I haven't read all of these submissions. Are we talking about UV
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"
<[EMAIL PROTECTED]>
To: <CCP4BB@JISCMAIL.AC.UK>
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
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Robert M. Sweet E-Dress: [EMAIL PROTECTED]
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:
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