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Table 3 Binding affinity of IgG for PAB variants

From: Engineered protein A ligands, derived from a histidine-scanning library, facilitate the affinity purification of IgG under mild acidic conditions

 

pH = 7.4

pH = 5.0

Protein

KD(×10−9) (M−1)

KDratio

KD(×10−9) (M−1)

KDratio

PAB01 (WT)

5.1 ± 3.2

-

7.6 ± 4.3

-

PAB02 (D36H)

33.6 ± 19.2

6.6

832 ± 443

110

PAB03 (Q9H, D36H)

288 ± 146

56

ND

-

PAB04 (Q10H, D36H)

6830 ± 3600

1300

ND

-

PAB05 (R27H, D36H)

80.7

16

2090

270

PAB06 (K35H, D36H)

550 ± 143

110

3860

510

PAB07 (Q9H)

13.9 ± 6.3

2.7

30.6

4

PAB08 (Q10H)

50.8 ± 20.5

10

951

120

PAB09 (R27H)

5.6 ± 1.3

1.1

7.0

0.92

PAB10 (Q32H)

2.8 ± 1.3

0.55

96.8

13

  1. The binding assay was performed under neutral (pH = 7.4) and acidic (pH = 5.0) conditions using SPR. The IgG was immobilized on the surface of a CM5 sensor chip (GE Healthcare).
  2. KD, equilibrium dissociation constant: KD ratio, (KD of histidine-substituted PAB variant)/(KD of Wild-type PAB): ND, not determined.
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Journal of Biological Engineering

ISSN: 1754-1611