1a2q: Difference between revisions
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==Overview== | ==Overview== | ||
Six individual amino acid substitutions at separate positions in the, tertiary structure of subtilisin BPN' (EC 3.4.21.14) were found to, increase the stability of this enzyme, as judged by differential scanning, calorimetry and decreased rates of thermal inactivation. These stabilizing, changes, N218S, G169A, Y217K, M50F, Q206C, and N76D, were discovered, through the use of five different investigative approaches: (1) random, mutagenesis; (2) design of buried hydrophobic side groups; (3) design of, electrostatic interactions at Ca2+ binding sites; (4) sequence homology, consensus; and (5) serendipity. Individually, the six amino acid, substitutions increase the delta G of unfolding between 0.3 and 1.3, kcal/mol at 58.5 degrees C. The combination of these six individual, stabilizing ... | Six individual amino acid substitutions at separate positions in the, tertiary structure of subtilisin BPN' (EC 3.4.21.14) were found to, increase the stability of this enzyme, as judged by differential scanning, calorimetry and decreased rates of thermal inactivation. These stabilizing, changes, N218S, G169A, Y217K, M50F, Q206C, and N76D, were discovered, through the use of five different investigative approaches: (1) random, mutagenesis; (2) design of buried hydrophobic side groups; (3) design of, electrostatic interactions at Ca2+ binding sites; (4) sequence homology, consensus; and (5) serendipity. Individually, the six amino acid, substitutions increase the delta G of unfolding between 0.3 and 1.3, kcal/mol at 58.5 degrees C. The combination of these six individual, stabilizing mutations together into one subtilisin BPN' molecule was found, to result in approximately independent and additive increases in the delta, G of unfolding to give a net increase of 3.8 kcal/mol (58.5 degrees C)., Thermodynamic stability was also shown to be related to resistance to, irreversible inactivation, which included elevated temperatures (65, degrees C) or extreme alkalinity (pH 12.0). Under these denaturing, conditions, the rate of inactivation of the combination variant is, approximately 300 times slower than that of the wild-type subtilisin BPN'., A comparison of the 1.8-A-resolution crystal structures of mutant and, wild-type enzymes revealed only independent and localized structural, changes around the site of the amino acid side group, substitutions.(ABSTRACT TRUNCATED AT 250 WORDS) | ||
==About this Structure== | ==About this Structure== | ||
1A2Q is a | 1A2Q is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_amyloliquefaciens Bacillus amyloliquefaciens] with CA and ACN as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Subtilisin Subtilisin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.62 3.4.21.62] Structure known Active Sites: 169, 218, C22, C87, CA1 and CA2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1A2Q OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: sporulation]] | [[Category: sporulation]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:45:59 2007'' | ||
