Ni salt of dodecyl sulphate is not soluble. Therefore (at least in theory) SDS may leach the Ni out of the chelate and deposit it throughout the column in baby-blue soapy flecks. Having said that, I must add that if you have to use more than 0.1% SDS then you're dealing with a truly extreme case!
Arginine at high concentrations can interfere with the chelaiton - pretty much any amine and amino acid would do that in high enough amounts. I've used arginine with Ni-NTA and His-Select resins and it wasn't an issue but my concentrations were moderate (under 50 mM). For the same reason, high concentrations of TRIS are not recommended either. Artem -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Jose Antonio Cuesta-Seijo Sent: Friday, June 27, 2008 5:37 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Binding to Nickel in the presence of SDS or arginine Dear CCP4BBers, One of those questions regarding purification rather than crystallography: Reading the Qiagen manual for the Ni-NTA matrices, in the table of compatibility of reagents with Ni-NTA matrices, SDS is mentioned (only together with sarkosyl) as "Not recommended, but up to 0.3% has been used successfully in some cases". Google is failing me to find those cases, since pretty much every paper mentioning Ni binding also mentions SDS-PAGE. Also, arginine is mentioned just as "not recommended". Why are SDS and arginine "not recommended", what are the physical and chemical underlying problems? Can they be used at low concentration without damaging the matrix or abolishing binding? Which are the maximal concentrations people had success with? Thanks a lot, Jose Antonio Cuesta Seijo ************************************** Jose Antonio Cuesta-Seijo Cancer Genomics and Proteomics Ontario Cancer Institute, UHN MaRS TMDT Room 4-902M 101 College Street M5G 1L7 Toronto, ON, Canada Phone: (416)581-7544 Fax: (416)581-7562 email: [EMAIL PROTECTED] **************************************
