A Novel Monomodular and Multifunctional Processive β‐1,4‐Endoglucanase Has Been Identified and Characterized from Porcine Gut Microbiome
Bibliographic record
Abstract
Cellulose‐degrading enzymes play an important role in dietary fibre digestion of humans and animals, as well as in multiple industrial applications. Herein, a plasmid metagenomic expression library was constructed for mining cellulose‐degrading enzymes from the pig hindgut microbiota that was modulated by feeding a purified crystalline cellulose supplemented diet (Journal of Animal Science, 2012, 90 (Suppl. 4):400–402). One of the cellulase genes screened from this library was localized to a 2949‐base pair insert fragment p4818. Within the sequence preceding this enzyme‐coding region, ‐10 and ‐35 promoter elements were identified along with three transcription‐factor binding sites. The enzyme possesses a catalytic domain consistent with those of the glycoside hydrolase family 5 subfamily 2 (GH5_2), thus named as p4818Cel5_2A. The protein was overexpressed, purified, and characterized; and it displayed optimal enzymatic activity at pH 6.0 and 50 °C. The enzyme also exhibited resilience to trypsin digestion, where >70 % activity was retained after 6.0 h incubation with trypsin at 37 °C. p4818Cel5_2A exhibited a broad substrate profile with the highest specific activity towards β‐glucan, carboxymethyl cellulose (CMC), followed by hydroxyethyl‐cellulose and regenerated amorphous cellulose (RAC). The enzyme was also active on other substrates including crystalline cellulose substrates such as Avicel and Solkafloc, as well as the hemicelluloses of glucomannan and xyloglucan. Furthermore, based on viscosity and hydrolysis product analyses, the enzyme behaved like a typical endo‐β‐1,4‐glucanase, and displayed processivity towards RAC. In summary, p4818Cel5_2A exhibited novel enzyme properties for potential industrial applications. Support or Funding Information Related research activities have been supported by grants (to M.Z.F.) from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) New Directions & Alternative Renewable Fuels Research Program; and the University of Guelph Gryphon's LAAIR (Leading to Accelerated Adoption of Innovative Research) program. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".