Heterogeneity between Two α Subunits of α<sub>2</sub>β<sub>2</sub> Human Hemoglobin and O<sub>2</sub> Binding Properties: Raman, <sup>1</sup>H Nuclear Magnetic Resonance, and Terahertz Spectra
Bibliographic record
Abstract
Following a previous detailed investigation of the β subunit of α 2 β 2 human adult hemoglobin (Hb A), this study focuses on the α subunit by using three natural valency hybrid α(Fe 2+ -deoxy/O 2 )β(Fe 3+ ) hemoglobin M (Hb M) in which O 2 cannot bind to the β subunit: Hb M Hyde Park (β92His → Tyr), Hb M Saskatoon (β63His → Tyr), and Hb M Milwaukee (β67Val → Glu). In contrast with the β subunit that exhibited a clear correlation between O 2 affinity and Fe 2+ –His stretching frequencies, the Fe 2+ –His stretching mode of the α subunit gave two Raman bands only in the T quaternary structure. This means the presence of two tertiary structures in α subunits of the α 2 β 2 tetramer with T structure, and the two structures seemed to be nondynamical as judged from terahertz absorption spectra in the 5–30 cm –1 region of Hb M Milwaukee, α(Fe 2+ -deoxy)β(Fe 3+ ). This kind of heterogeneity of α subunits was noticed in the reported spectra of a metal hybrid Hb A like α(Fe 2+ -deoxy)β(Co 2+ ) and, therefore, seems to be universal among α subunits of Hb A. Unexpectedly, the two Fe–His frequencies were hardly changed with a large alteration of O 2 affinity by pH change, suggesting no correlation of frequency with O 2 affinity for the α subunit. Instead, a new Fe 2+ –His band corresponding to the R quaternary structure appeared at a higher frequency and was intensified as the O 2 affinity increased. The high-frequency counterpart was also observed for a partially O 2 -bound form, α(Fe 2+ -deoxy)α(Fe 2+ -O 2 )β(Fe 3+ )β(Fe 3+ ), of the present Hb M, consistent with our previous finding that binding of O 2 to one α subunit of T structure α 2 β 2 tetramer changes the other α subunit to the R structure.
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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) | 0.001 | 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".