Ni-NTA Superflow Columns
For gravity-flow purification of His-tagged proteins
Ni-NTA Superflow is available in convenient, pre-packed columns for purification of His-tagged proteins from manually prepared cleared lysates, which are applied to Ni-NTA Superflow Columns on a BioRobot vacuum manifold. His-tagged proteins are strongly and selectively bound to Ni-NTA.
The QIAexpress Ni-NTA Protein Purification System, including the Ni-NTA Superflow Columns, is based on the remarkable selectivity of patented Ni-NTA (nickel-nitrilotriacetic acid) resin for proteins containing an affinity tag of six or more histidine residues — the His tag. This technology allows one-step purification of almost any His-tagged protein from any expression system under native or denaturing conditions. NTA, which has four chelation sites for nickel ions, binds nickel more tightly than metal-chelating purification systems that only have three sites available for interaction with metal ions. The extra chelation site prevents nickel-ion leaching and results in a greater binding capacity and protein preparations with higher purity than those obtained using other metal-chelating purification systems. The QIAexpress system can be used to purify His-tagged proteins from any expression system including baculovirus, mammalian cells, yeast, and bacteria. See figure Ni NTA Superflow 96 Columns automated procedure.
The purification of His-tagged proteins consists of 4 stages: cell lysis, binding, washing, and elution (see figure Protein purification with the Ni-NTA Protein Purification System). Purification of recombinant proteins using the QIAexpress system does not depend on the 3-dimensional structure of the protein or His tag. This allows one-step protein purification under either native or denaturing conditions, from dilute solutions and crude lysates. Strong denaturants and detergents can be used for efficient solubilization and purification of receptors, membrane proteins, and proteins that form inclusion bodies. Reagents that allow efficient removal of nonspecifically binding contaminants can be included in wash buffers (see table). Purified proteins are eluted under mild conditions by adding 100–250 mM imidazole as competitor or by a reduction in pH.
The QIAexpress Ni-NTA Protein Purification System provides reliable, one-step purification of proteins suitable for any application, including:
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