1xt3: Difference between revisions

Revision as of 19:43, 28 July 2008

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File:1xt3.png

Template:STRUCTURE 1xt3

Structure Basis of Venom Citrate-Dependent Heparin Sulfate-Mediated Cell Surface Retention of Cobra Cardiotoxin A3Structure Basis of Venom Citrate-Dependent Heparin Sulfate-Mediated Cell Surface Retention of Cobra Cardiotoxin A3

Template:ABSTRACT PUBMED 15590643

About this StructureAbout this Structure

1XT3 is a Single protein structure of sequence from Naja atra. Full crystallographic information is available from OCA.

ReferenceReference

Structural basis of citrate-dependent and heparan sulfate-mediated cell surface retention of cobra cardiotoxin A3., Lee SC, Guan HH, Wang CH, Huang WN, Tjong SC, Chen CJ, Wu WG, J Biol Chem. 2005 Mar 11;280(10):9567-77. Epub 2004 Dec 6. PMID:15590643

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-'''Structure Basis of Venom Citrate-Dependent Heparin Sulfate-Mediated Cell Surface Retention of Cobra Cardiotoxin A3'''
+===Structure Basis of Venom Citrate-Dependent Heparin Sulfate-Mediated Cell Surface Retention of Cobra Cardiotoxin A3===
-==Overview==
+<!--
-Anionic citrate is a major component of venom, but the role of venom citrate in toxicity other than its inhibitory effect on the cation-dependent action of venom toxins is poorly understood. By immobilizing Chinese hamster ovary cells in microcapillary tubes and heparin on sensor chips, we demonstrated that heparan sulfate-mediated cell retention of the major cardiotoxin (CTX) from the Taiwan cobra, CTX A3, near membrane surfaces is citrate-dependent. X-ray determination of a CTX A3-heparin hexasaccharide complex structure at 2.4 A resolution revealed a molecular mechanism for toxin retention in which heparin-induced conformational changes of CTX A3 lead to citrate-mediated dimerization. A citrate ion bound to Lys-23 and Lys-31 near the tip of loop II stabilizes hydrophobic contact of the CTX A3 homodimer at the functionally important loop I and II regions. Additionally, the heparin hexasaccharide interacts with five CTX A3 molecules in the crystal structure, providing another mechanism whereby the toxin establishes a complex network of interactions that result in a strong interaction with cell surfaces presenting heparan sulfate. Our results suggest a novel role for venom citrate in biological activity and reveal a structural model that explains cell retention of cobra CTX A3 through heparan sulfate-CTX interactions.
+The line below this paragraph, {{ABSTRACT_PUBMED_15590643}}, adds the Publication Abstract to the page
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+{{ABSTRACT_PUBMED_15590643}}
 ==About this Structure==
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 [[Category: Ctx-3]]
 [[Category: Heparin]]
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