Erim Bešić

Sigma radicals in gamma-irradiated single crystals of 2-thiothymine

Thioanalogs of the nucleic-acid bases are known photosensitive probes and good traps of radiation energy. Radiation-induced sulfur-centered free radicals stabilized on the base thioanalogs molecules are of the cationic origin. Their electronic configuration is of the π type, unless an electron-donating group, like Cl−, is added to the sulfur atom, forming the σσ* “ three-electron” S∴Cl bond. The σ radical observed in irradiated 2-thiothymine is formed simply by deprotonation of the pristine cation radical. The 2σ character of the radical is determined from the nature of the g tensor and the A(14N) coupling tensor and their relation to the radical skeleton. The deprotonation of the cation radical takes place at N(3) rather than at N(1), generally observed in the irradiated pyrimidine natural bases and their other thioanalogs.

5-Methyl-2-thiouracil.

The molecular structure of the title compound, also known as 2-thiothymine [systematic name: 2,3-dihydro-5-methyl-2-thioxopyrimidin-4(1H)-one], C(5)H(6)N(2)OS, is similar to that of thymine, with only small changes in the ring structure, apart from a significant difference at the substitution site [S=C = 1.674 (1) A]. The molecules are connected by hydrogen bonds, with N-H.O = 2.755 (2) A and N-H.S = 3.352 (1) A. The hydrogen-bond network is different from that in thymine, since it involves all the donor and acceptor atoms.

Glycosylation Profile of Immunoglobulin G Is Cross-Sectionally Associated With Cardiovascular Disease Risk Score and Subclinical Atherosclerosis in Two Independent Cohorts

Rationale: One measure of protein glycosylation (GlycA) has been reported to predict higher cardiovascular risk by reflecting inflammatory pathways. Objective: The main objective of this study is to assess the role of a comprehensive panel of IgG glycosylation traits on traditional risk factors for cardiovascular disease and on presence of subclinical atherosclerosis in addition to GlycA. Methods and Results: We measured 76 IgG glycosylation traits in 2970 women (age range, 40–79 years) from the TwinsUK cohort and correlated it to their estimated 10-year atherosclerotic cardiovascular disease risk score and their carotid and femoral plaque measured by ultrasound imaging. Eight IgG glycan traits are associated with the 10-year atherosclerotic cardiovascular disease risk score after adjusting for multiple tests and for individual risk factors—5 with increased risk and 3 with decreased risk. These glycans replicated in 967 women from ORCADES cohort (Orkney Complex Disease Study), and 6 of them were also associated in 845 men. A linear combination of IgG glycans and GlycA is also associated with presence of carotid (odds ratio, 1.55; 95% confidence interval, 1.25–1.93; P=7.5×10-5) and femoral (odds ratio, 1.32; 95% confidence interval, 1.06–1.64; P=0.01) plaque in a subset of women with atherosclerosis data after adjustment for traditional risk factors. One specific glycosylation trait, GP18-the percentage of FA2BG2S1 glycan in total IgG glycans, was negatively correlated with very-low-density lipoprotein and triglyceride levels in serum and with presence of carotid plaque (odds ratio, 0.60; 95% confidence interval, 0.50–0.71; P=5×10-4). Conclusions: We find molecular pathways linking IgG to arterial lesion formation. Glycosylation traits are independently associated with subclinical atherosclerosis. One specific trait related to the sialylated N-glycan is negatively correlated with cardiovascular disease risk, very-low-density lipoprotein and triglyceride serum levels, and presence of carotid plaque.

Betainohydroxamic acid chloride.

The title compound, N-hydroxy-2-(trimethylammonio)acetamide chloride, C(5)H(13)N(2)O(2)(+).Cl(-), has been synthesized and structurally characterized. The structure consists of betainohydroxamic acid cations and Cl(-) anions linked by N-H.Cl and O-H.Cl hydrogen bonds into chains along [001]. It was found that the positive inductive effect of the charged N atom in close proximity to the hydroxamate carbonyl O atom has a negligible effect on the hydroxamic C-N bond length.