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| {{STRUCTURE_2j42| PDB=2j42 | SCENE= }} | | {{STRUCTURE_2j42| PDB=2j42 | SCENE= }} |
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| '''LOW QUALITY CRYSTAL STRUCTURE OF THE TRANSPORT COMPONENT C2-II OF THE C2-TOXIN FROM CLOSTRIDIUM BOTULINUM'''
| | ===LOW QUALITY CRYSTAL STRUCTURE OF THE TRANSPORT COMPONENT C2-II OF THE C2-TOXIN FROM CLOSTRIDIUM BOTULINUM=== |
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| ==Overview==
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| C2 toxin from Clostridium botulinum is composed of the enzyme component C2-I, which ADP-ribosylates actin, and the binding and translocation component C2-II, responsible for the interaction with eukaryotic cell receptors and the following endocytosis. Three C2-I crystal structures at resolutions of up to 1.75 A are presented together with a crystal structure of C2-II at an appreciably lower resolution and a model of the prepore formed by fragment C2-IIa. The C2-I structure was determined at pH 3.0 and at pH 6.1. The structural differences are small, indicating that C2-I does not unfold, even at a pH value as low as 3.0. The ADP-ribosyl transferase activity of C2-I was determined for alpha and beta/gamma-actin and related to that of Iota toxin and of mutant S361R of C2-I that introduced the arginine observed in Iota toxin. The substantial activity differences between alpha and beta/gamma-actin cannot be explained by the protein structures currently available. The structure of the transport component C2-II at pH 4.3 was established by molecular replacement using a model of the protective antigen of anthrax toxin at pH 6.0. The C-terminal receptor-binding domain of C2-II could not be located but was present in the crystals. It may be mobile. The relative orientation and positions of the four other domains of C2-II do not differ much from those of the protective antigen, indicating that no large conformational changes occur between pH 4.3 and pH 6.0. A model of the C2-IIa prepore structure was constructed based on the corresponding assembly of the protective antigen. It revealed a surprisingly large number of asparagine residues lining the pore. The interaction between C2-I and C2-IIa and the translocation of C2-I into the target cell are discussed.
| | The line below this paragraph, {{ABSTRACT_PUBMED_17027031}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 17027031 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_17027031}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Clostridium botulinum]] | | [[Category: Clostridium botulinum]] |
| [[Category: Toxin]] | | [[Category: Toxin]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 08:18:06 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 10:54:18 2008'' |
