This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1l24
From Proteopedia
(New page: 200px<br /><applet load="1l24" size="450" color="white" frame="true" align="right" spinBox="true" caption="1l24, resolution 1.7Å" /> '''ENHANCED PROTEIN THER...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1l24.jpg|left|200px]]<br /><applet load="1l24" size=" | + | [[Image:1l24.jpg|left|200px]]<br /><applet load="1l24" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1l24, resolution 1.7Å" /> | caption="1l24, resolution 1.7Å" /> | ||
'''ENHANCED PROTEIN THERMOSTABILITY FROM SITE-DIRECTED MUTATIONS THAT DECREASE THE ENTROPY OF UNFOLDING'''<br /> | '''ENHANCED PROTEIN THERMOSTABILITY FROM SITE-DIRECTED MUTATIONS THAT DECREASE THE ENTROPY OF UNFOLDING'''<br /> | ||
==Overview== | ==Overview== | ||
| - | It is proposed that the stability of a protein can be increased by | + | It is proposed that the stability of a protein can be increased by selected amino acid substitutions that decrease the configurational entropy of unfolding. Two such substitutions, one of the form Xaa----Pro and the other of the form Gly----Xaa, were constructed in bacteriophage T4 lysozyme at sites consistent with the known three-dimensional structure. Both substitutions stabilize the protein toward reversible and irreversible thermal denaturation at physiological pH. The substitutions have no effect on enzymatic activity. High-resolution crystallographic analysis of the proline-containing mutant protein (Ala-82----Pro) shows that its three-dimensional structure is essentially identical with the wild-type enzyme. The overall structure of the other mutant enzyme (Gly-77----Ala) is also very similar to wild-type lysozyme, although there are localized conformational adjustments in the vicinity of the altered amino acid. The combination of a number of such amino acid replacements, each of which is expected to contribute approximately 1 kcal/mol (1 cal = 4.184 J) to the free energy of folding, may provide a general strategy for substantial improvement in the stability of a protein. |
==About this Structure== | ==About this Structure== | ||
| - | 1L24 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http:// | + | 1L24 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1L24 OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Lysozyme]] | [[Category: Lysozyme]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Matthews, B | + | [[Category: Matthews, B W.]] |
[[Category: Nicholson, H.]] | [[Category: Nicholson, H.]] | ||
[[Category: hydrolase (o-glycosyl)]] | [[Category: hydrolase (o-glycosyl)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:40:24 2008'' |
Revision as of 11:40, 21 February 2008
|
ENHANCED PROTEIN THERMOSTABILITY FROM SITE-DIRECTED MUTATIONS THAT DECREASE THE ENTROPY OF UNFOLDING
Overview
It is proposed that the stability of a protein can be increased by selected amino acid substitutions that decrease the configurational entropy of unfolding. Two such substitutions, one of the form Xaa----Pro and the other of the form Gly----Xaa, were constructed in bacteriophage T4 lysozyme at sites consistent with the known three-dimensional structure. Both substitutions stabilize the protein toward reversible and irreversible thermal denaturation at physiological pH. The substitutions have no effect on enzymatic activity. High-resolution crystallographic analysis of the proline-containing mutant protein (Ala-82----Pro) shows that its three-dimensional structure is essentially identical with the wild-type enzyme. The overall structure of the other mutant enzyme (Gly-77----Ala) is also very similar to wild-type lysozyme, although there are localized conformational adjustments in the vicinity of the altered amino acid. The combination of a number of such amino acid replacements, each of which is expected to contribute approximately 1 kcal/mol (1 cal = 4.184 J) to the free energy of folding, may provide a general strategy for substantial improvement in the stability of a protein.
About this Structure
1L24 is a Single protein structure of sequence from Bacteriophage t4. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
Reference
Enhanced protein thermostability from site-directed mutations that decrease the entropy of unfolding., Matthews BW, Nicholson H, Becktel WJ, Proc Natl Acad Sci U S A. 1987 Oct;84(19):6663-7. PMID:3477797
Page seeded by OCA on Thu Feb 21 13:40:24 2008
