Effects of Photosynthetic Reaction Center H Protein Domain Mutations on Photosynthetic Properties and Reaction Center Assembly in<i>Rhodobacter sphaeroides</i>
Bibliographic record
Abstract
Purple bacterial photosynthetic reaction center (RC) H proteins comprise three cellular domains: an 11 amino acid N-terminal sequence on the periplasmic side of the inner membrane; a single transmembrane alpha-helix; and a large C-terminal, globular cytoplasmic domain. We studied the roles of these domains in Rhodobacter sphaeroides RC function and assembly, using a mutagenesis approach that included domain swapping with Blastochloris viridis RC H segments and a periplasmic domain deletion. All mutations that affected photosynthesis reduced the amount of the RC complex. The RC H periplasmic domain is shown to be involved in the accumulation of the RC H protein in the cell membrane, while the transmembrane domain has an additional role in RC complex assembly, perhaps through interactions with RC M. The RC H cytoplasmic domain also functions in RC complex assembly. There is a correlation between the amounts of membrane-associated RC H and RC L, whereas RC M is found in the cell membrane independently of RC H and RC L. Furthermore, substantial amounts of RC M and RC L are found in the soluble fraction of cells only when RC H is present in the membrane. We suggest that RC M provides a nucleus for RC complex assembly, and that a RC H/M/L assemblage results in a cytoplasmic pool of soluble RC M and RC L proteins to provide precursors for maximal production of the RC complex.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 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".