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2k0d

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NMR structure of a mutant colicin e7 immunity protein im7 with an extended helix III

Structural highlights

2k0d is a 1 chain structure with sequence from Escherichia coli. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Solution NMR
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

IMM7_ECOLX This protein is able to protect a cell, which harbors the plasmid ColE7 encoding colicin E7, against colicin E7, it binds specifically to the DNase-type colicin and inhibits its bactericidal activity. Dimeric ImmE7 may possess a RNase activity that cleaves its own mRNA at a specific site and thus autoregulates translational expression of the downstream ceiE7 gene as well as degradation of the upstream ceaE7 mRNA.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The small (87-residue) alpha-helical protein Im7 (an inhibitor protein for colicin E7 that provides immunity to cells producing colicin E7) folds via a three-state mechanism involving an on-pathway intermediate. This kinetic intermediate contains three of four native helices that are oriented in a non-native manner so as to minimise exposed hydrophobic surface area at this point in folding. The short (6-residue) helix III has been shown to be unstructured in the intermediate ensemble and does not dock onto the developing hydrophobic core until after the rate-limiting transition state has been traversed. After helix III has docked, it adopts an alpha-helical secondary structure, and the side chains of residues within this region provide contacts that are crucial to native-state stability. In order to probe further the role of helix III in the folding mechanism of Im7, we created a variant that contains an eight-amino-acid polyalanine-like helix stabilised by a Glu-Arg salt bridge and an Asn-Pro-Gly capping motif, juxtaposed C-terminal to the natural 6-residue helix III. The effect of this insertion on the structure of the native protein and its folding mechanism were studied using NMR and varphi-value analysis, respectively. The results reveal a robust native structure that is not perturbed by the presence of the extended helix III. Mutational analysis performed to probe the folding mechanism of the redesigned protein revealed a conserved mechanism involving the canonical three-helical intermediate. The results suggest that folding via a three-helical species stabilised by both native and non-native interactions is an essential feature of Im7 folding, independent of the helical propensity of helix III.

Amino acid insertion reveals a necessary three-helical intermediate in the folding pathway of the colicin E7 immunity protein Im7.,Knowling SE, Figueiredo AM, Whittaker SB, Moore GR, Radford SE J Mol Biol. 2009 Oct 2;392(4):1074-86. Epub 2009 Aug 3. PMID:19651139^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Knowling SE, Figueiredo AM, Whittaker SB, Moore GR, Radford SE. Amino acid insertion reveals a necessary three-helical intermediate in the folding pathway of the colicin E7 immunity protein Im7. J Mol Biol. 2009 Oct 2;392(4):1074-86. Epub 2009 Aug 3. PMID:19651139 doi:10.1016/j.jmb.2009.07.085

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/2k0d"

@@ Line 1: / Line 1: @@
 ==NMR structure of a mutant colicin e7 immunity protein im7 with an extended helix III==
-<StructureSection load='2k0d' size='340' side='right'caption='[[2k0d]], [[NMR_Ensembles_of_Models | 30 NMR models]]' scene=''>
+<StructureSection load='2k0d' size='340' side='right'caption='[[2k0d]]' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[2k0d]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2K0D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2K0D FirstGlance]. <br>
-</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">imm, ceiE7 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])</td></tr>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
 <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2k0d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2k0d OCA], [https://pdbe.org/2k0d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2k0d RCSB], [https://www.ebi.ac.uk/pdbsum/2k0d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2k0d ProSAT]</span></td></tr>
 </table>
 == Function ==
-[[https://www.uniprot.org/uniprot/IMM7_ECOLX IMM7_ECOLX]] This protein is able to protect a cell, which harbors the plasmid ColE7 encoding colicin E7, against colicin E7, it binds specifically to the DNase-type colicin and inhibits its bactericidal activity. Dimeric ImmE7 may possess a RNase activity that cleaves its own mRNA at a specific site and thus autoregulates translational expression of the downstream ceiE7 gene as well as degradation of the upstream ceaE7 mRNA.
+[https://www.uniprot.org/uniprot/IMM7_ECOLX IMM7_ECOLX] This protein is able to protect a cell, which harbors the plasmid ColE7 encoding colicin E7, against colicin E7, it binds specifically to the DNase-type colicin and inhibits its bactericidal activity. Dimeric ImmE7 may possess a RNase activity that cleaves its own mRNA at a specific site and thus autoregulates translational expression of the downstream ceiE7 gene as well as degradation of the upstream ceaE7 mRNA.
 == Evolutionary Conservation ==
 [[Image:Consurf_key_small.gif|200px|right]]
@@ Line 37: / Line 37: @@
 [[Category: Escherichia coli]]
 [[Category: Large Structures]]
-[[Category: Figueiredo, A M]]
+[[Category: Figueiredo AM]]
-[[Category: Knowling, S E]]
+[[Category: Knowling SE]]
-[[Category: Moore, G R]]
+[[Category: Moore GR]]
-[[Category: Radford, S E]]
+[[Category: Radford SE]]
-[[Category: Spronk, C A]]
+[[Category: Spronk CA]]
-[[Category: Whittaker, S B]]
+[[Category: Whittaker SB]]
-[[Category: Protein]]
-[[Category: Toxin inhibitor]]

2k0d

From Proteopedia

Current revision

NMR structure of a mutant colicin e7 immunity protein im7 with an extended helix III

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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