I also solved a structure on our home CuKa source by SIRAS with 20-60sec in 0.5-1M KI.
JPK ==============Original message text=============== On Tue, 25 Sep 2007 6:55:28 pm CDT James Whisstock wrote: Hi - sorry - rather than iodine I meant to say we had had success with Potassium Iodide (1M for 20 seconds)! Cheers James [EMAIL PROTECTED] wrote:> > Hi, > > I do not use their method as such - however, I love heavy atom soaks and > do them any time I can, so I've got very similar experiences in the past. > > Heavy atoms can bind very quickly even from quite dilute solutions - the > quickest I've ever soaked (and got useful data) was sodium > chloroplatinate > in under ten minutes at ~ 1mM concentration. The next quickest was > K2Pt(NO2)4 which tends to take between 10 minutes and 30 minutes, almost > regardless of the concentration. This is by far my favorite HAD reagent, > incidentally. > > In general my soaks are all less than one hour with a few exceptions, > such > as iodine [not iodide!] soak to iodinate tyrosines which is typically > better done during a day or so with very low amount of I2, via vapor > phase. > > Artem > >> Hi, >> >> I'd like to find out how successful the "quick soak" method for heavy >> atom derivatisation proposed by Radaev and Sun: >> >> Sun PD, Radaev S, Kattah M. Generating isomorphous heavy-atom >> derivatives by a quick-soak method. Part I: test cases. Acta Cryst. >> 2002. D58:1092-1098. >> >> has been in comparison to the "classical" method of longer soaks at >> low concentrations of heavy atom compound. The method was quite >> successful in our hands a few years ago but (fortunately?) it's >> becoming increasingly rare that we use heavy atoms. I understand that >> evidence will necessarily be anecdotal, but let's not let that stop >> us. >> >> Derek >> -- >> Derek Logan tel: +46 46 222 1443 >> Associate professor fax: +46 46 222 4692 >> Molecular Biophysics mob: +46 76 8585 707 >> Lund University >> Box 124, Lund, Sweden >> >> >> -- Professor James Whisstock NHMRC Principal Research Fellow / Monash University Senior Logan fellow Department of Biochemistry and Molecular Biology Monash University, Clayton Campus, PO Box 13d, VIC, 3800, Australia +613 9905 3747 (Phone) +613 9905 4699 (Fax) +61 418 170 585 (Mobile) ===========End of original message text=========== *********************************** Jacob Keller Northwestern University 6541 N. Francisco #3 Chicago IL 60645 (847)491-2438 [EMAIL PROTECTED] ***********************************
