I think it was an N-terminal RGS-type His tag in 3O8Y (human lipoxygenase) that mediated crystal contacts with a symmetry related molecule. As I recall, this tag composed a B-strand that formed a nice interface with a "native" B-strand of the symmetry related molecule. Pretty cool...
-Brad On Wed, Jun 27, 2012 at 11:00 AM, Phoebe Rice <[email protected]> wrote: > With Flp recombinase - DNA complexes, a C-terminal His tag triggered a > different (but sadly not better) crystal form, and the His side chains > packed against the bases at the end of a neighboring DNA duplex. > > ===================================== > Phoebe A. Rice > Dept. of Biochemistry & Molecular Biology > The University of Chicago > phone 773 834 1723 > > http://bmb.bsd.uchicago.edu/Faculty_and_Research/01_Faculty/01_Faculty_Alphabetically.php?faculty_id=123 > http://www.rsc.org/shop/books/2008/9780854042722.asp > > > ---- Original message ---- > >Date: Wed, 27 Jun 2012 10:14:58 -0400 > >From: CCP4 bulletin board <[email protected]> (on behalf of "R. M. > Garavito" <[email protected]>) > >Subject: Re: [ccp4bb] The effect of His-tag location on crystallization > >To: [email protected] > > > > Most of the comments you will get will be anecdotal > > in that people will report the successful results > > and do not take the time or effort to characterize > > the less successful results. This often occurs > > because the tagged portion of the protein is most > > often disordered, even in the best crystals. Thus, > > other than saying "tagging on this end works, but > > tagging on that end doesn't," there is little more > > you can say. Each case will be different, and it is > > almost impossible to arrive at any generalized > > conclusion. > > We prefer C-terminal tagged proteins for a number of > > reasons, but if an N-terminally tagged protein > > crystallizes well, so be it. Of the dozens of N- > > and C-tagged protein structures we have solved in my > > lab and with collaborators, I have only seen one > > case of an ordered His-tag: the His residues had > > coordinated Cd ions, which proved essential for > > getting good crystals. However, beyond that there > > was not much more to say. > > For your protein and the resulting crystals, an > > N-terminally tagged protein crystallized well. > > Whether you can draw any more conclusions from > > these results depends on characterizing crystals of > > both N- and C-tagged proteins. Just assuming that > > the C-tagged protein is trying to crystallize in the > > same or related crystal form as the N-tagged protein > > is an unwarranted assumption without experimental > > evidence to back it up. That is why most groups > > just run with the winner. > > Cheers, > > Michael > > **************************************************************** > > R. Michael Garavito, Ph.D. > > Professor of Biochemistry & Molecular Biology > > 603 Wilson Rd., Rm. 513 > > Michigan State University > > East Lansing, MI 48824-1319 > > Office: (517) 355-9724 Lab: (517) 353-9125 > > FAX: (517) 353-9334 > > Email: [email protected] > > **************************************************************** > > On Jun 26, 2012, at 9:06 PM, weliu wrote: > > > > Dear all, > > > > We crystallized a protein and found that crystal > > quality greatly depended on the location of > > His-tag. When a His-tag was added at the > > C-terminus, only crystalline precipitate or > > spherical quasi crystals were grown. However, when > > the His-tag was moved to the N-terminus, single > > crystals were grown under a number of conditions, > > and the best one diffracted to 1.7 angstrom after > > optimization. I was wondering if there were > > published reports describing similar cases. > > > > Thank you in advance > > > > Wei Liu >
