How to get the magic triangle and the MAD triangle into your protein crystal.
The magic triangle 5-amino-2,4,6-triiodoisophthalic acid (I3C) and the MAD triangle 5-amino-2,4,6-tribromoisophthalic acid (B3C) are two representatives of a novel class of compounds that combine heavy atoms for experimental phasing with functional groups for protein interactions. These compounds are readily available and provide easy access to experimental phasing. The preparation of stock solutions and the incorporation of the compounds into protein crystals are discussed. As an example of incorporation via cocrystallization, the incorporation of B3C into bovine trypsin, resulting in a single site with high occupancy, is described.
Beck
Tobias
T
Department of Structural Chemistry, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany. tbeck@shelx.uni-ac.gwdg.de
da Cunha
Carlos Eduardo
CE
Sheldrick
George M
GM
D000818:Animals; D002417:Cattle; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D010795:Phthalic Acids / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D014283:Triiodobenzoic Acids / Q000737:chemistry*; D014357:Trypsin / Q000737:chemistry
C542184:5-amino-2,4,6-tribromoisophthalic acid; D010795:Phthalic Acids; D011506:Proteins; D014283:Triiodobenzoic Acids; C480700:5-amino-2,4,6-triiodoisophthalic acid; D014357:Trypsin