These authors contributed equally to this work.
N-terminal and C-terminal Domains of Arrestin Both Contribute in Binding to Rhodopsin†
Article first published online: 28 MAR 2007
Photochemistry and Photobiology
Volume 83, Issue 2, pages 385–393, March/April 2007
How to Cite
Skegro, D., Pulvermüller, A., Krafft, B., Granzin, J., Hofmann, K. P., Büldt, G. and Schlesinger, R. (2007), N-terminal and C-terminal Domains of Arrestin Both Contribute in Binding to Rhodopsin. Photochemistry and Photobiology, 83: 385–393. doi: 10.1562/2006-08-25-RA-1014
This paper is part of the Proceedings of the 12th International Conference on Retinal Proteins held at Awaji Island, Hyogo, Japan on 4–8 June 2006.
- Issue published online: 28 MAR 2007
- Article first published online: 28 MAR 2007
- Received 24 August 2006; accepted 20 November 2006; published online 28 November 2006; DOI: 10.1562/2006-08-25-RA-1014
Visual arrestin terminates the signal amplification cascade in photoreceptor cells by blocking the interaction of light activated phosphorylated rhodopsin with the G-protein transducin. Although crystal structures of arrestin and rhodopsin are available, it is still unknown how the complex of the two proteins is formed. To investigate the interaction sites of arrestin with rhodopsin various surface regions of recombinant arrestin were sterically blocked by different numbers of fluorophores (Alexa 633). The binding was recorded by time-resolved light scattering. To accomplish site-specific shielding of protein regions, in a first step all three wild-type cysteines were replaced by alanines. Nevertheless, regarding the magnitude and specificity of rhodopsin binding, the protein is still fully active. In a second step, new cysteines were introduced at selected sites to allow covalent binding of fluorophores. Upon attachment of Alexa 633 to the recombinant cysteines we observed that these bulky labels residing in the concave area of either the N- or the C-terminal domain do not perturb the activity of arrestin. By simultaneously modifying both domains with one Alexa 633 the binding capacity was reduced. The presence of two Alexa 633 molecules in each domain prevented binding of rhodopsin to arrestin. This observation indicates that both concave sites participate in binding.