Your question is about immobilized metal affinity chromatography (IMAC), often used to separate a protein expressed in the E. coli bacterium from other proteins made by it. The protein of interest is expressed with a histidine-containing affinity tag which binds to immobilized nickel or cobalt at neutral or basic pH. Immobilization is achieved by complexing to NTA (nitrilotriacetic acid) or IDA (iminodiacetic acid). For a discussion of the two ligands, see e.g. here.
There are a few proteins from E. coli (listed in this paper) that are known to bind along with the protein of interest. According to a post written by Damien Soghoian in 2004, nickel-NTA tends to bind stronger to histidine-tags while cobalt-NTA tends to bind more weakly, but this does not affect specificity (e.g. it would be across the board, not making the separation easier or harder).
Your question is about immobilized metal affinity chromatography (IMAC), often used to separate a protein expressed in the E. coli bacterium from other proteins made by it. The protein of interest is expressed with a histidine-containing affinity tag which binds to immobilized nickel or cobalt at neutral or basic pH. Immobilization is achieved by complexing to NTA (nitrilotriacetic acid) or IDA (iminodiacetic acid). For a discussion of the two ligands, see e.g. here.
There are a few proteins from E. coli (listed in this paper) that are known to bind along with the protein of interest. According to a post written by Damien Soghoian in 2004, nickel-NTA tends to bind stronger to histidine-tags while cobalt-NTA tends to bind more weakly, but this does not affect specificity (e.g. it would be across the board, not making the separation easier or harder).
Your question is about immobilized metal affinity chromatography (IMAC), often used to separate a protein expressed in the E. coli bacterium from other proteins made by it. The protein of interest is expressed with a histidine-containing affinity tag which binds to immobilized nickel or cobalt at neutral or basic pH. Immobilization is achieved by complexing to NTA (nitrilotriacetic acid) or IDA (iminodiacetic acid). For a discussion of the two ligands, see e.g. here.
There are a few proteins from E. coli (listed in this paper) that are known to bind along with the protein of interest. According to a post written by Damien Soghoian in 2004, nickel-NTA tends to bind stronger to histidine-tags while cobalt-NTA tends to bind more weakly, but this does not affect specificity (e.g. it would be across the board, not making the separation easier or harder).
Your question is about immobilized metal affinity chromatography (IMAC), often used to separate a protein expressed in the E. coli bacterium from other proteins made by it. The protein of interest is expressed with a histidine-containing affinity tag which binds to immobilized nickel or cobalt at neutral or basic pH. Immobilization is achieved by complexing to NTA (nitrilotriacetic acid) or IDA (iminodiacetic acid). For a discussion of the two ligands, see e.g. here.
There are a few proteins from E. coli (listed in this paper) that are known to bind along with the protein of interest. According to a post written by Damien Soghoian in 2004, nickel-NTA tends to bind stronger to histidine-tags while cobalt-NTA tends to bind more weakly, but this does not affect specificity (e.g. it would be across the board, not making the separation easier or harder).
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