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Table 1 Kinetic parameters and the determined thermostability of sbAvds

From: Modification of the loops in the ligand-binding site turns avidin into a steroid-binding protein

Protein

Ligand

SPR

  

DSC

  
  

ka(1/Ms)

kd(1/s)

KD(M)

Tm(°C)

ΔTm(°C)

ΔH ×104 (cal/mol)

wtAvd

-

-

-

-

85.5

-

5.4

wtAvd

Btn

n.d.

n.d.

n.d.

123.2

37.7

12.8

wtAvd

Tes

-

-

no binding

86.2

0.7

5.6

sbAvd-1

-

-

-

-

80.6

-

5.2

sbAvd-1

Btn

4.2 × 105

5.6 × 10-4

1.4 × 10-9

83.2

2.6

6.4

sbAvd-1

Tes

1.0 × 103

9.5 × 10-3

9.0 × 10-6

81.5

0.9

5.7

sbAvd-2

-

-

-

-

82.5

-

4.6

sbAvd-2

Btn

1.0 × 103

6.8 × 10-4

6.6 × 10-7

83.0

0.5

4.2

sbAvd-2

Tes

813

8.5 × 10-3

1.1 × 10-5

83.1

0.6

4.8

  1. The kinetic parameters determined by SPR analysis. The biotin binding affinity of avidin is too high to be determined by SPR. The transition midpoint of thermal unfolding (Tm) and the calorimetric heat of unfolding were determined by DSC. Delta Tm represents the increase of Tm in the presence of 50 μM ligand.