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:[log in to unmask]] On Behalf Of
James Holton
Sent: Friday, May 16, 2008 10:48 AM
To: [log in to unmask]
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"
> <[log in to unmask]>
> To: <[log in to unmask]>
> 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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