Hemoglobin binding and catalytic heme extraction by the IsdB receptor of <i>Staphylococcus aureus</i> (583.7)
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The Isd (Iron‐regulated surface determinant) system is a multi‐protein transporter that enables Staphylococcus aureus to take up iron from hemoglobin (Hb) during human infection. In this system, IsdB is a cell wall‐anchored surface protein that contains 2 NEAT domains and rapidly extracts heme from Hb. Using a series of recombinant IsdB constructs which included at least one NEAT domain, we demonstrated that both domains are required to bind Hb with high affinity (KD = 0.42 ± 0.05 μM) and to extract heme from Hb. Moreover, IsdB only extracted heme from oxidized metHb although it also bound oxyHb and the Hb‐CO complex. In a reconstituted model of the biological heme relay pathway, IsdB catalyzed heme transfer from metHb to IsdA with a Km for metHb of 0.75 ± 0.07 μN and a kcat of 0.22 ± 0.01 s‐1. The latter is consistent with the transfer of heme from metHb to IsdB as being the rate‐limiting step. Grant Funding Source : Supported by CIHR grant MOP‐49597
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.
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 | 0.000 | 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 it