1l24
From Proteopedia
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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
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