1e44

<table><tr><td colspan='2'>[[1e44]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E44 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1E44 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene></td></tr>

[[https://www.uniprot.org/uniprot/IMM3_ECOLX IMM3_ECOLX]] This protein inhibits the 16S RNA hydrolyzing activity of colicin E3 by binding with high affinity to the C-terminal catalytic domain of E3. This protein is able to protect a cell, which harbors the plasmid ColE3 against colicin E3. [[https://www.uniprot.org/uniprot/CEA3_ECOLX CEA3_ECOLX]] Inactivates ribosomes by hydrolyzing 16S RNA in 30S ribosomes at a specific site. Colicins are polypeptide toxins produced by and active against E.coli and closely related bacteria.

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== Publication Abstract from PubMed ==

BACKGROUND: The cytotoxicity of most ribonuclease E colicins towards Escherichia coli arises from their ability to specifically cleave between bases 1493 and 1494 of 16S ribosomal RNA. This activity is carried by the C-terminal domain of the colicin, an activity which if left unneutralised would lead to destruction of the producing cell. To combat this the host E. coli cell produces an inhibitor protein, the immunity protein, which forms a complex with the ribonuclease domain effectively suppressing its activity. RESULTS: We have solved the crystal structure of the cytotoxic domain of the ribonuclease colicin E3 in complex with its immunity protein, Im3. The structure of the ribonuclease domain, the first of its class, reveals a highly twisted central beta-sheet elaborated with a short N-terminal helix, the residues of which form a well-packed interface with the immunity protein. CONCLUSIONS: The structure of the ribonuclease domain of colicin E3 is novel and forms an interface with its inhibitor which is significantly different in character to that reported for the DNase colicin complexes with their immunity proteins. The structure also gives insight into the mode of action of this class of enzymatic colicins by allowing the identification of potentially catalytic residues. This in turn reveals that the inhibitor does not bind at the active site but rather at an adjacent site, leaving the catalytic centre exposed in a fashion similar to that observed for the DNase colicins. Thus, E. coli appears to have evolved similar methods for ensuring efficient inhibition of the potentially destructive effects of the two classes of enzymatic colicins.

Inhibition of a ribosome-inactivating ribonuclease: the crystal structure of the cytotoxic domain of colicin E3 in complex with its immunity protein.,Carr S, Walker D, James R, Kleanthous C, Hemmings AM Structure. 2000 Sep 15;8(9):949-60. PMID:10986462<ref>PMID:10986462</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Carr, S]]

[[Category: Hemmings, A M]]

[[Category: James, R]]

[[Category: Kleanthous, C]]

[[Category: Walker, D]]

[[Category: Toxin]]