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Also, saying that you have a. 4.0 data without defining the beam line b. plates without defining the dimensions is of limited use to get feedback, in my view. If you got 4.0 data at home, and your plates are at least a couple of micron thick, one of the few modern micro crystal beam lines is very likely to yield excellent data for you. A. On Oct 16, 2012, at 9:37, Tim Gruene wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Dear Jahan, > > is your diffraction useless, or do you call 4A resolution useless? 4A is > not too bad and can be a start for structure determination while you are > waiting for better crystals. > > You give very little information about what you actually have done, and > if you search the bb-archive for "how to get better crystals" you can > probably make a book from the number of hits. > > If you got a large number of crystals while seeding, try harder - the > idea of micro seeding is to adjust the conditions below nucleation > concentration and seed there. Dilute your cat whisker further until you > have only very few seeds left (you may want to have a look at Fig. > 11.2.(a) on p. 63 of http://shelx.uni-ac.gwdg.de/~tg/thesis.pdf to get > an idea of the effect. > > If all else fails, you can also try restricted proteolysis, although I > would put this in "routine optimization methods" nowadays. > > Good luck, > Tim > > On 10/16/2012 12:01 AM, Jahan Alikhajeh wrote: >> Dear Friends, >> >> I am trying to crystalize a 70 kDa nasty protein but I got plate >> shape crystals with high mosaicity and useless diffraction (up to >> 4A). I tried to improve/optimize crystallization but either I got >> the same or nothing. I tried seeding but I had so many crystals >> without any improvement. Does anyone have better idea than routine >> optimization method in the lab? Thanks in advance. >> >> Jahan >> > > - -- > - -- > Dr Tim Gruene > Institut fuer anorganische Chemie > Tammannstr. 4 > D-37077 Goettingen > > GPG Key ID = A46BEE1A > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.12 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iD8DBQFQfQ68UxlJ7aRr7hoRAqsOAKCI5hIkO2VkI4EGEuQQfggWQASFqQCg2BHo > 6QaulOnNvPRocZ9r4BlQTVg= > =FM/p > -----END PGP SIGNATURE----- P please don't print this e-mail unless you really need to Anastassis (Tassos) Perrakis, Principal Investigator / Staff Member Department of Biochemistry (B8) Netherlands Cancer Institute, Dept. B8, 1066 CX Amsterdam, The Netherlands Tel: +31 20 512 1951 Fax: +31 20 512 1954 Mobile / SMS: +31 6 28 597791