1hvw
From Proteopedia
(New page: 200px<br /><applet load="1hvw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hvw" /> '''HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A...) |
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| - | [[Image:1hvw.gif|left|200px]]<br /><applet load="1hvw" size=" | + | [[Image:1hvw.gif|left|200px]]<br /><applet load="1hvw" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1hvw" /> | caption="1hvw" /> | ||
'''HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A'''<br /> | '''HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A'''<br /> | ||
==Overview== | ==Overview== | ||
| - | omega-Atracotoxin-Hv1a is an insect-specific neurotoxin whose phylogenetic | + | omega-Atracotoxin-Hv1a is an insect-specific neurotoxin whose phylogenetic specificity derives from its ability to antagonize insect, but not vertebrate, voltage-gated calcium channels. In order to help understand its mechanism of action and to enhance its utility as a lead compound for insecticide development, we used a combination of protein engineering and site-directed mutagenesis to probe the toxin for key functional regions. First, we constructed a Hairpinless mutant in which the C-terminal beta-hairpin, which is highly conserved in this family of neurotoxins, was excised without affecting the fold of the residual disulfide-rich core of the toxin. The Hairpinless mutant was devoid of insecticidal activity, indicating the functional importance of the hairpin. We subsequently developed a highly efficient system for production of recombinant toxin and then probed the hairpin for key functional residues using alanine-scanning mutagenesis followed by a second round of mutagenesis based on initial "hits" from the alanine scan. This revealed that two spatially proximal residues, Asn(27) and Arg(35), form a contiguous molecular surface that is essential for toxin activity. We propose that this surface of the beta-hairpin is a key site for interaction of the toxin with insect calcium channels. |
==About this Structure== | ==About this Structure== | ||
| - | 1HVW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | + | 1HVW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HVW OCA]. |
==Reference== | ==Reference== | ||
Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a., Tedford HW, Fletcher JI, King GF, J Biol Chem. 2001 Jul 13;276(28):26568-76. Epub 2001 Apr 19. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11313356 11313356] | Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a., Tedford HW, Fletcher JI, King GF, J Biol Chem. 2001 Jul 13;276(28):26568-76. Epub 2001 Apr 19. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11313356 11313356] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Fletcher, J | + | [[Category: Fletcher, J I.]] |
| - | [[Category: King, G | + | [[Category: King, G F.]] |
[[Category: beta-hairpin]] | [[Category: beta-hairpin]] | ||
[[Category: cystine knot]] | [[Category: cystine knot]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:05:24 2008'' |
Revision as of 11:05, 21 February 2008
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HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A
Overview
omega-Atracotoxin-Hv1a is an insect-specific neurotoxin whose phylogenetic specificity derives from its ability to antagonize insect, but not vertebrate, voltage-gated calcium channels. In order to help understand its mechanism of action and to enhance its utility as a lead compound for insecticide development, we used a combination of protein engineering and site-directed mutagenesis to probe the toxin for key functional regions. First, we constructed a Hairpinless mutant in which the C-terminal beta-hairpin, which is highly conserved in this family of neurotoxins, was excised without affecting the fold of the residual disulfide-rich core of the toxin. The Hairpinless mutant was devoid of insecticidal activity, indicating the functional importance of the hairpin. We subsequently developed a highly efficient system for production of recombinant toxin and then probed the hairpin for key functional residues using alanine-scanning mutagenesis followed by a second round of mutagenesis based on initial "hits" from the alanine scan. This revealed that two spatially proximal residues, Asn(27) and Arg(35), form a contiguous molecular surface that is essential for toxin activity. We propose that this surface of the beta-hairpin is a key site for interaction of the toxin with insect calcium channels.
About this Structure
1HVW is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
Reference
Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a., Tedford HW, Fletcher JI, King GF, J Biol Chem. 2001 Jul 13;276(28):26568-76. Epub 2001 Apr 19. PMID:11313356
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