1CII

COLICIN IA

Summary for 1CII

• Entry DOI: 10.2210/pdb1cii/pdb
• Descriptor: COLICIN IA (1 entity in total)
• Functional Keywords: colicin, bacteriocin, ion channel formation, transmembrane protein
• Biological source: Escherichia coli
• Cellular location: Cell membrane; Multi-pass membrane protein (Potential): P06716
• Total number of polymer chains: 1
• Total formula weight: 67036.27

Authors

Wiener, M.,Freymann, D.,Ghosh, P.,Stroud, R. (deposition date: 1997-01-08, release date: 1998-01-14, Last modification date: 2024-02-07)

Primary citation

Wiener, M.,Freymann, D.,Ghosh, P.,Stroud, R.M.
Crystal structure of colicin Ia.
Nature, 385:461-464, 1997

PubMed Abstract: The ion-channel forming colicins A, B, E1, Ia, Ib and N all kill bacterial cells selectively by co-opting bacterial active-transport pathways and forming voltage-gated ion conducting channels across the plasma membrane of the target bacterium. The crystal structure of colicin Ia reveals a molecule 210 A long with three distinct functional domains arranged along a backbone of two extraordinarily long alpha-helices. A central domain at the bend of the hairpin-like structure mediates specific recognition and binding to an outer-membrane receptor. A second domain mediates translocation across the outer membrane via the TonB transport pathway; the TonB-box recognition element of colicin Ia is on one side of three 80 A-long helices arranged as a helical sheet. A third domain is made up of 10 alpha-helices which form a voltage-activated and voltage-gated ion conducting channel across the plasma membrane of the target cell. The two 160 A-long alpha-helices that link the receptor-binding domain to the other domains enable the colicin Ia molecule to span the periplasmic space and contact both the outer and plasma membranes simultaneously during function.

PubMed: 9009197
DOI: 10.1038/385461a0

Experimental method

X-RAY DIFFRACTION (3 Å)