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Re: [ccp4bb] UV light source for protein xtal detection |
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CCP4bb navigationCCP4bb <-- 2008 <-- May 2008 <-- 16 May 2008Subject: Re: UV light source for protein xtal detection From: Robert Sweet sweet {- at -} BNL {- dot -} GOV Date: 2008-05-16 illumination to create visible light? The work we intend to emulate is this: From Cipriani and Bourgeois's groups in Grenoble -- Acta Cryst. (2006). D62, 253-261. UV laser-excited fluorescence as a tool for the visualization of protein crystals mounted in loops. The 266nm light from a laser diode stimulates blue light from W residues. Bob On Fri, 16 May 2008, James Holton wrote: > 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" >> >> To: >> 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 >>> >>> > -- ========================================================================= Robert M. Sweet E-Dress: sweet@bnl.gov Group Leader, PXRR: Macromolecular ^ (that's L Crystallography Research Resource at NSLS not 1) http://px.nsls.bnl.gov/ Biology Dept Brookhaven Nat'l Lab. Phones: Upton, NY 11973 631 344 3401 (Office) U.S.A. 631 344 2741 (Facsimile) ========================================================================= CCP4bb navigationCCP4bb <-- 2008 <-- May 2008 <-- 16 May 2008 |
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