1ab7: Difference between revisions
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==NMR 15N RELAXATION AND STRUCTURAL STUDIES REVEAL CONFORMATIONAL EXCHANGE IN BARSTAR C40/82A, 30 STRUCTURES== | |||
<StructureSection load='1ab7' size='340' side='right'caption='[[1ab7]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1ab7]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_amyloliquefaciens Bacillus amyloliquefaciens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AB7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AB7 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1ab7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ab7 OCA], [https://pdbe.org/1ab7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ab7 RCSB], [https://www.ebi.ac.uk/pdbsum/1ab7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ab7 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/BARS_BACAM BARS_BACAM] Inhibitor of the ribonuclease barnase. Forms a one-to-one non-covalent complex. | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ab/1ab7_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1ab7 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Barstar an 89-residue protein consisting of four helices and a three-stranded parallel beta-sheet, is the intracellular inhibitor of the endoribonuclease barnase. Barstar C40/82A, a mutant in which the two cysteine residues have been replaced by alanine, has been used as a pseudo wild-type in folding studies and in the crystal structure of the barnase:barstar C40/82A complex. We have determined a high resolution solution structure of barstar C40/82A. The structures of barstar C40/82A and the wild-type are superimposable. A comparison with the crystal structure of the barnase:barstar C40/82A complex revealed subtle differences in the regions involved in the binding of barstar to barnase. Side-chain rotations of residues Asn33, Asp35 and Asp39 and a movement of the binding loop (Pro27-Glu32) towards the binding site of barnase facilitate the formation of interface hydrogen bonds and aromatic contacts in the complex. Extreme line broadening and missing signals in 1H-15N correlation spectra indicate substantial conformational exchange for a large subset of residues. 15N relaxation data at two magnetic field strengths, 11.74 T and 14.10 T, were used to estimate exchange contributions and to map the spectral density function at five frequencies: 0, 50, 60, 450 and 540 MHz. Based on these results, model-free calculations with the inclusion of estimated exchange contributions were used to derive order parameters and internal correlation times. The validity of this approach has been investigated with model-free calculations that incorporate longitudinal relaxation rates and heteronuclear 1H-15N NOE data only at 11.74 T and 14.10 T. The relaxation data suggest substantial conformational exchange in regions of barstar C40/82A, including the binding loop, the second and the third helices, and the second and the third strands. Amide proton exchange experiments suggest a stable hydrogen bond network for all helices and sheets except the third helix and the C-terminal of the second and the third strands. The combined results indicate a rigid body movement of the second helix and twisting motions of the beta-sheet of barstar, which might be important for the interaction with barnase. | |||
NMR 15N relaxation and structural studies reveal slow conformational exchange in barstar C40/82A.,Wong KB, Fersht AR, Freund SM J Mol Biol. 1997 May 2;268(2):494-511. PMID:9159486<ref>PMID:9159486</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1ab7" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Barstar 3D structures|Barstar 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Bacillus amyloliquefaciens]] | [[Category: Bacillus amyloliquefaciens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Fersht | [[Category: Fersht AR]] | ||
[[Category: Freund | [[Category: Freund SMV]] | ||
[[Category: Wong | [[Category: Wong KB]] | ||
Latest revision as of 11:12, 22 May 2024
NMR 15N RELAXATION AND STRUCTURAL STUDIES REVEAL CONFORMATIONAL EXCHANGE IN BARSTAR C40/82A, 30 STRUCTURESNMR 15N RELAXATION AND STRUCTURAL STUDIES REVEAL CONFORMATIONAL EXCHANGE IN BARSTAR C40/82A, 30 STRUCTURES
Structural highlights
FunctionBARS_BACAM Inhibitor of the ribonuclease barnase. Forms a one-to-one non-covalent complex. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBarstar an 89-residue protein consisting of four helices and a three-stranded parallel beta-sheet, is the intracellular inhibitor of the endoribonuclease barnase. Barstar C40/82A, a mutant in which the two cysteine residues have been replaced by alanine, has been used as a pseudo wild-type in folding studies and in the crystal structure of the barnase:barstar C40/82A complex. We have determined a high resolution solution structure of barstar C40/82A. The structures of barstar C40/82A and the wild-type are superimposable. A comparison with the crystal structure of the barnase:barstar C40/82A complex revealed subtle differences in the regions involved in the binding of barstar to barnase. Side-chain rotations of residues Asn33, Asp35 and Asp39 and a movement of the binding loop (Pro27-Glu32) towards the binding site of barnase facilitate the formation of interface hydrogen bonds and aromatic contacts in the complex. Extreme line broadening and missing signals in 1H-15N correlation spectra indicate substantial conformational exchange for a large subset of residues. 15N relaxation data at two magnetic field strengths, 11.74 T and 14.10 T, were used to estimate exchange contributions and to map the spectral density function at five frequencies: 0, 50, 60, 450 and 540 MHz. Based on these results, model-free calculations with the inclusion of estimated exchange contributions were used to derive order parameters and internal correlation times. The validity of this approach has been investigated with model-free calculations that incorporate longitudinal relaxation rates and heteronuclear 1H-15N NOE data only at 11.74 T and 14.10 T. The relaxation data suggest substantial conformational exchange in regions of barstar C40/82A, including the binding loop, the second and the third helices, and the second and the third strands. Amide proton exchange experiments suggest a stable hydrogen bond network for all helices and sheets except the third helix and the C-terminal of the second and the third strands. The combined results indicate a rigid body movement of the second helix and twisting motions of the beta-sheet of barstar, which might be important for the interaction with barnase. NMR 15N relaxation and structural studies reveal slow conformational exchange in barstar C40/82A.,Wong KB, Fersht AR, Freund SM J Mol Biol. 1997 May 2;268(2):494-511. PMID:9159486[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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