1r63
From Proteopedia
(New page: 200px<br /><applet load="1r63" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r63" /> '''STRUCTURAL ROLE OF A BURIED SALT BRIDGE IN T...) |
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| - | [[Image:1r63.gif|left|200px]]<br /><applet load="1r63" size=" | + | [[Image:1r63.gif|left|200px]]<br /><applet load="1r63" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1r63" /> | caption="1r63" /> | ||
'''STRUCTURAL ROLE OF A BURIED SALT BRIDGE IN THE 434 REPRESSOR DNA-BINDING DOMAIN, NMR, 20 STRUCTURES'''<br /> | '''STRUCTURAL ROLE OF A BURIED SALT BRIDGE IN THE 434 REPRESSOR DNA-BINDING DOMAIN, NMR, 20 STRUCTURES'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The independently folding 63-residue N-terminal DNA-binding domain of the | + | The independently folding 63-residue N-terminal DNA-binding domain of the 434 repressor, 434(1-63), contains a buried Arg10-Glu35 salt bridge. A corresponding salt bridge is found in a variety of prokaryotic and eukaryotic DNA-binding proteins with helix-turn-helix motifs. Here, the NMR solution structures of 434(1-63) and the mutant protein 434[R10M](1-63) were determined to investigate the structural role of this salt bridge. Both proteins contain the same type of global fold, with five alpha-helices and a helix-turn-helix motif formed by the helices II and III. The primary structural difference caused by the Arg10 --> Met mutation is a translation of helix I along its axis relative to the helix II-turn-helix III motif. This limited conformational change is paralleled by a 9 kJ M(-1) decrease of the stability of the folded mutant protein in aqueous solution at pH 4.8. It affects the pKa value of Glu19 as well as the population of a hydrogen bond between the backbone amide proton of Asn16 and the side-chain carboxylate group of Glu19. Using the crystal structure of the 434 repressor dimer complexed with the operator DNA as a basis, model building of the DNA complex with the NMR structure of 434[R10M](1-63) shows that Asn16, which is located on the protein surface, makes direct contact with the DNA and indicates that the point mutation Arg10 --> Met should also lead to modifications of the protein-protein contacts in the complex. |
==About this Structure== | ==About this Structure== | ||
| - | 1R63 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_434 Bacteriophage 434]. Full crystallographic information is available from [http:// | + | 1R63 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_434 Bacteriophage 434]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R63 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Billeter, M.]] | [[Category: Billeter, M.]] | ||
| - | [[Category: Pervushin, K | + | [[Category: Pervushin, K V.]] |
[[Category: Siegal, G.]] | [[Category: Siegal, G.]] | ||
[[Category: Wuthrich, K.]] | [[Category: Wuthrich, K.]] | ||
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[[Category: phage 434 repressor]] | [[Category: phage 434 repressor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:47:26 2008'' |
Revision as of 12:47, 21 February 2008
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STRUCTURAL ROLE OF A BURIED SALT BRIDGE IN THE 434 REPRESSOR DNA-BINDING DOMAIN, NMR, 20 STRUCTURES
Overview
The independently folding 63-residue N-terminal DNA-binding domain of the 434 repressor, 434(1-63), contains a buried Arg10-Glu35 salt bridge. A corresponding salt bridge is found in a variety of prokaryotic and eukaryotic DNA-binding proteins with helix-turn-helix motifs. Here, the NMR solution structures of 434(1-63) and the mutant protein 434[R10M](1-63) were determined to investigate the structural role of this salt bridge. Both proteins contain the same type of global fold, with five alpha-helices and a helix-turn-helix motif formed by the helices II and III. The primary structural difference caused by the Arg10 --> Met mutation is a translation of helix I along its axis relative to the helix II-turn-helix III motif. This limited conformational change is paralleled by a 9 kJ M(-1) decrease of the stability of the folded mutant protein in aqueous solution at pH 4.8. It affects the pKa value of Glu19 as well as the population of a hydrogen bond between the backbone amide proton of Asn16 and the side-chain carboxylate group of Glu19. Using the crystal structure of the 434 repressor dimer complexed with the operator DNA as a basis, model building of the DNA complex with the NMR structure of 434[R10M](1-63) shows that Asn16, which is located on the protein surface, makes direct contact with the DNA and indicates that the point mutation Arg10 --> Met should also lead to modifications of the protein-protein contacts in the complex.
About this Structure
1R63 is a Single protein structure of sequence from Bacteriophage 434. Full crystallographic information is available from OCA.
Reference
Structural role of a buried salt bridge in the 434 repressor DNA-binding domain., Pervushin K, Billeter M, Siegal G, Wuthrich K, J Mol Biol. 1996 Dec 20;264(5):1002-12. PMID:9000626
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