[ccp4bb] Quick soak method
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 Biophysicsmob: +46 76 8585 707 Lund University Box 124, Lund, Sweden
Re: [ccp4bb] Quick soak method
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 Biophysicsmob: +46 76 8585 707 Lund University Box 124, Lund, Sweden
Re: [ccp4bb] Quick soak method
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 Biophysicsmob: +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)
Re: [ccp4bb] Quick soak method
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 Biophysicsmob: +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] ***
