Does the increased hydrophobicity of the interior and hydrophilicity of the exterior of an enzyme structure reflect its increased thermostability?
The values of hydrophobicity of internal and external elements of the secondary structure of three Bacillus alpha-amylase (beta alpha)8 barrel domains have been calculated in order to investigate whether there is some correlation between the values and the enzyme stability. All the values have been referred to the number of amino acids in the given beta-sheet or alpha-helix to eliminate the differences caused by non-equal length of the sheet or helix. Hydrophobicity units obtained have been averaged according to the number of internal (all beta-strands and helix alpha 7) and external (helices alpha 1-alpha 6 and alpha 8) elements of secondary structure of the alpha-amylase (beta alpha)8 barrel. The averaged hydrophobicity units have been found to correlate with the thermal stability of the three Bacillus alpha-amylases in terms of the increased hydrophobicity of the interior as well as the increased hydrophilicity of the exterior of the (beta alpha)8 barrel domain for the alpha-amylase with increased thermostability.
Janecek
S
S
Department of Biochemical Technology, Faculty of Chemical Technology, Slovak Technical University, Bratislava.
D001407:Bacillus / Q000201:enzymology*; D001412:Bacillus subtilis / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D006358:Hot Temperature; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D013045:Species Specificity; D000516:alpha-Amylases / Q000737:chemistry*
D001426:Bacterial Proteins; D000516:alpha-Amylases