Mechanism of bacterial cell-surface attachment revealed by the structure of cellulosomal type II cohesin-dockerin complex
| Autor: | Jarrett J. Adams, Zongchao Jia, Steven P. Smith, Gour P. Pal |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Multidisciplinary Cohesin Cell Membrane Dockerin Biological Sciences Biology Crystallography X-Ray biology.organism_classification Cellulosome assembly Bacterial cell structure Protein Structure Tertiary Cellulosomes Clostridium thermocellum Cellulosome Cell membrane medicine.anatomical_structure Bacterial Proteins Biochemistry medicine Biophysics Anaerobic bacteria Protein Structure Quaternary Protein Binding |
| Zdroj: | Proceedings of the National Academy of Sciences. 103:305-310 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0507109103 |
| Popis: | 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 × 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|