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SUMMARY:The role of impurities in protein crystallisation: advantages and 
 disadvantages - Professor Abel Moreno
DTSTART:20090211T101500Z
DTEND:20090211T110000Z
UID:TALK16531@talks.cam.ac.uk
CONTACT:Professor Sir Tom Blundell
DESCRIPTION:Purity is an important factor in producing good crystals. Macr
 omolecular contaminants and micro-heterogeneities that are present within 
 a protein batch poison the faces of growing crystals and alter the crystal
  parking. Although macromolecular purity is thought to be essential for th
 e growth of flawless protein crystals\, only a few studies have investiga
 ted how contaminants alter or can vary in some way the crystallisation pro
 cess\, and crystal quality. Likewise\, the outcome of a crystallisation pr
 ocess may vary with the crystallisation method. In this talk\, I will show
  some examples of how these two variables affect crystallogenesis: asparty
 l-tRNA synthetase from the eubacterium Thermus thermophilus\, cytochrome C
  from bovine’s heart and Ferritin from horse’s spleen and other protei
 ns. Minute amounts of protein impurities alter to different extents the gr
 owth of each crystal form of asparthyl-tRNA synthetase and\, they affect t
 he presence of the isoforms of high quality crystals of cytochrome C. I wi
 ll also discuss the role of additives (precipitant solutions) and crystall
 isation method for the control of crystal morphology of Ferritin. Finally 
 I will show that after removing the impurities\, the best crystals are onl
 y obtained when the crystallizing solution is either enclosed in capillari
 es or immobilised in agarose gel or controlling the kinetics by applying a
  direct current/voltage during the crystallisation process. In these two e
 nvironments convection is reduced compared to that existing in an unconstr
 ained solution\, and at the same time gel is working as a filter of impuri
 ties. In this seminar\, the advantages and disadvantages of having impurit
 ies\, mixture of precipitating solutions\, and the crystal growth methods 
 for applications in protein crystallisation for high quality crystal obtai
 ning\, are revised.
LOCATION:Seminar Room\, Sanger Building
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