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:[log in to unmask]] On Behalf Of Jose
Antonio Cuesta-Seijo
Sent: Friday, June 27, 2008 5:37 PM
To: [log in to unmask]
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: [log in to unmask]
**************************************