. Daniel*, D. A. Cowan] Abstract.: It is not clear what the upper temperature limit forlife is, or what specific factors will set this limit, but it is generally assumed that the limit will be dictated by molecular instability. In this review, we examine the thermal stability of two key groups of biological molecules: the intracellular small molecules/metabolites and the major classes of macromolecules. Certain small molecules/metabolites are unstable in vitro at the growth temperatures of the hyperthermophiles in which they are found. This instability appears to be dealt with in vivo by a range of mechanisms including rapid turnover, metabolic channelling and local stabilisation. Evidence to date suggests that proteins have the potential to be stable at substantially higher temperatures than those known to support life, but evidence concerning degradative reactions above 100 °C is slight. DNA duplex stability is apparently achieved at high temperature by elevated salt concentrations, polyamines, cationic proteins, and supercoiling rather than manipulation of C-G ratios. RNA stability seems dependent upon covalent modification, although secondary structure is probably also critical. The diether-linked lipids, which make up the monolayer membrane of most organisms growing above 85 °C are chemically very stable and seem potentially capable of maintaining membrane integrity at much higher temperatures. However, the in vivo implications of the in vitro instability of biomolecules are difficult to assess, and in vivo data are rare. Birkhäuser Verlag Basel,, 2000 Key words. Archaea nationallicence biomolecules nationallicence DNA nationallicence enzymes nationallicence lipids nationallicence membranes nationallicence proteins nationallicence RNA nationallicence stability nationallicence thermophiles nationallicence thermostability nationallicence Daniel* R. M. Thermophile Research Unit, Department of Biological Sciences, School of Science, University of Waikato, Private Bag 3105, Hamilton (New Zealand), Fax +64 7 8384324, e-mail:r.daniel@waikato.ac.nz, NZ aut Cowan D. A. Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT (United Kingdom), GB aut https://doi.org/10.1007/PL00000688 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/PL00000688 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Daniel* R. M. Thermophile Research Unit, Department of Biological Sciences, School of Science, University of Waikato, Private Bag 3105, Hamilton (New Zealand), Fax +64 7 8384324, e-mail:r.daniel@waikato.ac.nz, NZ aut NATIONALLICENCE 700 1- Cowan D. A. Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT (United Kingdom), GB aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer