Carbon dioxide-catalyzed peroxynitrite reactivity - The resilience of the radical mechanism after two decades of research.

Peroxynitrite, ONOO, formed in tissues that are simultaneously generating NO and O, is widely regarded as a major contributor to oxidative stress. Many of the reactions involved are catalyzed by CO via formation of an unstable adduct, ONOOC(O)O, that undergoes O-O bond homolysis to produce NO and CO radicals, whose yields are equal at about 0.33 with respect to the ONOO reactant.

Trading in cooperativity for specificity to maintain uracil-free DNA.

Members of the dUTPase superfamily play an important role in the maintenance of the pyrimidine nucleotide balance and of genome integrity. dCTP deaminases and the bifunctional dCTP deaminase-dUTPases are cooperatively regulated by dTTP. However, the manifestation of allosteric behavior within the same trimeric protein architecture of dUTPases, the third member of the superfamily, has been a question of debate for decades.

S phase block following MEC1ATR inactivation occurs without severe dNTP depletion.

Inactivation of Mec1, the budding yeast ATR, results in a permanent S phase arrest followed by chromosome breakage and cell death during G2/M. The S phase arrest is proposed to stem from a defect in Mec1-mediated degradation of Sml1, a conserved inhibitor of ribonucleotide reductase (RNR), causing a severe depletion in cellular dNTP pools. Here, the casual link between the S phase arrest, Sml1, and dNTP-levels is examined using a temperature sensitive mec1 mutant.

Dynamic niche-specific adaptations in Neisseria meningitidis during infection.

Neisseria meningitidis is an opportunistic human pathogen that usually colonizes the nasopharyngeal mucosa asymptomatically. Upon invasion into the blood and central nervous system, this bacterium triggers a fulminant inflammatory reaction with the manifestations of septicemia and meningitis, causing high morbidity and mortality. To reveal the bacterial adaptations to specific and dynamic host environments, we performed a comprehensive proteomic survey of N.