Histidine is the axial ligand to cytochrome alpha 3 in cytochrome c oxidase

The nitric oxide-bound complexes of reduced yeast cytochrome c oxidase incorporated with [1,3-15N2]histidine have been investigated by EPR spectroscopy. The results of this study have allowed the unambiguous identification of histidine as the endogenous axial ligand to cytochrome alpha 3

Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies

The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu{a3}+2 and breaks the antiferromagnetic couple by forming a cytochrome a3+3-Cu{a3}+2-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58% of one heme. The effect of N3- on the cytochrome a3+3-Cu{a3}+2-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a3+2 and Cu{a3}+2 is proposed-i.e., cytochrome a3+2-NO-Cu{a3}+2. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with |A{}| = 0.020 cm-1, indicating that the Cu{a3}+2 in the cytochrome a3+2-NO-Cu{a3}+2 complex is similar to a type 2 copper site

The nature of CuA in cytochrome c oxidase

The isolation and purification of yeast cytochrome c oxidase is described. Characterization of the purified protein indicates that it is spectroscopically identical with cytochrome c oxidase isolated from beef heart. Preparations of isotopically substituted yeast cytochrome c oxidase are obtained incorporating [1,3-15N2]histidine or [beta,beta- 2H2]cysteine. Electron paramagnetic resonance and electron nuclear double resonance spectra of the isotopically substituted proteins identify unambiguously at least 1 cysteine and 1 histidine as ligands to CuA and suggest that substantial spin density is delocalized onto a cysteine sulfur in the oxidized protein to render the site Cu(I)-S

Особливості планування інвестиційних проектів з відтворення виробничої потужності збиткових вуглевидобувних підприємств

Розкрито особливості планування інвестиційних проектів з відтворення виробничої потужності на збиткових вуглевидобувних підприємствах. Запропоновано алгоритм розрахунку ефективності інвестиційного проекту. Ключові слова: інвестиції, вугільна галузь, шахта, відтворення потужності, проект, очисний вибій, ефективність, собівартість, термін окупності, дисконтування.Раскрыты особенности планирования инвестиционных проектов по воспроизводству производственной мощности на убыточных угледобывающих предприятиях. Предложен алгоритм расчета эффективности инвестиционного проекта. Ключевые слова: инвестиции, угольная отрасль, шахта, воспроизводство мощности, проект, очистной забой, эффективность, себестоимость, срок окупаемости, дисконтирование.The planning of investment projects on reproduction of production capacity of unprofitable coal-mining enterprises is described. The algorithm for calculating the efficiency of the investment project is offered. Its economic efficiency has been proven. Keywords: investments, coal industry, mine, reproduction of capacity, project, stope, efficiency, prime price, period of recoupment, discounting

Factors Associated With Nonunion in Arthrodesis of the First Metatarsophalangeal Joint:A Multicenter Retrospective Cohort Study

BACKGROUND: Arthrodesis of the first metatarsophalangeal joint is the current treatment of choice for symptomatic advanced hallux rigidus and moderate-to-severe hallux valgus. There are different methods to perform arthrodesis, yet no consensus on the best approach. Therefore, this study aimed to determine the effects of preoperative and postoperative hallux valgus angle (HVA), joint preparation and fixation technique, and postoperative immobilization on the incidence of nonunion.METHODS: A retrospective multicenter cohort study was performed that included 794 patients. Univariate and multiple logistic regression was conducted to determine associations between joint preparation, fixation techniques, postoperative immobilization, weightbearing, and pre- and postoperative HVA with nonunion.RESULTS: Nonunion incidence was 15.2%, with 11.1% symptomatic and revised. Joint preparation using hand instruments (OR 3.75, CI 1.90-7.42) and convex/concave reamers (OR 2.80, CI 1.52-5.16) were associated with greater odds of a nonunion compared to planar cuts. Joint fixation with crossed screws was associated with greater odds of nonunion (OR 2.00, CI 1.11-3.42), as was greater preoperative HVA (OR 1.02, CI 1.00-1.03). However, the latter effect disappeared after inclusion of postoperative HVA in the model, with a small association identified between residual postoperative HVA and nonunion (OR 1.04, CI 1.01-1.08). Similarly, we found an association between odds of nonunion and higher body weight (OR 1.02, CI 1.01-1.04) but not of body mass index.CONCLUSION: Based on our results, first metatarsophalangeal joint arthrodesis with planar cuts and fixation with a plate and interfragmentary screw is associated with the lowest odds of resulting in a nonunion. Higher body weight and greater preoperative HVA were associated with slight increase in rates of nonunion. It is crucial to properly correct the hallux valgus deformity during surgery.LEVEL OF EVIDENCE: Level III, retrospective case control study.</p