Macromolecular Crystallization Facility

The 'Take Home' Message

Remember to leave everything in order for the next user!

-try to finish your data collection on time
-replenish liquid nitrogen supplies
-report any technical problems
-tidy up when you're finished

POLICY

Access

Researchers, staff or students wishing to access the MCF to conduct experiments should contact or have their supervisor contact the Facility Director. Consultation regarding the instruments, their uses and limitations may be offered. Those interested in discussing our services, user fees, or to schedule training or any services required should contact the Facility Manager

Reservations

Please coordinate your time with other users. Instrument time can be reserved on the sign-up board by the generator, or by contacting the Facility Manager . The level of usage of each instrument often varies, therefore you are advised to reserve the instrument at least 48 hours in advance. In order to allow other possible users to access the generator, please do not reserve it for more than 96 hours without interruption. Therefore, if you have been using the generator for 72 hours, do not start a new data collection-- instead, put your name at the bottom of the queue and let the next user go. If you reserve time and decide not to use it, you must cancel at least 24 hours in advance or you will be charged for instrument time.

Responsibilities of Users and Their Supervisors

Ensure there is sufficient liquid nitrogen for the next user: if in doubt, fill the second tank and leave it with the top on.

Fill in the log sheets in the binder. The generator log will be used to keep a record of usage. This record is critical for determining charges and for documenting usage for grant applications.

Record any problems/malfunctions in the RUH3R logbook.

Keep the x-ray room tidy for the next user. There are designated cupboards and drawers in the crystallization lab: please use these to store tools, cryo-caps, solutions and so on.

Data and Computer Maintenance

Process data as it is collected: This allows you to evaluate whether collection of a full dataset is worthwhile, and will also help you to optimize your data collection. For example, if the first 10 frames show that the mosaicity is 1.5-degrees, you may want to collect 2-degree oscillations rather than 1-degree oscillations. By processing "on the fly" you will also know exactly when you have a sufficiently complete/redundant dataset.

Remove frames from the Hercules computer: once your data collection has finished, transfer your frames to another computer or back them up onto a CD and then delete them from Hercules so that there is plenty of space for the next user.

Also from this web page:

Seeding Fun Facts

It is always better to have fewer, larger crystals than it is to have lots of tiny crystals.

Crystal seeds provide a template on which molecules may assemble to form a crystal with the same characteristics as the crystal from which it originated.

Seeding is a technique that helps to differentiate the process of nucleation from crystal growth-- When crystal seeds are added to a solution, the equilibrium shifts towards crystal formation and away from spontaneous nucleation.

Seeding Techniques

Macroseeding

This method involves growing a crystal in a highly saturated solution, then placing it in a less saturated solution where only growth of the crystal will occur.

Microseeding

Here, a few crystals are grown, then crushed, and then put into a solution that allows them to form into a few larger crystals. This involves a lot of experimentation with concentrations of solution components to get the desired number of crystals.