Methyl-coenzyme M reductase, the rate-limiting enzyme in methanogenesis and anaerobic methane oxidation, is responsible for the biological production of more than 1 billion tons of methane per year. The mechanism of methane synthesis is thought to involve either methyl-nickel(III) or methyl radical/Ni(II)-thiolate intermediates. We employed transient kinetic, spectroscopic, and computational approaches to study the reaction between the active Ni(I) enzyme and substrates. Consistent with the methyl radical–based mechanism, there was no evidence for a methyl-Ni(III) species; furthermore, magnetic circular dichroism spectroscopy identified the Ni(II)-thiolate intermediate. Temperature-dependent transient kinetics also closely matched density functional theory predictions of the methyl radical mechanism.
U.S. scientists Jeffrey C. Hall, Michael Rosbash and Michael W. Young received the 2017 Nobel Prize in Physiology or Medicine today for their work uncovering the mechanisms behind the biological clock--present in the cells of all living things--called the circadian rhythm. This internal clock keeps the activity of everything, from single-celled organisms to humans, coordinated with the rotation of the planet and the cycles of day and night. It's the reason we're awake when it's light and sleep while it's dark (if we take care of ourselves, anyway). The work of the biological clock is obvious after cross-country or intercontinental flights, when jet lag leaves you tired and irritable. Crossing time zones throws your circadian rhythm out of sync with the environment, and it takes a few days for your cells to tick back into alignment.
Today, the Nobel committee kicked off its 2017 season by awarding the Nobel Prize in Physiology or Medicine to three scientists for their discoveries of the molecular mechanisms that control circadian rhythms. The Americans--Jeffrey C. Hall, Michael Rosbash, and Michael W. Young--used fruit flies to isolate a gene that dictates the biological clock ticking away inside all living organisms. Their work, though decades-old, has been crucial to understanding how the light emanating from screens can affect humans' well-being, as it takes people further and further out of sync with their internal timekeepers. Newer, flashier science had dominated predictions going into Monday's announcement. Crispr, the transformational gene-editing system being harnessed to make climate-resistant crops, more bountiful biofuels, and cutting edge therapies, was passed over this year.
Mathematical modeling has become increasingly adopted in analyzing the dynamics of biological systems at diverse length- and time-scales1,2,3,4,5,6. In each case, a model is typically formulated to account for the biological processes underlying the system dynamics of interest. When analyzing a gene circuit, the corresponding model often entails description of the gene expression; for a metabolic pathway, the corresponding model may describe the constituent enzymatic reactions; for an ecosystem, the corresponding model would describe growth, death, and movement of individual populations, which could in turn be influenced by other populations. We call these models mechanism-based models. Mechanism-based models are useful for testing our understanding of the systems of interest7,8,9,10,11,12,13,14.
The 2017 Nobel Prize in Physiology or Medicine was awarded to Americans Jeffrey C. Hall, Michael Rosbash and Michael W. Young for their discoveries of mechanisms for biological clocks, which enabled "a peek inside our biological clock and elucidate its inner workings." "Life on Earth is adapted to the rotation of our planet. For many years we have known that living organisms, including humans, have an internal, biological clock that helps them anticipate and adapt to the regular rhythm of the day. But how does this clock actually work? Jeffrey C. Hall, Michael Rosbash and Michael W. Young were able to peek inside our biological clock and elucidate its inner workings.