Or similarly, the conditions in the crystallization drop (pH, ions, etc.) may kick out the ligand.
JPK On Fri, Jul 27, 2012 at 3:34 AM, <[email protected]> wrote: > ** > Dear Ni Shi, > Did you test a crystal, or uncrystallized protein? It may be that due to > crystal packing effects, only protein without ADP crystallizes. > > Best regards, > Herman > > ------------------------------ > *From:* CCP4 bulletin board [mailto:[email protected]] *On Behalf Of *Ni > shi > *Sent:* Friday, July 27, 2012 5:17 AM > *To:* [email protected] > *Subject:* [ccp4bb] ADP binds to the protein in solution but not show up > in the structure > > Dear CCP4ers, > > We have crystallized a kinase without adding any nuceotide, and the > structure does not show any eletron density at the ATP binding site. Yet > most of the bacterial-purified proteins of this family and also the > structures contains ADP . So we boiled the bacterial-purified protein, and > tested the ADP concentration with NADH-coupled ATPase Assay, Surprisingly, > the result shows that there is one molecule of ADP per protein. So why > would that happen? any suggestions are appreciated > > Best wishes > > Ni shi > -- > Ni shi > State Key Laboratory of Plant Phy > siology and biochemistry > College of Biological Sciences > China Agricultural University > No.2, Yuan Ming Yuan West Road > Haidian District, Beijing, China 100193 > Tel: +86-10-62732672 > E-mail: [email protected] <[email protected]> > <[email protected]> > > > -- ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program email: [email protected] *******************************************
