1ixt
From Proteopedia
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[[Image:1ixt.gif|left|200px]] | [[Image:1ixt.gif|left|200px]] | ||
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'''Structure of a Novel P-Superfamily Spasmodic Conotoxin Reveals an Inhibitory Cystine Knot Motif''' | '''Structure of a Novel P-Superfamily Spasmodic Conotoxin Reveals an Inhibitory Cystine Knot Motif''' | ||
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==About this Structure== | ==About this Structure== | ||
- | 1IXT is a [[Single protein]] structure | + | 1IXT is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IXT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Norton, R S.]] | [[Category: Norton, R S.]] | ||
[[Category: Olivera, B M.]] | [[Category: Olivera, B M.]] | ||
- | [[Category: | + | [[Category: Conotoxin]] |
- | [[Category: | + | [[Category: Conus gloriamari]] |
- | [[Category: | + | [[Category: Gm9 1]] |
- | [[Category: | + | [[Category: Gm9a]] |
- | [[Category: | + | [[Category: Ick]] |
- | [[Category: | + | [[Category: Inhibitory cystine knot]] |
- | [[Category: | + | [[Category: P-superfamily]] |
- | [[Category: | + | [[Category: Spasmodic]] |
- | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:33:29 2008'' | |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + |
Revision as of 17:33, 2 May 2008
Structure of a Novel P-Superfamily Spasmodic Conotoxin Reveals an Inhibitory Cystine Knot Motif
Overview
Conotoxin gm9a, a putative 27-residue polypeptide encoded by Conus gloriamaris, was recently identified as a homologue of the "spasmodic peptide", tx9a, isolated from the venom of the mollusk-hunting cone shell Conus textile (Lirazan, M. B., Hooper, D., Corpuz, G. P., Ramilo, C. A., Bandyopadhyay, P., Cruz, L. J., and Olivera, B. M. (2000) Biochemistry 39, 1583-1588). The C. gloriamaris spasmodic peptide has been synthesized, and the refolded polypeptide was shown to be biologically active using a mouse bioassay. The chemically synthesized gm9a elicited the same symptomatology described previously for natively folded tx9a, and gm9a and tx9a were of similar potency, implying that neither the two gamma-carboxyglutamate (Gla) residues found in tx9a (Ser(8) and Ala(13) in gm9a) nor Gly(1) (Ser(1) in gm9a) are crucial for biological activity. We have determined the three-dimensional structure of gm9a in aqueous solution and demonstrated that the molecule adopts the well known inhibitory cystine knot motif constrained by three disulfide bonds involving Cys(2)-Cys(16), Cys(6)-Cys(18) and Cys(12)-Cys(23). Based on the gm9a structure, the sites of Gla substitution in tx9a are in loops located on one surface of the molecule, which is unlikely to be involved directly in receptor binding. Because this is the first structure reported for a member of the newly defined P-superfamily conotoxins, a comparison has been made with structurally related conotoxins. This shows that the structural scaffold that characterizes the P-conotoxins has the greatest potential for exhibiting structural diversity among the robust inhibitory cystine knot-containing conotoxins, a finding that has implications for functional epitope mimicry and protein engineering.
About this Structure
1IXT is a Single protein structure. Full crystallographic information is available from OCA.
Reference
Structure of a novel P-superfamily spasmodic conotoxin reveals an inhibitory cystine knot motif., Miles LA, Dy CY, Nielsen J, Barnham KJ, Hinds MG, Olivera BM, Bulaj G, Norton RS, J Biol Chem. 2002 Nov 8;277(45):43033-40. Epub 2002 Aug 21. PMID:12193600 Page seeded by OCA on Fri May 2 20:33:29 2008
Categories: Single protein | Barnham, K J. | Bulaj, G. | Dy, C Y. | Hinds, M G. | Miles, L A. | Nielsen, J. | Norton, R S. | Olivera, B M. | Conotoxin | Conus gloriamari | Gm9 1 | Gm9a | Ick | Inhibitory cystine knot | P-superfamily | Spasmodic