Fig. 2.

Protein attachment methods. (A) Proteins can be attached randomly via different chemistries including aldehyde- and epoxy-treated slides that covalently attach protein by their primary amines or by adsorpition onto slides coated with nitrocellulose or acrylamide gel pads. (B) Proteins can be uniformly orientated onto slides coated with a ligand. For example, His6X-tagged proteins can be bound to nickel-derivatized slides and biotinylated proteins can be attached to streptavidin-coated slides. This leads to attachment through the tag and presumably orientates the protein away from the slide surface.