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| | {{STRUCTURE_1y62| PDB=1y62 | SCENE= }} | | {{STRUCTURE_1y62| PDB=1y62 | SCENE= }} |
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| - | '''A 2.4 crystal structure of conkunitzin-S1, a novel Kunitz-fold cone snail neurotoxin.'''
| + | ===A 2.4 crystal structure of conkunitzin-S1, a novel Kunitz-fold cone snail neurotoxin.=== |
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| - | ==Overview==
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| - | Cone snails (Conus) are predatory marine mollusks that immobilize prey with venom containing 50-200 neurotoxic polypeptides. Most of these polypeptides are small disulfide-rich conotoxins that can be classified into families according to their respective ion-channel targets and patterns of cysteine-cysteine disulfides. Conkunitzin-S1, a potassium-channel pore-blocking toxin isolated from C. striatus venom, is a member of a newly defined conotoxin family with sequence homology to Kunitz-fold proteins such as alpha-dendrotoxin and bovine pancreatic trypsin inhibitor (BPTI). While conkunitzin-S1 and alpha-dendrotoxin are 42% identical in amino-acid sequence, conkunitzin-S1 has only four of the six cysteines normally found in Kunitz proteins. Here, the crystal structure of conkunitzin-S1 is reported. Conkunitzin-S1 adopts the canonical 3(10)-beta-beta-alpha Kunitz fold complete with additional distinguishing structural features including two completely buried water molecules. The crystal structure, although completely consistent with previously reported NMR distance restraints, provides a greater degree of precision for atomic coordinates, especially for S atoms and buried solvent molecules. The region normally cross-linked by cysteines II and IV in other Kunitz proteins retains a network of hydrogen bonds and van der Waals interactions comparable to those found in alpha-dendrotoxin and BPTI. In conkunitzin-S1, glycine occupies the sequence position normally reserved for cysteine II and the special steric properties of glycine allow additional van der Waals contacts with the glutamine residue substituting for cysteine IV. Evolution has thus defrayed the cost of losing a disulfide bond by augmenting and optimizing weaker yet nonetheless effective non-covalent interactions.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_16929098}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 16929098 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_16929098}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Beta sheet]] | | [[Category: Beta sheet]] |
| | [[Category: Kunitz fold]] | | [[Category: Kunitz fold]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 15:54:51 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 13:59:58 2008'' |
Revision as of 11:00, 27 July 2008
Template:STRUCTURE 1y62
A 2.4 crystal structure of conkunitzin-S1, a novel Kunitz-fold cone snail neurotoxin.
Template:ABSTRACT PUBMED 16929098
About this Structure
Full crystallographic information is available from OCA.
Reference
Structure of conkunitzin-S1, a neurotoxin and Kunitz-fold disulfide variant from cone snail., Dy CY, Buczek P, Imperial JS, Bulaj G, Horvath MP, Acta Crystallogr D Biol Crystallogr. 2006 Sep;62(Pt 9):980-90. Epub 2006, Aug 19. PMID:16929098
Page seeded by OCA on Sun Jul 27 13:59:58 2008
