Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
Synchrotrons are now producing thousands of macromolecular structures each year. The need for complementary techniques available on site has progressively emerged, either to assess the relevance of the structure of a protein or to monitor changes that may occur during X-ray diffraction data collection. Micro­spectro­photometers in the UV-visible absorbance or fluorescence mode have evolved over the past few decades to become the instruments of choice to perform such tests. Described here are recent improvements to the micro­spectro­photometer of the so-called Cryobench laboratory located at the European Synchrotron Radiation Facility, Grenoble, France. Optical and mechanical properties have been enhanced so as to record better spectra on smaller samples. A device has been implemented to measure the signal decay of fluorescent samples, either in the crystalline or in the solution state. Recording of the fluorescence lifetime in addition to the steady-state fluorescence emission spectrum allows precise monitoring of the fluorescent sample under study. The device consists of an adaptation of a commercially available time-correlated single-photon-counting (TCSPC) system. A method to record and analyze series of TCSPC histograms, e.g. collected as a function of temperature, is described. To validate the instruments, fluorescence lifetimes of fluorescent small molecules or proteins in the crystalline or solution state, at room and cryo temperatures, have been measured. Lifetimes of a number of fluorescent proteins of the GFP family were generally found to be shorter in crystals than in solution, and slightly longer at cryo temperatures than at ambient temperature. The possibility of performing fluorescence lifetime measurements on crystals at synchrotron facilities widens the variety of spectroscopic techniques complementing X-ray diffraction on macromolecular crystallography beamlines.

Subscribe to Journal of Applied Crystallography

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow J. Appl. Cryst.
Sign up for e-alerts
Follow J. Appl. Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds