1qhe: Difference between revisions

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[[Image:1qhe.png|left|200px]]
==ENERGETICS OF A HYDROGEN BOND (CHARGED AND NEUTRAL) AND OF A CATION-PI INTERACTION IN APOFLAVODOXIN==
<StructureSection load='1qhe' size='340' side='right' caption='[[1qhe]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1qhe]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Nostoc_sp. Nostoc sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QHE OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1QHE FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene><br>
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1ftg|1ftg]]</td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1qhe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qhe OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1qhe RCSB], [http://www.ebi.ac.uk/pdbsum/1qhe PDBsum]</span></td></tr>
<table>
== 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/qh/1qhe_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/chain_selection.php?pdb_ID=2ata ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Anabaena apoflavodoxin contains a single histidine residue (H34) that interacts with two aromatic residues (F7 and Y47). The histidine and phenylalanine rings are almost coplanar and they can establish a cation-pi interaction when the histidine is protonated. The histidine and tyrosine side-chains are engaged in a hydrogen bond, which is their only contact. We analyse the energetics of these interactions using p Ka-shift analysis, double-mutant cycle analysis at two pH values, and X-ray crystallography. The H/F interaction is very weak when the histidine is neutral, but it is strengthened by 0.5 kcal mol-1on histidine protonation. Supporting this fact, the histidine p Kain a F7L mutant is 0.4 pH units lower than in wild-type. The strength of the H/Y hydrogen bond is 0.7 kcal mol-1when the histidine is charged, and it becomes stronger (1.3 kcal mol-1) when the histidine is neutral. This is consistent with our observation that the (H34)Nepsilon2-OH(Y47) distance is slightly shorter in the apoflavodoxin structure at pH 9.0 than in the previously reported structure at pH 6.0. It is also consistent with a histidine p Kavalue 0.6 pH units higher in a Y47F mutant than in the wild-type protein. We suggest that the higher stability of the neutral hydrogen bond could be due to a higher desolvation penalty of the charged hydrogen bond that would offset its more favourable enthalpy of formation. The relationship between hydrogen bond strength and the contribution of hydrogen bonds to protein stability is discussed.


{{STRUCTURE_1qhe|  PDB=1qhe  |  SCENE=  }}
Energetics of a hydrogen bond (charged and neutral) and of a cation-pi interaction in apoflavodoxin.,Fernandez-Recio J, Romero A, Sancho J J Mol Biol. 1999 Jul 2;290(1):319-30. PMID:10388575<ref>PMID:10388575</ref>


===ENERGETICS OF A HYDROGEN BOND (CHARGED AND NEUTRAL) AND OF A CATION-PI INTERACTION IN APOFLAVODOXIN===
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
 
</div>
{{ABSTRACT_PUBMED_10388575}}
 
==About this Structure==
[[1qhe]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Nostoc_sp. Nostoc sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QHE OCA].


==See Also==
==See Also==
*[[Flavodoxin|Flavodoxin]]
*[[Flavodoxin|Flavodoxin]]
 
== References ==
==Reference==
<references/>
<ref group="xtra">PMID:010388575</ref><references group="xtra"/>
__TOC__
</StructureSection>
[[Category: Nostoc sp.]]
[[Category: Nostoc sp.]]
[[Category: Fernandez-Recio, J.]]
[[Category: Fernandez-Recio, J.]]

Revision as of 23:52, 28 September 2014

ENERGETICS OF A HYDROGEN BOND (CHARGED AND NEUTRAL) AND OF A CATION-PI INTERACTION IN APOFLAVODOXINENERGETICS OF A HYDROGEN BOND (CHARGED AND NEUTRAL) AND OF A CATION-PI INTERACTION IN APOFLAVODOXIN

Structural highlights

1qhe is a 1 chain structure with sequence from Nostoc sp.. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Related:1ftg
Resources:FirstGlance, OCA, RCSB, PDBsum

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 PubMed

Anabaena apoflavodoxin contains a single histidine residue (H34) that interacts with two aromatic residues (F7 and Y47). The histidine and phenylalanine rings are almost coplanar and they can establish a cation-pi interaction when the histidine is protonated. The histidine and tyrosine side-chains are engaged in a hydrogen bond, which is their only contact. We analyse the energetics of these interactions using p Ka-shift analysis, double-mutant cycle analysis at two pH values, and X-ray crystallography. The H/F interaction is very weak when the histidine is neutral, but it is strengthened by 0.5 kcal mol-1on histidine protonation. Supporting this fact, the histidine p Kain a F7L mutant is 0.4 pH units lower than in wild-type. The strength of the H/Y hydrogen bond is 0.7 kcal mol-1when the histidine is charged, and it becomes stronger (1.3 kcal mol-1) when the histidine is neutral. This is consistent with our observation that the (H34)Nepsilon2-OH(Y47) distance is slightly shorter in the apoflavodoxin structure at pH 9.0 than in the previously reported structure at pH 6.0. It is also consistent with a histidine p Kavalue 0.6 pH units higher in a Y47F mutant than in the wild-type protein. We suggest that the higher stability of the neutral hydrogen bond could be due to a higher desolvation penalty of the charged hydrogen bond that would offset its more favourable enthalpy of formation. The relationship between hydrogen bond strength and the contribution of hydrogen bonds to protein stability is discussed.

Energetics of a hydrogen bond (charged and neutral) and of a cation-pi interaction in apoflavodoxin.,Fernandez-Recio J, Romero A, Sancho J J Mol Biol. 1999 Jul 2;290(1):319-30. PMID:10388575[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. ↑ Fernandez-Recio J, Romero A, Sancho J. Energetics of a hydrogen bond (charged and neutral) and of a cation-pi interaction in apoflavodoxin. J Mol Biol. 1999 Jul 2;290(1):319-30. PMID:10388575 doi:10.1006/jmbi.1999.2863

1qhe, resolution 2.00Å

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