Close

Search

Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
share
Email Facebook Twitter Google+ LinkedIn Comments

Laser Techniques Reveal Molecular Folding

Photonics Spectra
Mar 2004
Reporting in the Feb. 20 issue of Science, scientists in the Timothy S. Zwier group at Purdue University in West Lafayette, Ind., have described how they used spectroscopic methods based on stimulated emission pumping to probe the folding process of tryptamine, a close analogue of the neurotransmitter serotonin and of the amino acid tryptophan. They hope that the approaches will enable a better understanding of conformational dynamics in proteins.

In the techniques, a UV dye laser pump excites a single conformation of the molecule to the zero-point vibrational level of the first excited electronic state, and a similar dump laser stimulates it back into a specific vibrational level in the ground electronic state. The sample then is collisionally cooled, and a third UV dye laser determines into which conformational minimum the sample has fallen by laser-induced fluorescence.

Tryptamine, for example, has seven conformational minima that are separated from one another by energy barriers, indicated by the red "valleys" in the image. By tuning the dump laser, the energy thresholds for isomerization from one minimum into other minima can be determined with high accuracy, and the proper choice of dump wavelength enables the selective formation of certain conformations of the molecule over others.

amino acid tryptophanAs We Go To PressBreaking Newsemission pumpingneurotransmitter serotoninPresstime BulletinPurdue Universityspectroscopiclasers

Comments
Terms & Conditions Privacy Policy About Us Contact Us
back to top

Facebook Twitter Instagram LinkedIn YouTube RSS
©2018 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA, info@photonics.com
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.