 |
 |
Hi Jai,
I agree with what Pamela says here and want to reiterate that sometimes if you mount a needle longer than the loop itself, the outside part of the needle can
cause the part of the needle inside the loop to bend upon freezing, which can destroy or distort the lattice. Best to use a loop bigger than the needle, or just break it into pieces. Acupuncture needles are good for doing this.
Good luck!
Nicola
From: CCP4 bulletin board [mailto:[log in to unmask]]
On Behalf Of Pamela J Focia
Sent: Monday, September 26, 2016 7:42 PM
To: [log in to unmask]
Subject: Re: [ccp4bb] Problem in crystals
Hello Jai,
I worked with long needle crystals for many years. I found that it was perfectly okay if they broke, sometimes much better to use a part of a crystal than to try to harvest/loop them whole. I even sometimes broke them on purpose!
When you loop long needle crystals whole they are susceptible to being affected by forces and strain of the cryosolvent and an imperfectly flat loop, or, if you accidentally get part of the crystal on the fiber, it could bow the crystal.
Even when I was able to loop an intact crystal, I found that there were better parts of most of the crystals w.r.t. diffraction limit and quality, and usually had to search for the ‘sweet spot’ to get the best data from each crystal.
If you have not done so yet, I recommend trying part of a broken crystal in the beam and see what you get. You might be pleasantly surprised.
Good luck!
-pamela
On Sep 26, 2016, at 8:16 AM, Thomas, Leonard M. <[log in to unmask]> wrote:
As I tell all students and those new to mounting crystals. It just takes patience and practice. The litho loops from either Mitegen or Molecular Dimensions work pretty well also.
Leonard M. Thomas Ph.D.
Macromolecular Crystallography Laboratory
Oklahoma COBRE in Structural Biology
Price Family Foundation Institute of Structural Biology
Department of Chemistry and Biochemistry
University of Oklahoma
Stephenson Life Sciences Research Center
101 Stephenson Parkway
Norman, OK 73019
405-325-1126
[log in to unmask]
https://urldefense.proofpoint.com/v2/url?u=http-3A__barlywine.chem.ou.edu&d=CwIFAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=KaQsb7Eep6rBKq4kVaJGW9wZ0byweUXIhZVijB0mDhI&m=1N7gZN2A7aJUWiq2d5xOMqZ_AesLbYeA_xsecWE_qKs&s=0zDwkooKF0vZcDPN8g8C6exUAGGoAkhpg6GflSrliXM&e=
https://urldefense.proofpoint.com/v2/url?u=http-3A__structuralbiology.ou.edu&d=CwIFAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=KaQsb7Eep6rBKq4kVaJGW9wZ0byweUXIhZVijB0mDhI&m=1N7gZN2A7aJUWiq2d5xOMqZ_AesLbYeA_xsecWE_qKs&s=_MRbvTOUuhz08kDtMnug6YFKF4JPBiV3kli_NhSvsS0&e=
On Sep 26, 2016, at 7:25 AM, Bonsor, Daniel <[log in to unmask]> wrote: