Nature’s blowtorch is an enzyme system that oxidizes toxins, drug molecules, and other noxious molecules found in the body ready for excretion. But, understanding exactly how this molecular machinery has been an ongoing research job for many years. Now, Ayyalusamy Ramamoorthy, Lucy Waskell, and Ulrich Dürr, at the University of Michigan, Ann Arbor, have turned to the powerful analytical technique of solid state NMR spectroscopy, to reveal important structural details about the enzyme without removing from its native site in the cell membrane.
The standard approach to working out a protein’s structure would be to extract it from the membrane, crystallize it, and then blast it with X-rays to get a clear picture of the position of every atom. Unfortunately, that does not show you the structure of the enzyme system while it is on the job. Instead, NMR bathes the sample in a strong magnetic field and then scans it with radio waves to see how the atoms respond. Depending on how the atoms in the enzyme are connected and to which and how many other atoms it is possible to build up a structural picture of the complete system.
Rams and his colleague have now found that nature’s blowtorch operates like an oxy-acetylene blowtorch. It is composed of two enzymes working together. The first enzyme, cytochrome P450, is the “acetylene”, which does the actual job of toxic breakdown, while the “oxy”, to stretch the metaphor, perhaps a little two far, is a second enzyme, cytochrome b5.
You can read more details in this week’s SpectroscopyNOW column from David Bradley together with news of the latest developments in using CDs and CD players as analytical tools for medical diagnostics and remote environmental testing. Team leader Ángel Maquieira of the Polytechnic University of Valencia, in Spain, told me that the The robustness of a CD is perfect for collecting environmental samples, it can be used offsite, immersed in a mixture of water, sample and reagent for several minutes, washed, and then stored in a pretty much standard CD box for taking back to the lab. Once back on site, the CDs can be played in a standard computer CD drive modified with the addition of a planar photodiode to detect the signal from any sample on the CD.
Also in this week’s issue researchers in California have developed a simple algorithm, which they have integrated into a download Excel spreadsheet that gives wine makers better control over the phenolic content of their product. The input data for the spreadsheet come from a computer-interfaced ultraviolet spectrometer, which can detect the different kinds of phenolics and tannins in the wine at different stages of the production process. You can read more on that here.
This issue, I also report on how detecting the differences between young and old hair using Raman spectroscopy is now possible, even if the hair is highly pigmented. You can find out more about that here.
Finally, another enzyme story, this time about PKA, protein kinase A, and the power of X-ray crystallography, which I disputed somewhat in the NMR item!