Colicin Ia: Difference between revisions
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==Mechanism of uptake== | ==Mechanism of uptake== | ||
{{STRUCTURE_2hdi | PDB=2hdi | SCENE= | {{STRUCTURE_2hdi | PDB=2hdi | SCENE= }} | ||
<StructureSection load='2hdi' scene='Proteopedia:Main_page_develop/2q66_initial/3' size='500' side='right' caption='Structure showing the receptor binding domain of ColIa bound to its 70kDa outer membrane receptor (PDB entry [[2hdi]])'> | |||
| The structure shows the receptor binding domain of ColIa bound to its 70kDa outer membrane receptor, Cir (colicin i receptor) | |||
The flexible<ref> PMID: 15452437 </ref> N terminus of ColIa is responsible for binding to the colicin I receptor (Cir), which is a TonB-dependent transporter. Its normal function on ''E. coli'' is binding and transporting Fe<sup>3+</sup> across the outer membrane, but is parasitized by colicins for their transport and entry. When ColIa binds to Cir it results in a big conformational change, resulting in Cir being open and exposed extracellularly, with the ColIa R-domain positioned directly above it, bound at approximately 45<sup>o</sup> to the membrane. This results in the T and C domains remaining far above the membrane and away from the receptor. If Cir is indeed the molecule that transports ColIa across the membrane, this conformational change is that that would be required for penetration by the colicin<ref> PMID: 17464289 </ref>. | The flexible<ref> PMID: 15452437 </ref> N terminus of ColIa is responsible for binding to the colicin I receptor (Cir), which is a TonB-dependent transporter. Its normal function on ''E. coli'' is binding and transporting Fe<sup>3+</sup> across the outer membrane, but is parasitized by colicins for their transport and entry. When ColIa binds to Cir it results in a big conformational change, resulting in Cir being open and exposed extracellularly, with the ColIa R-domain positioned directly above it, bound at approximately 45<sup>o</sup> to the membrane. This results in the T and C domains remaining far above the membrane and away from the receptor. If Cir is indeed the molecule that transports ColIa across the membrane, this conformational change is that that would be required for penetration by the colicin<ref> PMID: 17464289 </ref>. | ||