A mannanase, ManA, of the polycentric anaerobic fungus<i>Orpinomyces</i>sp. strain PC-2 has carbohydrate binding and docking modules
Bibliographic record
Abstract
The anaerobic fungus Orpinomyces sp. strain PC-2 produces a broad spectrum of glycoside hydrolases, most of which are components of a high molecular mass cellulosomal complex. Here we report about a cDNA (manA) having 1924 bp isolated from the fungus and found to encode a polypeptide of 579 amino acid residues. Analysis of the deduced sequence revealed that it had a mannanase catalytic module, a family 1 carbohydrate-binding module, and a noncatalytic docking module. The catalytic module was homologous to aerobic fungal mannanases belonging to family 5 glycoside hydrolases, but unrelated to the previously isolated mannanases (family 26) of the anaerobic fungus Piromyces. No mannanase activity could be detected in Escherichia coli harboring a manA-containing plasmid. The manA was expressed in Saccharomyces cerevisiae and ManA was secreted into the culture medium in multiple forms. The purified extracellular heterologous mannanase hydrolyzed several types of mannan but lacked activity against cellulose, chitin, or beta-glucan. The enzyme had high specific activity toward locust bean mannan and an extremely broad pH profile. It was stable for several hours at 50 degrees C, but was rapidly inactivated at 60 degrees C. The carbohydrate-binding module of the Man A produced separately in E. coli bound preferably to insoluble lignocellulosic substrates, suggesting that it might play an important role in the complex enzyme system of the fungus for lignocellulose degradation.
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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".