1br5: Difference between revisions
New page: left|200px<br /><applet load="1br5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1br5, resolution 2.5Å" /> '''RICIN A CHAIN (RECOMB... |
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[[Image:1br5.gif|left|200px]]<br /><applet load="1br5" size=" | [[Image:1br5.gif|left|200px]]<br /><applet load="1br5" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1br5, resolution 2.5Å" /> | caption="1br5, resolution 2.5Å" /> | ||
'''RICIN A CHAIN (RECOMBINANT) COMPLEX WITH NEOPTERIN'''<br /> | '''RICIN A CHAIN (RECOMBINANT) COMPLEX WITH NEOPTERIN'''<br /> | ||
==Overview== | ==Overview== | ||
Ricin is a potent cytotoxin which has been used widely in the construction | Ricin is a potent cytotoxin which has been used widely in the construction of therapeutic agents such as immunotoxins. Recently it has been used by governments and underground groups as a poison. There is interest in identifying and designing effective inhibitors of the ricin A chain (RTA). In this study computer-assisted searches indicated that pterins might bind in the RTA active site which normally recognizes a specific adenine base on rRNA. Kinetic assays showed that pteroic acid could inhibit RTA activity with an apparent Ki of 0.6 mM. A 2.3 A crystal structure of the complex revealed the mode of binding. The pterin ring displaces Tyr80 and binds in the adenine pocket making specific hydrogen bonds to active site residues. The benzoate moiety of pteroic acid binds on the opposite side of Tyr80 making van der Waals contact with the Tyr ring and forming a hydrogen bond with Asn78. Neopterin, a propane triol derivative of pterin, also binds to RTA as revealed by the X-ray structure of its complex with RTA. Neither pterin-6-carboxylic acid nor folic acid bind to the crystal or act as inhibitors. The models observed suggest alterations to the pterin moiety which may produce more potent and specific RTA inhibitors. | ||
==About this Structure== | ==About this Structure== | ||
1BR5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ricinus_communis Ricinus communis] with NEO as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/rRNA_N-glycosylase rRNA N-glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.22 3.2.2.22] Full crystallographic information is available from [http:// | 1BR5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ricinus_communis Ricinus communis] with <scene name='pdbligand=NEO:'>NEO</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/rRNA_N-glycosylase rRNA N-glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.22 3.2.2.22] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BR5 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Day, P.]] | [[Category: Day, P.]] | ||
[[Category: Hollis, T.]] | [[Category: Hollis, T.]] | ||
[[Category: Milne, G | [[Category: Milne, G W.A.]] | ||
[[Category: Monzingo, A | [[Category: Monzingo, A F.]] | ||
[[Category: Robertus, J | [[Category: Robertus, J D.]] | ||
[[Category: Svinth, M.]] | [[Category: Svinth, M.]] | ||
[[Category: Yan, X.]] | [[Category: Yan, X.]] | ||
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[[Category: glycosidase]] | [[Category: glycosidase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:58:13 2008'' | ||
Revision as of 12:58, 21 February 2008
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RICIN A CHAIN (RECOMBINANT) COMPLEX WITH NEOPTERIN
OverviewOverview
Ricin is a potent cytotoxin which has been used widely in the construction of therapeutic agents such as immunotoxins. Recently it has been used by governments and underground groups as a poison. There is interest in identifying and designing effective inhibitors of the ricin A chain (RTA). In this study computer-assisted searches indicated that pterins might bind in the RTA active site which normally recognizes a specific adenine base on rRNA. Kinetic assays showed that pteroic acid could inhibit RTA activity with an apparent Ki of 0.6 mM. A 2.3 A crystal structure of the complex revealed the mode of binding. The pterin ring displaces Tyr80 and binds in the adenine pocket making specific hydrogen bonds to active site residues. The benzoate moiety of pteroic acid binds on the opposite side of Tyr80 making van der Waals contact with the Tyr ring and forming a hydrogen bond with Asn78. Neopterin, a propane triol derivative of pterin, also binds to RTA as revealed by the X-ray structure of its complex with RTA. Neither pterin-6-carboxylic acid nor folic acid bind to the crystal or act as inhibitors. The models observed suggest alterations to the pterin moiety which may produce more potent and specific RTA inhibitors.
About this StructureAbout this Structure
1BR5 is a Single protein structure of sequence from Ricinus communis with as ligand. Active as rRNA N-glycosylase, with EC number 3.2.2.22 Full crystallographic information is available from OCA.
ReferenceReference
Structure-based identification of a ricin inhibitor., Yan X, Hollis T, Svinth M, Day P, Monzingo AF, Milne GW, Robertus JD, J Mol Biol. 1997 Mar 14;266(5):1043-9. PMID:9086280
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