Proteomic analysis of the CO<sub>2</sub>-concentrating mechanism in the open-ocean cyanobacterium <i>Synechococcus</i> WH8102
Bibliographic record
Abstract
The open-ocean cyanobacterium Synechococcus WH8102 has recently been sequenced, making high-throughput mass spectrometry(MS)-based proteomics studies possible. Here, we used 1D and 2D gel electrophoresis, matrix-assisted laser desorptionionization time-of-flight (MALDI-TOF) MS, and two-hybrid analysis to study the composition and protein interactions within the carboxysome, a protein-rich polyhedral body involved in the CO 2 -concentrating mechanism. We identified the Rubisco large and small subunits and CsoS1 and CsoS2 in the carboxysome-rich particulate fraction and thus conclude the proteins were solely associated with the carboxysome. We also determined that the carboxysome fraction contained numerous membrane-associated proteins, consistent with the presence of membrane contamination. Two-hybrid analysis indicated that CsoS2 and OrfA strongly interacted. They formed dimers and interacted with each other. To our knowledge, this is the first indication of OrfA being biochemically linked to the carboxysome. The ε-class carbonic anhydrase CsoS3 did not interact with other carboxysome components in a binary manner. CsoS3 may not interact, or it may only bind, in fully formed multiprotein complexes. Finally, growth rates and protein expression were unchanged between 100 and 750 µL·L 1 CO 2 .Key words: proteomics, CO 2 -concentrating mechanism, carboxysome, cyanobacteria, Synechococcus.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 | 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 teacher head, 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".