8U9O
Solution structure of RsgI9 CRE domain from C. thermocellum
Summary for 8U9O
| Entry DOI | 10.2210/pdb8u9o/pdb |
| NMR Information | BMRB: 52129 |
| Descriptor | Anti-sigma-I factor RsgI9 (2 entities in total) |
| Functional Keywords | rsgi, cellulosome, anti-sigma factor, auto-proteolysis, signaling protein |
| Biological source | Acetivibrio thermocellus DSM 1313 More |
| Total number of polymer chains | 2 |
| Total formula weight | 20037.56 |
| Authors | Takayesu, A.,Mahoney, B.J.,Clubb, R.T. (deposition date: 2023-09-19, release date: 2024-04-24, Last modification date: 2024-07-10) |
| Primary citation | Takayesu, A.,Mahoney, B.J.,Goring, A.K.,Jessup, T.,Ogorzalek Loo, R.R.,Loo, J.A.,Clubb, R.T. Insight into the autoproteolysis mechanism of the RsgI9 anti-sigma factor from Clostridium thermocellum. Proteins, 92:946-958, 2024 Cited by PubMed Abstract: Clostridium thermocellum is a potential microbial platform to convert abundant plant biomass to biofuels and other renewable chemicals. It efficiently degrades lignocellulosic biomass using a surface displayed cellulosome, a megadalton sized multienzyme containing complex. The enzymatic composition and architecture of the cellulosome is controlled by several transmembrane biomass-sensing RsgI-type anti-σ factors. Recent studies suggest that these factors transduce signals from the cell surface via a conserved RsgI extracellular (CRE) domain (also called a periplasmic domain) that undergoes autoproteolysis through an incompletely understood mechanism. Here we report the structure of the autoproteolyzed CRE domain from the C. thermocellum RsgI9 anti-σ factor, revealing that the cleaved fragments forming this domain associate to form a stable α/β/α sandwich fold. Based on AlphaFold2 modeling, molecular dynamics simulations, and tandem mass spectrometry, we propose that a conserved Asn-Pro bond in RsgI9 autoproteolyzes via a succinimide intermediate whose formation is promoted by a conserved hydrogen bond network holding the scissile peptide bond in a strained conformation. As other RsgI anti-σ factors share sequence homology to RsgI9, they likely autoproteolyze through a similar mechanism. PubMed: 38597224DOI: 10.1002/prot.26690 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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