1rh1

[[Image:1rh1.gif|left|200px]]<br /><applet load="1rh1" size="450" color="white" frame="true" align="right" spinBox="true"

caption="1rh1, resolution 2.5&Aring;" />

'''crystal structure of the cytotoxic bacterial protein colicin B at 2.5 A resolution'''<br />

==Overview==

Colicin B (55 kDa) is a cytotoxic protein that recognizes the outer, membrane transporter, FepA, as a receptor and, after gaining access to the, cytoplasmic membranes of sensitive Escherichia coli cells, forms a pore, that depletes the electrochemical potential of the membrane and ultimately, results in cell death. To begin to understand the series of dynamic, conformational changes that must occur as colicin B translocates from, outer membrane to cytoplasmic membrane, we report here the crystal, structure of colicin B at 2.5 A resolution. The crystal belongs to the, space group C2221 with unit cell dimensions a = 132.162 A, b = 138.167 A, c = 106.16 A. The overall structure of colicin B is dumbbell shaped., Unlike colicin Ia, the only other TonB-dependent colicin crystallized to, date, colicin B does not have clearly structurally delineated, receptor-binding and translocation domains. Instead, the unique N-terminal, lobe of the dumbbell contains both domains and consists of a large (290, residues), mostly beta-stranded structure with two short alpha-helices., This is followed by a single long ( approximately 74 A) helix that, connects the N-terminal domain to the C-terminal pore-forming domain, which is composed of 10 alpha-helices arranged in a bundle-type structure, similar to the pore-forming domains of other colicins. The TonB box, sequence at the N-terminus folds back to interact with the N-terminal lobe, of the dumbbell and leaves the flanking sequences highly disordered., Comparison of sequences among many colicins has allowed the identification, of a putative receptor-binding domain.

==About this Structure==

1RH1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1RH1 OCA].

 

Crystal structure of the cytotoxic bacterial protein colicin B at 2.5 A resolution., Hilsenbeck JL, Park H, Chen G, Youn B, Postle K, Kang C, Mol Microbiol. 2004 Feb;51(3):711-20. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=14731273 14731273]

[[Category: Single protein]]

[[Category: Chen, G.]]

[[Category: Hilsenbeck, J.L.]]

[[Category: Kang, C.]]

[[Category: Park, H.]]

[[Category: Postle, K.]]

[[Category: Youn, B.]]