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| | {{STRUCTURE_1qua| PDB=1qua | SCENE= }} | | {{STRUCTURE_1qua| PDB=1qua | SCENE= }} |
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| - | '''CRYSTAL STRUCTURE OF ACUTOLYSIN-C, A HEMORRHAGIC TOXIN FROM THE SNAKE VENOM OF AGKISTRODON ACUTUS, AT 2.2 A RESOLUTION'''
| + | ===CRYSTAL STRUCTURE OF ACUTOLYSIN-C, A HEMORRHAGIC TOXIN FROM THE SNAKE VENOM OF AGKISTRODON ACUTUS, AT 2.2 A RESOLUTION=== |
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| - | ==Overview==
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| - | The structure of acutolysin-C, a haemorrhagic zinc metalloproteinase from the venom of Agkistrodon acutus, has been analyzed and refined at 2.2 A resolution. The space group of the crystal is P2(1)2(1)2(1), with unit-cell dimensions a = 46.84, b = 49.52, c = 95.34 A. One molecule was found in each asymmetric unit. The phasing problem was solved by the molecular-replacement program AMoRe. Crystallographic refinement was performed using X-PLOR, leading to final R and free R factors of 0.176 and 0.272, respectively. The residue sequence of acutolysin-C was determined mainly by electron density. No density was found for the first residue at the N--terminus and the last two residues at the C-terminus, which was also the case for most other P-I class snake-venom metalloproteinases (SVMPs). Acutolysin-C has two highly conserved characteristic sequences His142-Glu143-X-X-His146-X-X-Gly149-X-X-His15 2 and Cys162-Ile163-Met164. The enzyme has three disulfide bridges: Cys117-Cys195, Cys157-Cys179 and Cys159-Cys162. The entire structure shows good agreement with that of other reported P-I class SVMPs and has two subdomains with a cleft in which one catalytic zinc ion is localized. However, the local conformation (especially the disulfide configurations), the coordination of the catalytic water molecules and some residue side chains differ compared with other P-I class SVMPs. The proteolytic activities of SVMPs are sensitive to the pH value. The molecular superpositions around the proteolytic active sites of all the P-I class SVMP crystal structures show that the distances between the zinc ion and its ligands are not correlated with the crystallization pH values, although the contact distances between the catalytic water molecule and the O atoms of the Glu143 carboxylate group in the neutral and weakly alkaline structures are shorter than those in weakly acidic structures, and the closer the crystallization pH value of one enzyme is to its optimal activity pH value, the shorter the contact distances. Overall, all P-I class SVMPs have similar conformations in the active-site cleft. The size of the active site is not correlated with the crystallization pH values or the proteolytic activities. The disulfide bridge Cys117-Cys195 is conserved in all crystal structures of P-I class SVMPs, whereas the conformation and number of disulfide bridges in the C-terminal subdomain differ. Acutolysin-C has no structural calcium ion, which may not affect the proteolytic activity or haemorrhagic activity directly. | + | The line below this paragraph, {{ABSTRACT_PUBMED_10531480}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 10531480 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_10531480}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Metalloprotease]] | | [[Category: Metalloprotease]] |
| | [[Category: Snake venom proteinase]] | | [[Category: Snake venom proteinase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:42:43 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 06:24:45 2008'' |
Revision as of 03:24, 29 July 2008
Template:STRUCTURE 1qua
CRYSTAL STRUCTURE OF ACUTOLYSIN-C, A HEMORRHAGIC TOXIN FROM THE SNAKE VENOM OF AGKISTRODON ACUTUS, AT 2.2 A RESOLUTION
Template:ABSTRACT PUBMED 10531480
About this Structure
1QUA is a Single protein structure of sequence from Deinagkistrodon acutus. Full crystallographic information is available from OCA.
Reference
Structure of acutolysin-C, a haemorrhagic toxin from the venom of Agkistrodon acutus, providing further evidence for the mechanism of the pH-dependent proteolytic reaction of zinc metalloproteinases., Zhu X, Teng M, Niu L, Acta Crystallogr D Biol Crystallogr. 1999 Nov;55(Pt 11):1834-41. PMID:10531480
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