1l80: Difference between revisions

Revision as of 14:42, 21 February 2008

DESIGN AND STRUCTURAL ANALYSIS OF ALTERNATIVE HYDROPHOBIC CORE PACKING ARRANGEMENTS IN BACTERIOPHAGE T4 LYSOZYME

OverviewOverview

An attempt has been made to design modified core-packing arrangements in bacteriophage T4 lysozyme. Alternative replacements of the buried residues Leu99, Met102, Val111 and Phe153 were selected using packing calculations and energy minimization. To test the design procedure, a series of multiple mutants was constructed culminating in the replacement L99F/M102L/V111I/F153L. These variants decrease the stability of T4 lysozyme by approximately 0 to 2 kcal/mol. The crystal structures of a number of the variants were determined. In the variant in which Val111 was replaced by Ile, alpha-helix 107-114 moved by approximately 1.5 A, breaking the hydrogen bond between the backbone carbonyl group of Thr109 and the backbone amide group of Gly113. This conformational change was not anticipated by the design procedure. Compensating interactions of magnitude up to 1.1 kcal/mol occur for some sets of mutations, while other sets display nearly additive stability changes. Within experimental error, the stability of the double mutant V111F/F153L is additive, with delta delta G different by only 0.1 kcal/mol from the sum of the two single mutants. The quadruple mutant L99F/M102L/V111I/F153L is destabilized by 0.5 kcal/mol, compared to delta delta G = -1.6 kcal/mol for the sum of the four single mutants. Multiple mutants show smaller overall structural changes from wild-type than M102L or V111I alone. Co-operative changes in structure and stability can be rationalized in terms of specific structural differences between single and multiple mutants. Genuine repacking of the hydrophobic core of T4 lysozyme with minimal effects on structure, stability and activity thus appears to have been achieved.

About this StructureAbout this Structure

1L80 is a Single protein structure of sequence from Enterobacteria phage t2 with and as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.

ReferenceReference

Design and structural analysis of alternative hydrophobic core packing arrangements in bacteriophage T4 lysozyme., Hurley JH, Baase WA, Matthews BW, J Mol Biol. 1992 Apr 20;224(4):1143-59. PMID:1569571

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-[[Image:1l80.jpg|left|200px]]<br /><applet load="1l80" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1l80.jpg|left|200px]]<br /><applet load="1l80" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1l80, resolution 1.8&Aring;" />
 '''DESIGN AND STRUCTURAL ANALYSIS OF ALTERNATIVE HYDROPHOBIC CORE PACKING ARRANGEMENTS IN BACTERIOPHAGE T4 LYSOZYME'''<br />
 ==Overview==
-An attempt has been made to design modified core-packing arrangements in, bacteriophage T4 lysozyme. Alternative replacements of the buried residues, Leu99, Met102, Val111 and Phe153 were selected using packing calculations, and energy minimization. To test the design procedure, a series of, multiple mutants was constructed culminating in the replacement, L99F/M102L/V111I/F153L. These variants decrease the stability of T4, lysozyme by approximately 0 to 2 kcal/mol. The crystal structures of a, number of the variants were determined. In the variant in which Val111 was, replaced by Ile, alpha-helix 107-114 moved by approximately 1.5 A, breaking the hydrogen bond between the backbone carbonyl group of Thr109, and the backbone amide group of Gly113. This conformational change was not, anticipated by the design procedure. Compensating interactions of, magnitude up to 1.1 kcal/mol occur for some sets of mutations, while other, sets display nearly additive stability changes. Within experimental error, the stability of the double mutant V111F/F153L is additive, with delta, delta G different by only 0.1 kcal/mol from the sum of the two single, mutants. The quadruple mutant L99F/M102L/V111I/F153L is destabilized by, 0.5 kcal/mol, compared to delta delta G = -1.6 kcal/mol for the sum of the, four single mutants. Multiple mutants show smaller overall structural, changes from wild-type than M102L or V111I alone. Co-operative changes in, structure and stability can be rationalized in terms of specific, structural differences between single and multiple mutants. Genuine, repacking of the hydrophobic core of T4 lysozyme with minimal effects on, structure, stability and activity thus appears to have been achieved.
+An attempt has been made to design modified core-packing arrangements in bacteriophage T4 lysozyme. Alternative replacements of the buried residues Leu99, Met102, Val111 and Phe153 were selected using packing calculations and energy minimization. To test the design procedure, a series of multiple mutants was constructed culminating in the replacement L99F/M102L/V111I/F153L. These variants decrease the stability of T4 lysozyme by approximately 0 to 2 kcal/mol. The crystal structures of a number of the variants were determined. In the variant in which Val111 was replaced by Ile, alpha-helix 107-114 moved by approximately 1.5 A, breaking the hydrogen bond between the backbone carbonyl group of Thr109 and the backbone amide group of Gly113. This conformational change was not anticipated by the design procedure. Compensating interactions of magnitude up to 1.1 kcal/mol occur for some sets of mutations, while other sets display nearly additive stability changes. Within experimental error, the stability of the double mutant V111F/F153L is additive, with delta delta G different by only 0.1 kcal/mol from the sum of the two single mutants. The quadruple mutant L99F/M102L/V111I/F153L is destabilized by 0.5 kcal/mol, compared to delta delta G = -1.6 kcal/mol for the sum of the four single mutants. Multiple mutants show smaller overall structural changes from wild-type than M102L or V111I alone. Co-operative changes in structure and stability can be rationalized in terms of specific structural differences between single and multiple mutants. Genuine repacking of the hydrophobic core of T4 lysozyme with minimal effects on structure, stability and activity thus appears to have been achieved.
 ==About this Structure==
-L80 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Enterobacteria_phage_t2 Enterobacteria phage t2] with CL and BME as [http://en.wikipedia.org/wiki/ligands ligands]. 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://ispc.weizmann.ac.il/oca-bin/ocashort?id=1L80 OCA].
+L80 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Enterobacteria_phage_t2 Enterobacteria phage t2] with <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=BME:'>BME</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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=1L80 OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Lysozyme]]
 [[Category: Single protein]]
-[[Category: Hurley, J.H.]]
+[[Category: Hurley, J H.]]
-[[Category: Matthews, B.W.]]
+[[Category: Matthews, B W.]]
 [[Category: BME]]
 [[Category: CL]]
 [[Category: hydrolase (o-glycosyl)]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 20:21:26 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:42:16 2008''