Thank you Patrick for your reply. As a note to others who might be interested, I found a few comments about scaling up interwoven in a long thread about which robot to buy that was posted on this bb a few years ago. The most salient link is probably:
http://www.mail-archive.com/ccp4bb@jiscmail.ac.uk/msg04387.html Also, I found Patrick has a more detailed description about what should be of primary consideration during scale-up written in the following post: http://groups.google.com/group/oryx_group/browse_thread/thread/b04a2d7736d5974d?pli=1 Regards On Wed, Aug 18, 2010 at 12:56 PM, Patrick Shaw Stewart < patr...@douglas.co.uk> wrote: > Hi Mo > > > > What you need to remember is that a relatively large amount of protein is > lost from smaller drops. The ratio of surface area to volume is greater. > With 100 + 100 nl drops about half of the protein is lost, either as skin on > the drops or on the plastic of the plate. > > > > So when you scale up you need to reduce the protein by about half. > (Another approach, suggested by Heather Ringrose, is to put extra protein > into the drops at the screening stage, e.g. 200 nl protein + 100 nl > reservoir solution. The hits found can usually be scaled up by dispensing 1 > + 1 microlitre drops.) > > > > This is counterintuitive because people expect the small drops to dry out > more quickly - so they expect, if anything, to get more precipitation in the > small drops. Instead they get precipitation when they scale up, assuming > they keep the ratio of protein to reservoir constant. > > > > > > It can also help, when you scale up, to increase the salt by 50 to 100% - > this is indicated by data mining but I’m not sure what the mechanism is > > > > Hope that’s helpful > > > > Patrick > > > > > > -- > > For information and discussion about protein crystallization and > automation, please join > > our bulletin board at http://groups-beta.google.com/group/oryx_group?hl=en > > > > patr...@douglas.co.uk Douglas Instruments Ltd. > > DouglasHouse, EastGarston, Hungerford, Berkshire, RG177HD, UK > > Directors: Peter Baldock, Patrick Shaw Stewart > > http://www.douglas.co.uk/ > > Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034 > > Regd. England 2177994, VAT Reg. GB 480 7371 36 > > > > *From:* CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] *On Behalf Of *Mo > Wong > *Sent:* 18 August 2010 16:18 > *To:* CCP4BB@JISCMAIL.AC.UK > *Subject:* [ccp4bb] Scaling up from an Intelliplate to Linbro Plate > > > > Hi all, > > I know scaling up from a hit found from a high throughput screen is an > empirical process, but does anyone have a good rule of thumb as a starting > point when it comes to scaling up from a hit observed in an Intelliplate to > a Linbro plate (i.e., change in volume ratios, amount to add to reservoir, > etc)? I've Googled around but haven't seen anything which either suggests I > shouldn't be asking this question, I've not looked hard enough, or it really > is a case of "try and see". > > Thanks >
