Vision

“I can make molecules sing”

Thu, 13 Nov 2008 07:22:02 -0600

This image was the first slide in my Pecha-Kucha, given October 13 2008 (see the Pecha-Kucha website) for Chicago Artists Month.

It shows the molecular structure of the amino acid tryptophan, but I’ve replaced the “H” symbols with opera singers to illustrate that they can make sounds when probed with an NMR spectrometer. I used opera singers because they’re easily classified by their vocal ranges, thus I could readily match them with appropriate atoms based on their resonance frequencies. The atoms with the highest-frequency resonances are depicted as sopranos (on the 6-membered aromatic ring), slightly lower ones as altos (the delta H on the 5-membered ring), middle frequencies as tenors (the alpha hydrogen), and lowest frequencies as baritones (beta hydrogens).

I like this piece because it imparts an emotional life to the atoms. Chemists refer all the time to atoms’ and molecules’ emotional states, usually to describe their tendencies to undergo chemical reaction. Some molecules and portions of molecules (functional groups) are “labile,” “recalcitrant,” “inert,” “active,” and “passive,” for instance. Their relationships to other molecules are described in terms of like and dislike: “hydrophilic,” “hydrophobic,” and “amphipathic” to name a few. So it seems natural to put faces on the atoms to satisfy the next stage in chemical anthropomorphism.

Tryptophan: Musical 1H NMR Spectrum

Thu, 13 Nov 2008 06:44:54 -0600

This is just one example of the many visual representations I’ve created to illustrate Audible NMR. It is totally normal for analytical scientists to acquire 1H NMR spectra that look like the one shown here, though I’ve colored the NMR peaks and normal spectra just use a black line. The standard way of representing such a spectrum is to describe its horizontal axis in units of “parts-per-million” (ppm), which is convenient for reasons explained thoroughly in basics NMR descriptions. I’ve replotted this spectrum in units of KHz to make the connection between these signals and audio frequencies (roughly 0.1 - 20 KHz). I’ve also mapped each nuclear resonance to a key on a standard 88-key keyboard (with additional keys in gray at the right to accommodate higher frequencies), and translated them into musical notes, plotted on a standard scale. The colors string together the connections of individual resonances in the spectrum, with their corresponding atoms, with their corresponding keys, and their corresponding notes.

Thus we enter a realm where molecules are described by music, where visual data become audible, and where these tiny tiny bits of stuff become tangible through the power of analytical chemistry.

“CANCER”

Fri, 24 Oct 2008 22:31:52 -0500

When I first saw this spectrum in the laboratory, I thought – and may have actually exclaimed – ‘Wow! This spectrum is gorgeous!’ Here, I’ve re-presented it using pressed flowers and nice paper to help you share the feeling of that moment.

The molecule Raf Kinase Inhibitor Protein (RKIP) plays critical roles in cellular signaling related to cancer, and is a focus for Prof. Marsha Rosner’s lab at the University of Chicago’s Ben May Cancer Institute. This work includes taking nuclear magnetic resonance (NMR) spectra of RKIP, such as the 2D 1H-15N heteronuclear single quantum coherence (HSQC) spectrum shown. The HSQC provides a fingerprint for the protein, where each crosspeak corresponds to one link in the protein’s chain. In our work, potential ligands (molecules that bind to the protein of interest) are added to the RKIP NMR sample, and we search for differences in the peaks’ positions for samples with and without ligand; if peaks corresponding to critical portions of RKIP shift position, then the ligand may be a lead for a drug – a potential cure for cancer!

“Epinephrine”

Fri, 24 Oct 2008 22:24:06 -0500

At the interface of art and science, we can explore concrete and abstract aspects of human emotions. Here we have a chemical with an emotional impact: adrenaline, which is at the chemical heart of lust and love, fight and flight. We are accustomed to encountering its beauty and even analyzing its effects as they relate to human behavior in art, music, literature, etc. But in this piece we treat the molecule’s spectral signature as an aesthetic object. We see first a symmetric arrangement of bleeding hearts - flowers pressed for this purpose - which we primarily view for its visual appeal. But the flowers are placed to re-create a 2D NMR spectrum taken of the molecule, thus integrating physical, analytical and metaphorical aspects of the heart.

The data compose a two-dimensional 1H-1H TOtal Correlation SpectroscopY (TOCSY) spectrum. In a TOCSY spectrum, each 1H atom exhibits a resonance on the diagonal (lower left to upper right). Pairs of 1H atoms can “talk” to one another (chemists say they are “scalar-coupled”) if they are connected by two or three covalent bonds; if two atoms are part of the same chatty network (A talks to B, B talks to C, and so on), they exhibit off-diagonal “cross-peaks” with one another. The traditionally-viewed TOCSY spectrum of epinephrine is shown here.