There is a paper that may be of interest J.Applied Crystallography September 2005 by Christopher S. Lunde etal where they converted a light microscope to a UV for screening protein microcrystals.
Marie -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of James Holton Sent: Friday, May 16, 2008 10:48 AM To: [email protected] Subject: Re: [ccp4bb] UV light source for protein xtal detection It is not the light source that is expen$ive, but rather the microscope optics and the camera. Standard optical glass has a fairly high absorption in the UV. In most cases you can replace the glass with quartz by addig a "0" to the end of the price (before the decimal point). The camera is also a consideration because most CCD cameras are not very sensitive in the UV. If memory serves, Hamamatsu makes the UV sensitive camera for the Karima microscope, and that camera is a significant fraction of the price of the instrument. You can always compensate for cheap optics by using a brighter light source, but it is important to remember that UV is not just bad for your skin and eyes, but for other proteins as well. -James Li Zhijie wrote: > Hello, > > You may want to have a look at the UV LEDs, which should be the > cheapest option if you only need a specific wavelenth. > > I found this on google: http://www.3dzled.com/other.html. It seems > that they can make 280nM LEDs. It is interesting to note that they > also said these LEDs' "Wavelength tolerance is usually within +/- 5 > nm. For example 254 nm would be 249 nm to 259 nm and 415 nm would be > 410 nm to 415 nm or 415 nm to 420 nm" - apparently not as pure as > those generated by monochrometers, but should be good enough for > quatitating protein or exciting some fluorophores. I wonder if the > microscope makers would ever consider using these instead of those > multi-thousand $ light sources. > > One more thing: do not forget that 280nm UV is extremely harmful to > human eyes and skin. > > Zhijie Li > > ----- Original Message ----- From: "Torres-Larios Alfredo" > <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Wednesday, May 14, 2008 7:59 PM > Subject: [ccp4bb] UV light source for protein xtal detection > > >> Dear all, >> >> Here's another non CCP4 question: does anyone know a cheap >> alternative to set up a UV source at 280 nm? I'd really like to have >> one :), but I really don't have the $20K Dlls needed to buy a >> UV/white light source from the crystallographic vendors :(. >> >> Thanks so much in advance for your answers, Alfredo. >> >> Alfredo Torres-Larios, PhD >> Assistant Professor >> Instituto de Fisiologia Celular, UNAM. >> Ciudad Universitaria, Mexico >> >> ---------------------------------------------------------------- >> This message was sent using IMP, the Internet Messaging Program. >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Free Edition. >> Version: 7.5.446 / Virus Database: 269.23.16/1077 - Release Date: >> 5/11/2008 12:00 AM >> >>
