1mdt: Difference between revisions
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[[ | ==THE REFINED STRUCTURE OF MONOMERIC DIPHTHERIA TOXIN AT 2.3 ANGSTROMS RESOLUTION== | ||
<StructureSection load='1mdt' size='340' side='right' caption='[[1mdt]], [[Resolution|resolution]] 2.30Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1mdt]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Corynephage_beta Corynephage beta]. The September 2005 RCSB PDB [http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Cholera Toxin'' by David S. Goodsell is [http://dx.doi.org/10.2210/rcsb_pdb/mom_2005_9 10.2210/rcsb_pdb/mom_2005_9]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MDT OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1MDT FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=APU:ADENYLYL-3-5-PHOSPHO-URIDINE-3-MONOPHOSPHATE'>APU</scene><br> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mdt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mdt OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1mdt RCSB], [http://www.ebi.ac.uk/pdbsum/1mdt PDBsum]</span></td></tr> | |||
<table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The structure of toxic monomeric diphtheria toxin (DT) was determined at 2.3 A resolution by molecular replacement based on the domain structures in dimeric DT and refined to an R factor of 20.7%. The model consists of 2 monomers in the asymmetric unit (1,046 amino acid residues), including 2 bound adenylyl 3'-5' uridine 3' monophosphate molecules and 396 water molecules. The structures of the 3 domains are virtually identical in monomeric and dimeric DT; however, monomeric DT is compact and globular as compared to the "open" monomer within dimeric DT (Bennett MJ, Choe S, Eisenberg D, 1994b, Protein Sci 3:0000-0000). Detailed differences between monomeric and dimeric DT are described, particularly (1) changes in main-chain conformations of 8 residues acting as a hinge to "open" or "close" the receptor-binding (R) domain, and (2) a possible receptor-docking site, a beta-hairpin loop protruding from the R domain containing residues that bind the cell-surface DT receptor. Based on the monomeric and dimeric DT crystal structures we have determined and the solution studies of others, we present a 5-step structure-based mechanism of intoxication: (1) proteolysis of a disulfide-linked surface loop (residues 186-201) between the catalytic (C) and transmembrane (T) domains; (2) binding of a beta-hairpin loop protruding from the R domain to the DT receptor, leading to receptor-mediated endocytosis; (3) low pH-triggered open monomer formation and exposure of apolar surfaces in the T domain, which insert into the endosomal membrane; (4) translocation of the C domain into the cytosol; and (5) catalysis by the C domain of ADP-ribosylation of elongation factor 2. | |||
Refined structure of monomeric diphtheria toxin at 2.3 A resolution.,Bennett MJ, Eisenberg D Protein Sci. 1994 Sep;3(9):1464-75. PMID:7833808<ref>PMID:7833808</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[Diphtheria toxin|Diphtheria toxin]] | |||
== | == References == | ||
[[ | <references/> | ||
__TOC__ | |||
== | </StructureSection> | ||
< | |||
[[Category: Cholera Toxin]] | [[Category: Cholera Toxin]] | ||
[[Category: Corynephage beta]] | [[Category: Corynephage beta]] | ||
