262l: Difference between revisions
New page: left|200px<br /><applet load="262l" size="450" color="white" frame="true" align="right" spinBox="true" caption="262l, resolution 2.5Å" /> '''STRUCTURAL CHARACTERI... |
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[[Image:262l.jpg|left|200px]]<br /><applet load="262l" size=" | [[Image:262l.jpg|left|200px]]<br /><applet load="262l" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="262l, resolution 2.5Å" /> | caption="262l, resolution 2.5Å" /> | ||
'''STRUCTURAL CHARACTERISATION OF AN ENGINEERED TANDEM REPEAT CONTRASTS THE IMPORTANCE OF CONTEXT AND SEQUENCE IN PROTEIN FOLDING'''<br /> | '''STRUCTURAL CHARACTERISATION OF AN ENGINEERED TANDEM REPEAT CONTRASTS THE IMPORTANCE OF CONTEXT AND SEQUENCE IN PROTEIN FOLDING'''<br /> | ||
==Overview== | ==Overview== | ||
To test a different approach to understanding the relationship between the | To test a different approach to understanding the relationship between the sequence of part of a protein and its conformation in the overall folded structure, the amino acid sequence corresponding to an alpha-helix of T4 lysozyme was duplicated in tandem. The presence of such a sequence repeat provides the protein with "choices" during folding. The mutant protein folds with almost wild-type stability, is active, and crystallizes in two different space groups, one isomorphous with wild type and the other with two molecules in the asymmetric unit. The fold of the mutant is essentially the same in all cases, showing that the inserted segment has a well-defined structure. More than half of the inserted residues are themselves helical and extend the helix present in the wild-type protein. Participation of additional duplicated residues in this helix would have required major disruption of the parent structure. The results clearly show that the residues within the duplicated sequence tend to maintain a helical conformation even though the packing interactions with the remainder of the protein are different from those of the original helix. It supports the hypothesis that the structures of individual alpha-helices are determined predominantly by the nature of the amino acids within the helix, rather than the structural environment provided by the rest of the protein. | ||
==About this Structure== | ==About this Structure== | ||
262L 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:// | 262L 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=262L OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Lysozyme]] | [[Category: Lysozyme]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Baase, W | [[Category: Baase, W A.]] | ||
[[Category: Matthews, B | [[Category: Matthews, B W.]] | ||
[[Category: Sagermann, M.]] | [[Category: Sagermann, M.]] | ||
[[Category: engineered tandem repeat]] | [[Category: engineered tandem repeat]] | ||
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[[Category: t4 lysozyme]] | [[Category: t4 lysozyme]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:22:06 2008'' | ||
Revision as of 17:22, 21 February 2008
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STRUCTURAL CHARACTERISATION OF AN ENGINEERED TANDEM REPEAT CONTRASTS THE IMPORTANCE OF CONTEXT AND SEQUENCE IN PROTEIN FOLDING
OverviewOverview
To test a different approach to understanding the relationship between the sequence of part of a protein and its conformation in the overall folded structure, the amino acid sequence corresponding to an alpha-helix of T4 lysozyme was duplicated in tandem. The presence of such a sequence repeat provides the protein with "choices" during folding. The mutant protein folds with almost wild-type stability, is active, and crystallizes in two different space groups, one isomorphous with wild type and the other with two molecules in the asymmetric unit. The fold of the mutant is essentially the same in all cases, showing that the inserted segment has a well-defined structure. More than half of the inserted residues are themselves helical and extend the helix present in the wild-type protein. Participation of additional duplicated residues in this helix would have required major disruption of the parent structure. The results clearly show that the residues within the duplicated sequence tend to maintain a helical conformation even though the packing interactions with the remainder of the protein are different from those of the original helix. It supports the hypothesis that the structures of individual alpha-helices are determined predominantly by the nature of the amino acids within the helix, rather than the structural environment provided by the rest of the protein.
About this StructureAbout this Structure
262L 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.
ReferenceReference
Structural characterization of an engineered tandem repeat contrasts the importance of context and sequence in protein folding., Sagermann M, Baase WA, Matthews BW, Proc Natl Acad Sci U S A. 1999 May 25;96(11):6078-83. PMID:10339544
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