Structural determination and characterisation of the CYP105Q4 cytochrome P450 enzyme from Mycobacterium marinum.

The cytochrome P450 family of heme metalloenzymes (CYPs) catalyse important biological monooxygenation reactions. Mycobacterium marinum contains a gene encoding a CYP105Q4 enzyme of unknown function. Other members of the CYP105 CYP family have key roles in bacterial metabolism including the synthesis of secondary metabolites. We produced and purified the cytochrome P450 enzyme CYP105Q4 to enable its characterization. Several nitrogen-donor atom-containing ligands were found to bind to CYP105Q4 generating type II changes in the UV-vis absorbance spectrum. Based on the UV-vis absorbance spectra none of the potential substrate ligands we tested with CYP105Q4 were able to displace the sixth distal aqua ligand from the heme, though there was evidence for binding of oleic acid and amphotericin B. The crystal structure of CYP105Q4 in the substrate-free form was determined in an open conformation. A computational structural similarity search (Dali) was used to find the most closely related characterized relatives within the CYP105 family. The structure of CYP105Q4 enzyme was compared to the GfsF CYP enzyme from Streptomyces graminofaciens which is involved in the biosynthesis of a macrolide polyketide. This structural comparison to GfsF revealed conformational changes in the helices and loops near the entrance to the substrate access channel. A disordered B/C loop region, usually involved in substrate recognition, was also observed.

Computational methods meet in vitro techniques: A case study on fusaric acid and its possible detoxification through cytochrome P450 enzymes.

Mycotoxins are known environmental pollutants that may contaminate food and feed chains. Some mycotoxins are regulated in many countries to limit the trading of contaminated and harmful commodities. However, the so-called emerging mycotoxins are poorly understood and need to be investigated further. Fusaric acid is an emerging mycotoxin, noxious to plants and animals, but is known to be less toxic to plants when hydroxylated. The detoxification routes effective in animals have not been elucidated yet. In this context, this study integrated in silico and in vitro techniques to discover potential bioremediation routes to turn fusaric acid to its less toxic metabolites. The toxicodynamics of these forms in humans have also been addressed. An in silico screening process, followed by molecular docking and dynamics studies, identified CYP199A4 from the bacterium Rhodopseudomonas palustris HaA2 as a potential fusaric acid biotransforming enzyme. Its activity was confirmed in vitro. However, the effect of hydroxylation seemed to have a limited impact on the modelled toxicodynamics against human targets. This study represents a starting point to develop a hybrid in silico/in vitro pipeline to find bioremediation agents for other food, feed and environmental contaminants.

Review of the National Institute for Health and Care Excellence guidelines on chronic heart failure.

Guidelines are more accessible than ever and represent an important tool in clinical practice. The National Institute for Health and Care Excellence (NICE) has developed recommendations for heart failure diagnosis and management based not only on morbidity and mortality trial outcome data but also in-depth economic analysis, with a focus on generalisability to UK National Health Service clinical practice. There is broad consistency in structure and content between NICE guidelines and those produced by major cardiovascular organisations such as the American College of Cardiology/American Heart Association and the European Society of Cardiology. However, important differences do exist-largely attributable to publication timing-a factor that is enhanced by the rapid pace of heart failure research. This article reviews the most recent iteration of NICE chronic heart failure guidelines and compares them with major guidelines on an international scale. Variations in recommendations will be explored including implications for NICE guideline updates in the future.

Preconception counselling in women of reproductive age attending cardiology clinics in Scotland.

BACKGROUND: Guidelines for the management of cardiovascular disease (CVD) recommend preconception risk stratification and counselling in all women of childbearing age. We assessed the provision of preconception counselling (PCC) among women of reproductive age attending general cardiology outpatient clinics over a 12-month period in two large health boards in Scotland. METHODS AND RESULTS: Electronic health records were reviewed and data on patient demographics, cardiac diagnoses, medication use and the content of documented discussions regarding PCC were recorded. Women were classified according to the modified WHO (mWHO) risk stratification system. Among 1650 women with a cardiac diagnosis included (1 January 2016-31 December 2016), the mean age was 32.7±8.6 years, and 1574 (95.4%) attended a consultant-led clinic. A quarter (402, 24.4%) were prescribed at least one potentially fetotoxic cardiovascular medication. PCC was documented in 10.3% of women who were not pregnant or were unable to conceive at the time of review (159/1548). The distribution of mWHO classification, and proportion of patients within each mWHO category who received any form of PCC, was 15.0% and 6.0% in mWHO class I, 20.2% and 8.7% in mWHO class II, 22.6% and 10.6% in mWHO class II-III, 9.5% and 15.7% in mWHO class III and 3.9% and 19.7% in mWHO class IV. CONCLUSION: PCC is documented infrequently in women of reproductive age with CVD in the general outpatient setting. Education relating to the risks of cardiac disease in pregnancy for clinicians and patients, and tools to support healthcare providers in delivering PCC, is important.

Synthesis of steroidal inhibitors for Mycobacterium tuberculosis.

Oxidised derivatives of cholesterol have been shown to inhibit the growth of Mycobacterium tuberculosis (Mtb). The bacteriostatic activity of these compounds has been attributed to their inhibition of CYP125A1 and CYP142A1, two metabolically critical cytochromes P450 that initiate degradation of the sterol side chain. Here, we synthesise and characterise an extensive library of 28 cholesterol derivatives to develop a structure-activity relationship for this class of inhibitors. The candidate compounds were evaluated for MIC with virulent Mtb and in binding studies with CYP125A1 and CYP142A1 from Mtb.

NT-proBNP in patients presenting with myocardial infarction and non-obstructive coronary arteries without left ventricular systolic dysfunction.

Background: Myocardial infarction and non-obstructive coronary arteries (MINOCA) affects 1 in 9 patients with acute coronary syndrome and has no evidence-based therapy. NT-proBNP is an established biomarker associated with prognosis in heart failure and ischemic heart disease, although there is a paucity of data in patients with MINOCA. Methods: Prospective study of the diagnostic and clinical utility of measuring NT-proBNP in patients with MINOCA without left ventricular dysfunction or heart failure. Data collection was undertaken for patients with an initial diagnosis of MINOCA following urgent coronary angiography in the Golden Jubilee National Hospital (Clydebank, UK), a tertiary center. Demographics were collected in addition to left ventricular function by transthoracic echocardiography. NT-proBNP was measured from a clinically indicated blood sample obtained during routine venepuncture or within the catheter laboratory. Patient outcomes were collected prospectively by the clinical care team using digital follow-up. Results: Fifty-five patients with an initial diagnosis of MINOCA and left ventricular ejection fraction >40 % were included. NT-proBNP was available in 87 % of patients with a median value of 312 pg/mL (interquartile range: 107, 725). Post-discharge, 40 % (n = 24) of patients were readmitted to the hospital, including 15 with chest pain. NT-proBNP ≥125 pg/mL was associated with rehospitalization (P = 0.02). Two patients died and bleeding complications with concomitant antiplatelet therapy occurred in eight patients. Conclusion: NT-proBNP ≥ 125 pg/mL occurred in 72 % of patients presenting with MINOCA and an ejection fraction > 40% and was associated with rehospitalization.