Efficient generation of dendritic arrays of cross-linked hemoglobin: symmetry and redundancy
Bibliographic record
Abstract
Chemically connected protein arrays have significant diverse applications including the production of red cell substitutes, bioconjugate drug delivery, and protein therapies. In order to make materials of defined structure, there is a need for efficient and accessible reagents. While chemical cross-linking with a multi-subunit protein can be achieved in high yield, connecting proteins to one another in a dendritic assembly along with concurrent cross-linking has met with limited success. This has now been overcome through the design and implementation of a readily prepared reagent with added reaction sites that compensate for competing hydrolysis. N,N',N''-Tris[bis(sodium methyl phosphate)isophthalyl]-1,3,5-benzenetricarboxamide (1), a hexakis(methyl phosphate) isophthalyl trimesoyl tris-amide, was designed and synthesized in high yield in three stages from a reactive trimesoyl core. This material has three pairs of coplanar cross-linking reaction sites in a symmetrical array. The presence of three sets of sites greatly increases the probability that at least two sets will produce cross-links within hemoglobin tetramers (in competition with hydrolysis) and thereby connect two cross-linked tetramers at the same time. Reaction of 1 with deoxyhemoglobin at pH 8.5 gives a material that contains two cross-linked hemoglobin tetramers connected to one another and to a constituent alphabeta dimer. Products were characterized by SDS-PAGE, MS, enzyme digestion and HPLC. The isolated dendritic-hemoglobin with 2.5 tetrameric components has the same oxygen affinity as native hemoglobin (P50 = 5.0 torr) and retains cooperativity (n50 = 2.0). Analysis of circular dichroism spectra indicates that the assembly retains proper folding of the globin chains while the hemes are in an altered environment.
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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".