Uncontrolled reaction of organic compounds with oxygen is easy: we call it fire. But nature often needs to do oxidations very specifically, adding oxygen to a particular carbon atom in a complicated molecule without disturbing anything else. Usually, this job falls to an enzyme called cytochrome P450.
Because cytochrome P450 can catalyze molecular oxidations with pinpoint accuracy, it has been called "nature's blowtorch," and its job is analogous to that of a welder doing a tricky repair in a highly flammable wooden house. It needs to do the repair without burning itself or the house.
Brandeis University researchers have been trying to understand the details of how P450 does this job so efficiently; that is, "burning" the right places in the target molecule (substrate) while not "burning down the house."
In new research online in the Cell Press journal Structure, chemistry graduate student Bo OuYang, along with fellow grad student Marina Dang and advisors Thomas and Susan Pochapsky, describe a new insight into how P450 works. The researchers discovered that the protein chain in P450 can change its structure by a 180 degree rotation around a single peptide bond. In one orientation, both oxygen and the molecule to be oxidized (substrate) can get in and out of the P450 active site, but the oxygen is not "activated," that is, it is not in a state to react with the substrate (or anything else, for that matter).
In the other orientation, however, the substrate is held tightly in the correct orientation for the oxidation, and the oxygen can be activated to do "the burn." The activated form of the molecule is generated by binding a helper protein, called Pdx, to the P450. This binding drives the reorientation around the peptide bond, and moves the P450 from the form in which substrate binds to the active form. After the reaction is finished, the Pdx falls off, the P450 moves back to the unactivated state, and the oxidized products are free to leave.
After another substrate molecule and oxygen move into the active site, the cycle can repeat. The reorientation of a single peptide bond, an event called an "isomerization," thus acts as a molecular switch, moving the P450 between safe and active forms while protecting the P450 and its environment from accidental oxidative damage.
Laura Gardner | EurekAlert!
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences