Wiring Inducible Nitric Oxide Synthase
Notice bibliographique
Résumé
The "wires project" in the Gray group has been focused on characterizing short-lived intermediates of Fe heme enzyme catalytic cycles by designing and synthesizing photosensitizers (wires) that bind to the protein active site with high affinity. The heart of this thesis is on rhenium channel binding and ruthenium surface binding wires for inducible nitric oxide synthase (iNOS). Binding and inhibition studies were conducted, electron transfer (ET) kinetics were studied, and iNOS catalytic activity was assayed for nitric oxide (NO) production. Both channel and surface binding wires bind to iNOS with low micro molar affinity. Channel binding wires bind at the active site, closely interacting with the protoporphyrin IX iron heme (Fe heme). Characteristic spectral shifts of Fe heme perturbation were observed. The surface binding wires bind presumably at the hydrophobic patch of the oxygenase domain where the reductase domain was proposed to dock during electron transfer processes. The surface binding wire interacts closely with the Fe heme from the surface of the protein, but still close to where spectral shifts of the Fe heme were observed; however, the surface binding wire does not displace other channel binding wires, indicative of a second binding site. Upon photo-excitation of all rhenium wires, the resting state Fe(III) heme is reduced to Fe(II) heme in less than 10 ns, characterized by transient absorption spectroscopy. This ET rate is orders of magnitude faster than Fe(III) reduction by the reductase domain (kET = 1 s-1) under biological conditions. In some cases, the wires were observed to ligate the Fe(II), creating a six-coordinate Fe(II) complex. The fully coordinated Fe(II) species is prevented from binding oxygen, and the catalytic mechanism is terminated. Another electron cannot be injected, and there is no production of NO. In the cases where the wire was shorter, ligation of the Fe(II) species was not observed. The Fe(II) remains five-coordinate, leaving room for oxygen to bind and for the mechanism to continue. In this case, NOS catalytic activity was assayed for the production of NO by photo-excitation of the wires. Complications of photodecomposition of NO indicators presented a challenge in data analysis. It is possible that a very small amount of NO was produced by photo-excitation of the wire; unfortunately, nothing definitely can be concluded. A new method to assay for NOS catalytic activity was proposed. Both channel and surface binding wires led to many insights on substrate binding modes at the protein active site and on the surface; ET mechanisms were redefined, including amino acid radicals participating in electron transfer processes; and future directions for new wire were designed with hopes of accomplishing the long standing goal of characterizing high-valent Fe species.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,001 | 0,002 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».