3PEE

Structure of the C. difficile TcdB cysteine protease domain

Summary for 3PEE

• Entry DOI: 10.2210/pdb3pee/pdb
• Descriptor: Toxin B, CALCIUM ION, INOSITOL HEXAKISPHOSPHATE, ... (4 entities in total)
• Functional Keywords: clan cd cysteine protease, protease, inositol hexakisphosphate, toxin
• Biological source: Clostridium difficile
• Total number of polymer chains: 2
• Total formula weight: 59168.97

Authors

Lupardus, P.J.,Garcia, K.C. (deposition date: 2010-10-26, release date: 2011-02-16, Last modification date: 2023-09-06)

Primary citation

Shen, A.,Lupardus, P.J.,Gersch, M.M.,Puri, A.W.,Albrow, V.E.,Garcia, K.C.,Bogyo, M.
Defining an allosteric circuit in the cysteine protease domain of Clostridium difficile toxins.
Nat.Struct.Mol.Biol., 18:364-371, 2011

PubMed Abstract: An internal cysteine protease domain (CPD) autoproteolytically regulates Clostridium difficile glucosylating toxins by releasing a cytotoxic effector domain into target cells. CPD activity is itself allosterically regulated by the eukaryote-specific molecule inositol hexakisphosphate (InsP(6)). Although allostery controls the function of most proteins, the molecular details underlying this regulatory mechanism are often difficult to characterize. Here we use chemical probes to show that apo-CPD is in dynamic equilibrium between active and inactive states. InsP(6) markedly shifts this equilibrium toward an active conformer that is further restrained upon binding a suicide substrate. Structural analyses combined with systematic mutational and disulfide bond engineering studies show that residues within a β-hairpin region functionally couple the InsP(6)-binding site to the active site. Collectively, our results identify an allosteric circuit that allows bacterial virulence factors to sense and respond to the eukaryotic environment.

PubMed: 21317893
DOI: 10.1038/nsmb.1990

Experimental method

X-RAY DIFFRACTION (2.1 Å)