We have a Honeybee system but do not usually use proteases. The biggest
problem we have found is that if anything precipitates in the tips they have to
be washed very well, usually with water or ethanol. The ceramic tip can be
washed using low concentrations of HCl (0.1M), which I believe would also
alleviate the protease problem.
Regina
________________________________
From: Horacio Botti <hbo...@pasteur.edu.uy>
To: CCP4BB@JISCMAIL.AC.UK
Sent: Tuesday, January 24, 2012 7:12 AM
Subject: [ccp4bb] Crystallization robot and trypsin
Dear all
We may use a Honeybee 963 robot to screen crystallization conditions
for trypsin-containing protein samples and we are worried about robot
contamination by residual protease.
How do you normally clean robots when using this kind of sample? Your
suggestions/recommendations will be appreciated. Thks!!
Horacio Botti
Unit of Protein Crystallography,
Institut Pasteur of Montevideo, Uruguay.
PS: below you have an old short CCP4 discussion:
[ccp4bb]: Crystallization robots and protease.
________________________________
* To: ccp...@dl.ac.uk
* Subject: [ccp4bb]: Crystallization robots and protease.
* From: Marc Graille <marc.grai...@ibbmc.u-psud.fr>
* Date: Mon, 19 Dec 2005 13:21:36 +0100
* Sender: owner-ccp...@dlmail1.dl.ac.uk
* User-agent: Debian Thunderbird 1.0.2 (X11/20050602)
________________________________
*** For details on how to be removed from this list visit the ***
*** CCP4 home page http://www.ccp4.ac.uk ***
Dear all,
I have a question regarding the use of robotics to screen for
crystallization conditions for proteases.
Does anyone have already used robots on proteases? If yes, have you
experienced any protease "contaminant" in the robot pipes, which could
have affected the results on other projects performed during the next
few days ??
I mean that we cannot exclude that a "contaminant" could digest the
protein we are working on and yield crystals of a fragment of the
studied protein.
We are hesitating in using our crystallization robots on proteases
as we are afraid to have some contaminant in the pipes that will
disturb all our future experiments!!!
Any advice about how to clean the robot syringes after use of proteases
are welcome!!!
Regards,
Marc
--
Marc Graille, PhD
Equipe de Genomique Structurale
Institut de Biochimie et de Biophysique Moleculaire et Cellulaire (IBBMC)
CNRS UMR8619 Bat 430 Universite Paris Sud
91405 Orsay Cedex
Tel: 0169155047
*** For details on how to be removed from this list visit the ***
*** CCP4 home page http://www.ccp4.ac.uk *** Dear Marc We recommend
cleaning dispensing tips with Hellmanex II from the German
company Hellma. It's for cleaning cuvettes. You can buy it from VWR
and others. Hellmanex is a mildly alkaline solution with surfactants etc. It
has no
enzymes in it, but you do need to flush with buffer to get rid of the
alkali. Previously, users reported that cleaning with methanol mixed with
concentrated HCl worked very well in extreme cases. Our robot, the Oryx, uses
only one tip for protein. This is
semi-disposable. Using one tip and touching off the drops has the great
advantage that virtually no protein is wasted, and drops as low as 20 nl
can be dispensed, even containing 50% glycerol! We recommend that users keep
tips that have been used for proteases
separately, and clean them after use. (The system comes with 8 tips and
replacements cost 45 USD.) Also we recommend that tips are thoroughly
cleaned once a fortnight for average use in any case. I hope this is helpful.
Sincerely Patrick -- patr...@douglas.co.uk Douglas Instruments Ltd.
DouglasHouse, EastGarston, Hungerford, Berkshire, RG177HD, UK
Directors: Peter Baldock, Patrick Shaw Stewart, James Smith
http://douglas.co.uk or http://www.douglasinstruments.com
Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034
