| Autor: |
Hunt, D. M., Wilkie, S. E., Bowmaker, J. K., Poopalasundaram, S. |
| Předmět: |
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| Zdroj: |
Cellular & Molecular Life Sciences; Oct2001, Vol. 58 Issue 11, p1583-1598, 16p, 1 Black and White Photograph, 3 Diagrams, 4 Charts, 5 Graphs |
| Abstrakt: |
Sensitivity to ultraviolet light (UV) is achieved by photoreceptors in the eye that contain a class of visual pigments maximally sensitive to light at wavelengths <400 nm. It is widespread in the animal kingdom where it is used for mate choice, communication and foraging for food. UV sensitivity is not, however, a constant feature of the visual system, and in many vertebrate species, the UV-sensitive (UVS) pigment is replaced by a violet-sensitive (VS) pigment with maximal sensitivity between 410 and 435 nm. The role of protonation of the Schiff base-chromophore linkage and the mechanism for tuning of pigments into the UV is discussed in detail. Amino acid sequence analysis of vertebrate VS/UVS pigments indicates that the ancestral pigment was UVS, with loss of UV sensitivity occurring separately in mammals, amphibia and birds, and subsequently regained by a single amino acid substitution in certain bird species. In contrast, no loss of UV sensitivity has occurred in the UVS pigments of insects. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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