Thesis final - after defense-7 - Jacobs University

Chapter 3
Figure 16 B: Represents the average polarity calculated by Zimmerman’s scale. The protein
average polarity values of the three ligands were correlated with the respective salt
concentrations where the fractions were collected. The error bars represent the standard
deviations of the average polarity values in each fraction. The statistical analysis revealed a
significant correlation (r 2 = 0.76; p < 0.0001).
This revealed that proteins with high polar residues in the protein sequence were eluted at
high salt concentrations at the beginning of the chromatography. In contrast, the proteins with
less polar residues in the protein sequence were eluted at the end of the chromatography at
low salt concentrations. The polar residues are usually the acidic and basic amino acids (Asp,
Asn, Glu, Lys, Arg, Gln). These amino acid residues are highly polar and occur on the surface
of protein at an aqueous interface. The non-polar residues such as (Ala, Val, Leu, Ile, Cys,
Met, Pro, Phe, and Trp) are usually found in the interior portion of the proteins (117). Based
on the abundance of these residues in a protein sequence, the polarity value has been assigned.
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