3da3

<StructureSection load='3da3' size='340' side='right' caption='[[3da3]], [[Resolution|resolution]] 2.50&Aring;' scene=''>

<table><tr><td colspan='2'>[[3da3]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3DA3 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3DA3 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3da4|3da4]]</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3da3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3da3 OCA], [http://pdbe.org/3da3 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3da3 RCSB], [http://www.ebi.ac.uk/pdbsum/3da3 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3da3 ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/CEAM_ECOLX CEAM_ECOLX]] Colicins are polypeptide toxins produced by and active against E.coli and closely related bacteria. This is a calcium-requiring inhibitor for murein biosynthesis; it causes lysis of sensitive cells accompanied by murein degradation. The target site is possibly the cytoplasmic membrane.

Colicins are cytotoxic proteins secreted by certain strains of Escherichia coli. Colicin M is unique among these toxins in that it acts in the periplasm and specifically inhibits murein biosynthesis by hydrolyzing the pyrophosphate linkage between bactoprenol and the murein precursor. We crystallized colicin M and determined the structure at 1.7 A resolution using X-ray crystallography. The protein has a novel structure composed of three domains with distinct functions. The N-domain is a short random coil and contains the exposed TonB box. The central domain includes a hydrophobic -helix and binds presumably to the FhuA receptor. The C-domain is composed of a mixed -domain and forms the phosphatase. The architectures of the individual modules show no similarity to known structures. Amino acid replacements in previously isolated inactive colicin M mutants are located in the phosphatase domain, which contains a number of surface-exposed residues conserved in predicted bacteriocins of other bacteria. The novel phosphatase domain displays no sequence similarity to known phosphatases. The N-terminal and central domains are not conserved among bacteriocins, which likely reflect the distinct import proteins required for the uptake of the various bacteriocins. The homology pattern supports our previous proposal that colicins evolved by combination of distinct functional domains.

 

== References ==

[[Category: Bacillus coli migula 1895]]

[[Category: Albrecht, R]]

[[Category: Braun, V]]

[[Category: Romer, C]]

[[Category: Zeth, K]]

[[Category: Xray]]