1ug4: Difference between revisions
New page: left|200px<br /><applet load="1ug4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ug4, resolution 1.6Å" /> '''Crystal Structure of ... |
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[[Image:1ug4.gif|left|200px]]<br /><applet load="1ug4" size=" | [[Image:1ug4.gif|left|200px]]<br /><applet load="1ug4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ug4, resolution 1.6Å" /> | caption="1ug4, resolution 1.6Å" /> | ||
'''Crystal Structure of Cardiotoxin VI from Taiwan Cobra (Naja atra) Venom'''<br /> | '''Crystal Structure of Cardiotoxin VI from Taiwan Cobra (Naja atra) Venom'''<br /> | ||
==Overview== | ==Overview== | ||
Natural homologues of cobra cardiotoxins (CTXs) were classified into two | Natural homologues of cobra cardiotoxins (CTXs) were classified into two structural subclasses of group I and II based on the amino acid sequence and circular dichroism analysis, but the exact differences in their three-dimensional structures and biological significance remain elusive. We show by circular dichroism, NMR spectroscopic, and X-ray crystallographic analyses of a newly purified group I CTX A6 from eastern Taiwan cobra (Naja atra) venoms that its loop I conformation adopts a type VIa turn with a cis peptide bond located between two proline residues of PPxY. A similar "banana-twisted" conformation can be observed in other group I CTXs and also in cyclolinopeptide A and its analogues. By binding to the membrane environment, group I CTX undergoes a conformational change to adopt a more extended hydrophobic domain with beta-sheet twisting closer to the one adopted by group II CTX. This result resolves a discrepancy in the CTX structural difference reported previously between solution as well as crystal state and shows that, in addition to the hydrophobicity, the exact loop I conformation also plays an important role in CTX-membrane interaction. Potential protein targets of group I CTXs after cell internalization are also discussed on the basis of the determined loop I conformation. | ||
==About this Structure== | ==About this Structure== | ||
1UG4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Naja_atra Naja atra]. Full crystallographic information is available from [http:// | 1UG4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Naja_atra Naja atra]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UG4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Naja atra]] | [[Category: Naja atra]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Chen, C | [[Category: Chen, C J.]] | ||
[[Category: Chung, F | [[Category: Chung, F Y.]] | ||
[[Category: Wu, W | [[Category: Wu, W G.]] | ||
[[Category: cardiotoxin]] | [[Category: cardiotoxin]] | ||
[[Category: cobra]] | [[Category: cobra]] | ||
[[Category: venom]] | [[Category: venom]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:24:12 2008'' | ||
Revision as of 13:24, 21 February 2008
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Crystal Structure of Cardiotoxin VI from Taiwan Cobra (Naja atra) Venom
Overview
Natural homologues of cobra cardiotoxins (CTXs) were classified into two structural subclasses of group I and II based on the amino acid sequence and circular dichroism analysis, but the exact differences in their three-dimensional structures and biological significance remain elusive. We show by circular dichroism, NMR spectroscopic, and X-ray crystallographic analyses of a newly purified group I CTX A6 from eastern Taiwan cobra (Naja atra) venoms that its loop I conformation adopts a type VIa turn with a cis peptide bond located between two proline residues of PPxY. A similar "banana-twisted" conformation can be observed in other group I CTXs and also in cyclolinopeptide A and its analogues. By binding to the membrane environment, group I CTX undergoes a conformational change to adopt a more extended hydrophobic domain with beta-sheet twisting closer to the one adopted by group II CTX. This result resolves a discrepancy in the CTX structural difference reported previously between solution as well as crystal state and shows that, in addition to the hydrophobicity, the exact loop I conformation also plays an important role in CTX-membrane interaction. Potential protein targets of group I CTXs after cell internalization are also discussed on the basis of the determined loop I conformation.
About this Structure
1UG4 is a Single protein structure of sequence from Naja atra. Full crystallographic information is available from OCA.
Reference
Structural difference between group I and group II cobra cardiotoxins: X-ray, NMR, and CD analysis of the effect of cis-proline conformation on three-fingered toxins., Chen TS, Chung FY, Tjong SC, Goh KS, Huang WN, Chien KY, Wu PL, Lin HC, Chen CJ, Wu WG, Biochemistry. 2005 May 24;44(20):7414-26. PMID:15895985
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