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| {{STRUCTURE_1rcs| PDB=1rcs | SCENE= }} | | {{STRUCTURE_1rcs| PDB=1rcs | SCENE= }} |
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| '''NMR STUDY OF TRP REPRESSOR-OPERATOR DNA COMPLEX'''
| | ===NMR STUDY OF TRP REPRESSOR-OPERATOR DNA COMPLEX=== |
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| ==Overview==
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| The solution structures of the complex between Escherichia coli trp holorepressor and a 20 base-pair consensus operator DNA were determined. The majority of proton chemical shifts of the trp holorepressor and operator DNA were assigned from homonuclear 2D NOESY spectra of selectively deuterated analog-operator DNA complexes and the 3D NOESY-HMQC spectrum of a uniformly 15N-labeled repressor-operator DNA complex. The structures were calculated using restrained molecular dynamics and sequential simulated annealing with 4086 NOE and other experimental constraints. The root-mean-squared deviation (RMSD) among the calculated structures and their mean is 0.9(+/- 0.3)A for the repressor backbone, 1.1(+/- 0.5)A for the DNA backbone, and 1.3(+/- 0.3)A for all heavy atoms. The DNA is deformed to a significant extent from the standard B DNA structure to fit the helix-turn-helix (HTH) segment of the repressor (helices D and E) into its major grooves. Little change is found in the ABCF core of the repressor on complexation in comparison to the free repressor, but changes in the cofactor L-tryptophan binding pocket and the HTH segment are observed. The N-terminal residues (2 to 17) are found to be disordered and do not form stable interactions with DNA. Direct H-bonding to the bases of the operator DNA is consistent with all of our observed NOE constraints. Hydrogen bonds from NH eta 1 and NH eta 2 of Arg69 to O-6 and N-7 of G2 are compatible with the solution structure, as they are with the crystal structure. Other direct H-bonds from Lys72, Ala80, Ile79, Thr83 and Arg84 to base-pair functional groups can also be formed in our solution structures.
| | The line below this paragraph, {{ABSTRACT_PUBMED_8176748}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 8176748 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_8176748}} |
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| ==About this Structure== | | ==About this Structure== |
| 1RCS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RCS OCA]. | | 1RCS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RCS OCA]. |
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| ==Reference== | | ==Reference== |
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| [[Category: Transcription regulation]] | | [[Category: Transcription regulation]] |
| [[Category: Trp]] | | [[Category: Trp]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:20:33 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 10:06:08 2008'' |
