Skip to main content

Table 4 Summary of 9-AS binding parameters to Xenopus IRBP as determined by fluorescence spectroscopy. The binding of 9-AS to full-length IRBP and the four modules was determined by measuring the enhancement of 9-AS fluorescence and the quenching of protein endogenous fluorescence as a function of 9-AS concentration.

From: Module structure of interphotoreceptor retinoid-binding protein (IRBP) may provide bases for its complex role in the visual cycle – structure/function study of Xenopus IRBP

Protein

Binding sites (N) Kd (μM)

Enhancementa

Quenchingb

Full-length IRBP

N =

2.58 ± 0.17

0.18 ± 0.29

 

Kd =

0.28 ± 0.07

0.29 ± 0.11

Module 1

N =

2.55 ± 0.24

0.97 ± 0.19

 

Kd =

0.33 ± 0.15

0.42 ± 0.10

Module 2c

N =

1.49 ± 0.15

0.93 ± 0.06

 

Kd =

0.25 ± 0.08

0.13 ± 0.02

Module 3

N =

2.76 ± 0.09

1.06 ± 0.07

 

Kd =

0.16 ± 0.41

0.19 ± 0.03

Module 4

N =

2.23 ± 0.09

0.30 ± 0.09

 

Kd =

0.082 ± 0.037

0.16 ± 0.04

  1. aMonitored at 440 nm upon excitation at 360 nm.
  2. bMonitored at 340 nm upon excitation at 280 nm.
  3. cModule 2 data from Loew et al. Exp Eye Res. 2001, 73:257–264.
Back to article page

BMC Biochemistry

ISSN: 1471-2091

Contact us