Conserved structural features anchor biofilm‐associated RTX –adhesins to the outer membrane of bacteria
| Autor: | Ilja K. Voets, Steven P. Smith, Shuaiqi Guo, Sean W. Phippen, David N. Langelaan, Peter L. Davies |
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| Přispěvatelé: | Macro-Organic Chemistry, Macromolecular and Organic Chemistry |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Protein Conformation 030106 microbiology Biochemistry Bacterial cell structure Surface-retention domains 03 medical and health sciences Protein structure Calcium/chemistry Periplasm/chemistry structural biology Magnesium Bacterial/chemistry Secretion Amino Acid Sequence Adhesins Bacterial Marinomonas Molecular Biology Conserved Sequence Bacterial adhesins Chemistry Marinomonas/chemistry C-terminus Magnesium/chemistry Computational Biology Cell Biology Periplasmic space Adhesins Bacterial/chemistry Adhesins Bacterial adhesin 030104 developmental biology Structural biology Biofilms Periplasm Proteolysis Biophysics Calcium Bacterial outer membrane Hydrophobic and Hydrophilic Interactions |
| Zdroj: | FEBS Journal, 285(10), 1812-1826. Wiley-Blackwell The FEBS Journal |
| ISSN: | 1742-4658 1742-464X |
| DOI: | 10.1111/febs.14441 |
| Popis: | Repeats-in-toxin (RTX) adhesins are present in many Gram-negative bacteria to facilitate biofilm formation. Previously, we reported that the 1.5-MDa RTX adhesin (MpIBP) from the Antarctic bacterium, Marinomonas primoryensis, is tethered to the bacterial cell surface via its N-terminal Region I (RI). Here, we show the detailed structural features of RI. It has an N-terminal periplasmic retention domain (RIN), a central domain (RIM) that can insert into the β-barrel of an outer-membrane pore protein during MpIBP secretion, and three extracellular domains at its C terminus (RIC) that transition the protein into the extender region (RII). RIN has a novel β-sandwich fold with a similar shape to βγ-crystallins and tryptophan RNA attenuation proteins. Because RIM undergoes fast and extensive degradation in vitro, its narrow cylindrical shape was rapidly measured by small-angle X-ray scattering before proteolysis could occur. The crystal structure of RIC comprises three tandem β-sandwich domains similar to those in RII, but increasing in their hydrophobicity with proximity to the outer membrane. In addition, the key Ca2+ ion that rigidifies the linkers between RII domains is not present between the first two of these RIC domains. This more flexible RI linker near the cell surface can act as a 'pivot' to help the 0.6-μm-long MpIBP sweep over larger volumes to find its binding partners. Since the physical features of RI are well conserved in the RTX adhesins of many Gram-negative bacteria, our detailed structural and bioinformatic analyses serve as a model for investigating the surface retention of biofilm-forming bacteria, including human pathogens. |
| Databáze: | OpenAIRE |
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