Colicin E9: Difference between revisions
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{{STRUCTURE_2ivz | PDB=2ivz | SCENE= }} | {{STRUCTURE_2ivz | PDB=2ivz | SCENE= }} | ||
The primary receptor for colicin E9 is the vitamin B12 receptor, BtuB. It then requires the outer membrane porin OmpF - either the two form the functional receptor, or OmpF is recruited for subsequent translocation. The OmpF association with the BtuB-colicin complex is weak and transient. After the interaction with OmpF, colicin E9 requires the [[Tol]] system to pass across the periplasm<ref> PMID: 12804762 </ref>. The interaction with [[TolB]] is governed by a pentapeptide region in the N terminus, where ColE9 folds into a distorted hairpin within the six-bladed β-propeller of TolB<ref> PMID: 16894158 </ref>. The residues surrounding these (from 34 to 46) are unstructured and highly flexible, but the TolB box of 5 residues (DGSGW) is organised within this disordered domain<ref> PMID: 15452437 </ref>. Within this pentapeptide sequence, the 3 essential resides are D35, S37 and W39. Mutations in all but one of these residues leads to a reduced affinity of binding to TolB<ref> PMID: 16166536 </ref>. | The primary receptor for colicin E9 is the vitamin B12 receptor, BtuB. It then requires the outer membrane porin OmpF - either the two form the functional receptor, or OmpF is recruited for subsequent translocation. The OmpF association with the BtuB-colicin complex is weak and transient. After the interaction with OmpF, colicin E9 requires the [[Tol]] system to pass across the periplasm<ref> PMID: 12804762 </ref>. The interaction with [[TolB]] is governed by a pentapeptide region in the N terminus, where ColE9 folds into a distorted hairpin within the six-bladed β-propeller of TolB<ref> PMID: 16894158 </ref>. The residues surrounding these (from 34 to 46) are unstructured and highly flexible, but the TolB box of 5 residues (DGSGW) is organised within this disordered domain<ref> PMID: 15452437 </ref>. Within this pentapeptide sequence, the 3 essential resides are D35, S37 and W39. Mutations in all but one of these residues leads to a reduced affinity of binding to TolB<ref> PMID: 16166536 </ref>. Some regions in the entire site have reduced mobility relative to other regions, that form local hydrophobic clusters<ref> PMID: 15452437 </ref>. | ||
OmpF acts synergistically with BtuB to protect bacteria against the action of colicin E9. This could indicate that OmpF is a component of the receptor apparatus. Alternatively the role of OmpF could be more to do with translocation rather than receptor recognition | OmpF acts synergistically with BtuB to protect bacteria against the action of colicin E9. This could indicate that OmpF is a component of the receptor apparatus. Alternatively the role of OmpF could be more to do with translocation rather than receptor recognition | ||