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1l24
From Proteopedia
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[[Image:1l24.jpg|left|200px]] | [[Image:1l24.jpg|left|200px]] | ||
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'''ENHANCED PROTEIN THERMOSTABILITY FROM SITE-DIRECTED MUTATIONS THAT DECREASE THE ENTROPY OF UNFOLDING''' | '''ENHANCED PROTEIN THERMOSTABILITY FROM SITE-DIRECTED MUTATIONS THAT DECREASE THE ENTROPY OF UNFOLDING''' | ||
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[[Category: Matthews, B W.]] | [[Category: Matthews, B W.]] | ||
[[Category: Nicholson, H.]] | [[Category: Nicholson, H.]] | ||
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Revision as of 20:27, 2 May 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 Enterobacteria phage t4. 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 Fri May 2 23:27:12 2008
