Haloadaptation: insights from comparative modeling studies of halophilic archaeal DHFRs.
Proteins of halophilic archaea function in high-salt concentrations that inactivate or precipitate homologous proteins from non-halophilic species. Haloadaptation and the mechanism behind the phenomenon are not yet fully understood. In order to obtain useful information, homology modeling studies of dihydrofolate reductases (DHFRs) from halophilic archaea were performed that led to the construction of structural models. These models were subjected to energy minimization, structural evaluation and analysis. Complementary approaches concerning calculations of the amino acid composition and visual inspection of the surfaces and cores of the models, as well as calculations of electrostatic surface potentials, in comparison to non-halophilic DHFRs were also performed. The results provide evidence that sheds some light on the phenomenon of haloadaptation: DHFRs from halophilic archaea may maintain their fold, in high-salt concentrations, by sharing highly negatively charged surfaces and weak hydrophobic cores.
Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece.
Panagiotis L
PL
Kastritis
Nikos C
NC
Papandreou
Stavros J
SJ
Hamodrakas
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D019843:Archaeal Proteins / Q000737:chemistry; D006217:Halobacterium / Q000201:enzymology / Q000235:genetics; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000737:chemistry*; D055672:Static Electricity; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry* / Q000235:genetics
D000596:Amino Acids; D019843:Archaeal Proteins; D012965:Sodium Chloride; D013762:Tetrahydrofolate Dehydrogenase