Thermal adaptation

The number of thermally adaptive mutations resulting from directed evolution studies is too small at present to support a detailed statistical analysis. Here we summarize some properties of the mutations discovered in the studies reviewed above, and compare them to the amino-acid differences seen among naturally occurring enzymes that have adapted to different temperatures. Lists of the amino-acid substitutions discovered... 

It is not yet clear whether any rules for thermal adaptation are to be found in the qualitative features of the mutations discovered during directed evolution. The trends seen in Table V (preference for surface substitutions over buried substitutions, conservative over nonconservative, etc.) would most likely be seen in any pool of functional mutants selected from random mutant libraries. 

Although brains of differently thermally adapted species appear to contain similar numbers of LDH molecules, differently acclimated or acclimatized individuals of a species have been observed to alter the amounts of enzyme in their cells (Hazel and Prosser, 1974 Sidell, 1977). These temperature-compensatory adjustments in enzymatic activity typically entail altering concentrations of a given isoform of a protein, not the induction of a new isoform with different kinetic properties. That is, kcat does... 

Comparisons of Km values for orthologs of enzymes from differently thermally adapted... 

To summarize, studies of differently thermally adapted confamilial, congeneric, and con-specific organisms have shown that temperature differences of a few degrees Celsius have sufficient effects on proteins to favor adaptive change. Although studies to date have focused on only a few classes of proteins, the ubiquitous effects of temperature on protein conformation are such that many, and perhaps most, proteins are likely to exhibit a similar threshold for perturbation and adaptive change. 

Figure 7.9. Thermal stabilities of eye lens crystallins of differently thermally adapted vertebrates. The temperature (°C) at which 50% loss of secondary structure occurred, as measured using CD spectroscopy, is given as a function of the maximal body temperature of each species. Species (1) Pagothenia borchgrevinki (Antarctic fish), (2) Coryphaenoides armatus (deep-sea fish), (3) Coryphaen-oides rupestris (deep-sea fish),...

Above, we showed how a finely modulated balancing act between stabilizing and destabilizing forces yields marginally stable protein structures. We now examine in more detail how the same types of noncovalent interactions are used in differently thermally adapted proteins to achieve appropriate levels of structural stability. The adaptive changes discussed below are relevant to both global protein stability and to the establishment of the appropriate balance between stability and flexibility required for... 

Figure 7.27. The relationship between adaptation temperature and percentage of unsaturated acyl chains in synaptosomal phospholipids of differently thermally adapted vertebrates. Each symbol represents a different species. Open symbols denote phosphatidylethanolamine filled symbols denote phosphatidylcholine. (Figure modified after Logue et al., 2000.)...

Haney, P.J., J.H. Badger, G.L. Buldak, C.L Reich, C.R. Woese, and G.J. Olsen (1999). Thermal adaptation analyzed by comparison of protein sequences from mesophilic and extremely thermophilic Methanococcus species. Proc. Natl. Acad. Sci. USA. 96 3578-3583. 

Hazel, J.R. (1995). Thermal adaptation in biological membranes—is homeoviscous adaptation the explanation Annu. Rev. Physiol. 57 19 42. 

The resultant fabrics are unique in that they have many functional property improvements thermal adaptability due to the phase change nature of the bound polyol, durable press or resiliency, soil release, reduction of static charge, antimicrobial activity, enhanced hydrophilicity and improved flex life, and resistance to pilling. Because of the different molecular weights of polyols, resins, acid catalysts, and fabric constructions, there are numerous modified fabrics that can be produced with sets of improved attributes. Each fabric must be carefully evaluated for optimum curing conditions and formulations to produce the desired product. Several licenses have been granted for this process. Various types of apparel, healthcare items, and industrial fabrics are currently evaluated for commercial production [381,382]. 

Positive and Negative Design in Evolution and Thermal Adaptation of Natural Proteins... 

Berezovsky IN, Zeldovich KB, Shakhnovich EL Positive and negative design in stability and thermal adaptation of natural proteins. PLoS. Comput. Biol. 2007 3 e52. 

Zavodszky, P., Kardos, J., Svingor, A. and Petsko, G. (1998). Adjustment of conformational flexibility is a key event in the thermal adaptation of protein. Proc. Natl. Acad. Sci. USA 95, 7406-7411... 

Luo, M.Z. et al. 2005. Human Body s Thermal Adaptation and Thermal Comfort. Refrigeration and Air-Conditioning 1 75-78. 

No general strategy of thermal adaptation has yet been established. This holds for two reasons First, there is a hierarchical order of incremental contributions to... 

Boenigk, J., Jost, S., Stoeck, T., Garstecki, T. (2007). Differential thermal adaptation of clonal strains of a protist morphospecies originating from different climatic zones. Environmental Microbiology 9, 593-602. 

Actinobacteria (bacteria) F E Temperature 13000 Local thermal adaptation identical 16S sequences but some genetic variation at other loci Hahn and PockI (2005)... 

Spumella sp. (chrysophyte flagellate) F and T E Temperature (growth rate) 17000 Local thermal adaptation among strains Boenigk et al. (2007)... 

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