A His-tag is a sequence of approximately six histidine residues that is usually attached to either the N- or C- terminus of the protein being targeted (Loughran and Walls, 2010). The purification process usually uses immobilized metal affinity chromatography (IMAC) (Kaplow et al., 2009). In this technique, metal ions such as Ni2+ are immobilized on a resin that uses iminodiacetic acid as a chelating agent (Terpe, 2002). The His-tag binds to the metal ions in the column due to its high affinity for it (Terpe, 2002). Once the targeted proteins are bound to the column, the elution process must take place (Terpe, 2002). Imidazole is used in this method since it displaces the His-tag proteins and …show more content…
Roberts and colleagues were investigating how this virus was able to spread to neighboring cells (Roberts et al., 2014). While conducting their research, they figured out that the influenza A virus used an alternative pathway to infect cells through the use of GFP (Roberts et al., 2014). The GFP-tagged influenza A virus gave the researchers a visual of how the viral proteins moved from cell to cell in one direction through intracellular connections (Roberts et al., 2014). These intercellular connections required actin dynamics and the absence of microtubules in order to form (Roberts et al., 2014). This virus does not use primary mechanisms of spreading such as budding or the release of cell-free virions (Roberts et al.,