1a4q: Difference between revisions

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[[Image:1a4q.gif|left|200px]]<br /><applet load="1a4q" size="350" color="white" frame="true" align="right" spinBox="true"
[[Image:1a4q.gif|left|200px]]
caption="1a4q, resolution 1.9&Aring;" />
 
'''INFLUENZA VIRUS B/BEIJING/1/87 NEURAMINIDASE COMPLEXED WITH DIHYDROPYRAN-PHENETHYL-PROPYL-CARBOXAMIDE'''<br />
{{Structure
|PDB= 1a4q |SIZE=350|CAPTION= <scene name='initialview01'>1a4q</scene>, resolution 1.9&Aring;
|SITE= <scene name='pdbsite=CHA:High+Affinity+Ca+Binding+Site+In+Chain+A'>CHA</scene>, <scene name='pdbsite=CHB:High+Affinity+Ca+Binding+Site+In+Chain+B'>CHB</scene>, <scene name='pdbsite=CLA:Low+Affinity+Ca+Binding+Site+In+Chain+A'>CLA</scene>, <scene name='pdbsite=CLB:Low+Affinity+Ca+Binding+Site+In+Chain+B'>CLB</scene>, <scene name='pdbsite=LIA:Binding+Site+For+Inhibitor+In+Chain+A'>LIA</scene> and <scene name='pdbsite=LIB:Binding+Site+For+Inhibitor+In+Chain+B'>LIB</scene>
|LIGAND= <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene> and <scene name='pdbligand=DPC:5-ACETYLAMINO-4-AMINO-6-(PHENETHYL-PROPYL-CARBAMOYL)-5,6-DIHYDRO-4H-PYRAN-2-CARBOXYLIC ACID'>DPC</scene>
|ACTIVITY= [http://en.wikipedia.org/wiki/Exo-alpha-sialidase Exo-alpha-sialidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.18 3.2.1.18]
|GENE=
}}
 
'''INFLUENZA VIRUS B/BEIJING/1/87 NEURAMINIDASE COMPLEXED WITH DIHYDROPYRAN-PHENETHYL-PROPYL-CARBOXAMIDE'''
 


==Overview==
==Overview==
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==About this Structure==
==About this Structure==
1A4Q is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Influenza_b_virus Influenza b virus] with <scene name='pdbligand=NAG:'>NAG</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=DPC:'>DPC</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Exo-alpha-sialidase Exo-alpha-sialidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.18 3.2.1.18] Known structural/functional Sites: <scene name='pdbsite=CHA:High+Affinity+Ca+Binding+Site+In+Chain+A'>CHA</scene>, <scene name='pdbsite=CHB:High+Affinity+Ca+Binding+Site+In+Chain+B'>CHB</scene>, <scene name='pdbsite=CLA:Low+Affinity+Ca+Binding+Site+In+Chain+A'>CLA</scene>, <scene name='pdbsite=CLB:Low+Affinity+Ca+Binding+Site+In+Chain+B'>CLB</scene>, <scene name='pdbsite=LIA:Binding+Site+For+Inhibitor+In+Chain+A'>LIA</scene> and <scene name='pdbsite=LIB:Binding+Site+For+Inhibitor+In+Chain+B'>LIB</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A4Q OCA].  
1A4Q is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Influenza_b_virus Influenza b virus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A4Q OCA].  


==Reference==
==Reference==
Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 2. Crystallographic and molecular modeling study of complexes of 4-amino-4H-pyran-6-carboxamides and sialidase from influenza virus types A and B., Taylor NR, Cleasby A, Singh O, Skarzynski T, Wonacott AJ, Smith PW, Sollis SL, Howes PD, Cherry PC, Bethell R, Colman P, Varghese J, J Med Chem. 1998 Mar 12;41(6):798-807. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9526556 9526556]
Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 2. Crystallographic and molecular modeling study of complexes of 4-amino-4H-pyran-6-carboxamides and sialidase from influenza virus types A and B., Taylor NR, Cleasby A, Singh O, Skarzynski T, Wonacott AJ, Smith PW, Sollis SL, Howes PD, Cherry PC, Bethell R, Colman P, Varghese J, J Med Chem. 1998 Mar 12;41(6):798-807. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9526556 9526556]
[[Category: Exo-alpha-sialidase]]
[[Category: Exo-alpha-sialidase]]
[[Category: Influenza b virus]]
[[Category: Influenza b virus]]
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[[Category: hydrolase]]
[[Category: hydrolase]]


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Revision as of 10:52, 20 March 2008

File:1a4q.gif


PDB ID 1a4q

Drag the structure with the mouse to rotate
, resolution 1.9Å
Sites: , , , , and
Ligands: , and
Activity: Exo-alpha-sialidase, with EC number 3.2.1.18
Coordinates: save as pdb, mmCIF, xml



INFLUENZA VIRUS B/BEIJING/1/87 NEURAMINIDASE COMPLEXED WITH DIHYDROPYRAN-PHENETHYL-PROPYL-CARBOXAMIDE


OverviewOverview

The first paper in this series (see previous article) described structure-activity studies of carboxamide analogues of zanamivir binding to influenza virus sialidase types A and B and showed that inhibitory activity of these compounds was much greater against influenza A enzyme. To understand the large differences in affinities, a number of protein-ligand complexes have been investigated using crystallography and molecular dynamics. The crystallographic studies show that the binding of ligands containing tertiary amide groups is accompanied by the formation of an intramolecular planar salt bridge between two amino acid residues in the active site of the enzyme. It is proposed that the unexpected strong binding of these inhibitors is a result of the burial of hydrophobic surface area and salt-bridge formation in an environment of low dielectric. In sialidase from type A virus, binding of the carboxamide moeity and salt-bridge formation have only a minor effect on the positions of the surrounding residues, whereas in type B enzyme, significant distortion of the protein is observed. The results suggest that the decreased affinity in enzyme from influenza B is directly correlated with the small changes that occur in the amino acid residue interactions accompanying ligand binding. Molecular dynamics calculations have shown that the tendency for salt-bridge formation is greater in influenza A sialidase than influenza B sialidase and that this tendency is a useful descriptor for the prediction of inhibitor potency.

About this StructureAbout this Structure

1A4Q is a Single protein structure of sequence from Influenza b virus. Full crystallographic information is available from OCA.

ReferenceReference

Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 2. Crystallographic and molecular modeling study of complexes of 4-amino-4H-pyran-6-carboxamides and sialidase from influenza virus types A and B., Taylor NR, Cleasby A, Singh O, Skarzynski T, Wonacott AJ, Smith PW, Sollis SL, Howes PD, Cherry PC, Bethell R, Colman P, Varghese J, J Med Chem. 1998 Mar 12;41(6):798-807. PMID:9526556

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