Molecular Characterization of Two Lysophospholipid:acyl-CoA Acyltransferases Belonging to the MBOAT Family in Nicotiana benthamiana
Bibliographic record
Abstract
In the remodeling pathway for the synthesis of phosphatidylcholine (PC), acyl-CoA-dependent lysophosphatidylcholine (lysoPC) acyltransferase (LPCAT) catalyzes the reacylation of lysoPC. A number of genes encoding LPCATs have been cloned and characterized from several plants in recent years. Using Arabidopsis and other plant LPCAT sequences to screen the genome database of Nicotiana benthamiana, we identified two cDNAs encoding the putative tobacco LPCATs (NbLPCAT1 and NbLPCAT2). Both of them were predicted to encode a protein of 463 amino acids with high similarity to LPCATs from other plants. Protein sequence features such as the presence of at least eight putative transmembrane regions, four highly conserved signature motifs and several invariant residues indicate that NbLPCATs belong to the membrane bound O-acyltransferase family. Lysophospholipid acyltransferase activity of NbLPCATs was confirmed by testing lyso-platelet-activating factor (lysoPAF) sensitivity through heterologous expression of each full-length cDNA in a yeast mutant Y02431 (lca1△) disrupted in endogenous LPCAT enzyme activity. Analysis of fatty acid profiles of phospholipids from the NbLPCAT-expressing yeast mutant Y02431 cultures supplemented with polyunsaturated fatty acids suggested more incorporation of linoleic acid (18:2n6, LA) and α-linolenic acid (18:3n3, ALA) into PC compared to yeast mutant harbouring empty vector. In vitro enzymatic assay demonstrated that NbLPCAT1had high lysoPC acyltransferase activity with a clear preference for α-linolenoyl-CoA (18:3), while NbLPCAT2 showed a high lysophosphatidic acid (lysoPA) acyltransferase activity towards α-linolenoyl-CoA and a weak lysoPC acyltransferase activity. Tissue-specific expression analysis showed a ubiquitous expression of NbLPCAT1 and NbLPCAT2 in roots, stems, leaves, flowers and seeds, and a strong expression in developing flowers. This is the first report on the cloning and characterization of lysophospholipid acyltransferases from N. benthamiana.
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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) | 0.000 | 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) | 0.000 | 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".