2B59

The type II cohesin dockerin complex

Summary for 2B59

• Entry DOI: 10.2210/pdb2b59/pdb
• Descriptor: COG1196: Chromosome segregation ATPases, Cellulosomal scaffolding protein A, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: protein-protein complex, cellulosome, ef hand, montreal-kingston bacterial structural genomics initiative, bsgi, structural genomics, hydrolase-structural protein complex, hydrolase/structural protein
• Biological source: Clostridium thermocellum; More
• Cellular location: Secreted: Q06851
• Total number of polymer chains: 2
• Total formula weight: 39466.57

Authors

Adams, J.J.,Smith, S.P.,Montreal-Kingston Bacterial Structural Genomics Initiative (BSGI) (deposition date: 2005-09-27, release date: 2005-10-11, Last modification date: 2024-02-14)

Primary citation

Adams, J.J.,Pal, G.,Jia, Z.,Smith, S.P.
Mechanism of bacterial cell-surface attachment revealed by the structure of cellulosomal type II cohesin-dockerin complex.
Proc.Natl.Acad.Sci.Usa, 103:305-310, 2006

PubMed Abstract: Bacterial cell-surface attachment of macromolecular complexes maintains the microorganism in close proximity to extracellular substrates and allows for optimal uptake of hydrolytic byproducts. The cellulosome is a large multienzyme complex used by many anaerobic bacteria for the efficient degradation of plant cell-wall polysaccharides. The mechanism of cellulosome retention to the bacterial cell surface involves a calcium-mediated protein-protein interaction between the dockerin (Doc) module from the cellulosomal scaffold and a cohesin (Coh) module of cell-surface proteins located within the proteoglycan layer. Here, we report the structure of an ultra-high-affinity (K(a) = 1.44 x 10(10) M(-1)) complex between type II Doc, together with its neighboring X module from the cellulosome scaffold of Clostridium thermocellum, and a type II Coh module associated with the bacterial cell surface. Identification of X module-Doc and X module-Coh contacts reveal roles for the X module in Doc stability and enhanced Coh recognition. This extremely tight interaction involves one face of the Coh and both helices of the Doc and comprises significant hydrophobic character and a complementary extensive hydrogen-bond network. This structure represents a unique mechanism for cell-surface attachment in anaerobic bacteria and provides a rationale for discriminating between type I and type II Coh modules.

PubMed: 16384918
DOI: 10.1073/pnas.0507109103

Experimental method

X-RAY DIFFRACTION (2.11 Å)