Licht-im-Terrarium: Literaturdatenbank
Licht-im-Terrarium: Literaturdatenbank |
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Takenaka, N., & Yokoyama, S. (2007). Mechanisms of spectral tuning in the rh2 pigments of tokay gecko and american chameleon. Gene, 399(1), 26–32. Added by: Sarina (2009-01-21 15:18:36) Last edited by: Sarina (2009-07-12 13:05:36) |
| Resource type: Journal Article DOI: 10.1016/j.gene.2007.04.036 BibTeX citation key: Takenaka2007 View all bibliographic details  |
Categories: Englisch = English Keywords: Echsen = Lizards, Farbsehen = Color Vision, Netzhaut = Retina, Sehvermögen = Visual Perception Creators: Takenaka, Yokoyama Collection: Gene |
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| Abstract |
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At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption ([lambda]max's) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76-86%, 14-24%, and 10% of the spectral difference between them could be explained by amino acid differences in transmembrane (TM) helices I-IV, V-VII, and amino acid interactions between the two segments, respectively. Evolutionary and mutagenesis analyses revealed that the [lambda]max's of the gecko and chameleon pigments diverged from each other not only by S49A (serine to alanine replacement at residue 49), S49F (serine to phenylalanine), L52M (leucine to methionine), D83N (aspartic acid to asparagine), M86T (methionine to threonine), and T97A (threonine to alanine) but also by other amino acid replacements that cause minor [lambda]max-shifts individually. Keywords: Visual pigments; Absoprtion spectra; Mutagenesis; Reptile Abbreviations: TM, transmembrane; λmax, wavelength of maximal absorption; RH2, rhodopsin-like; SWS1, short wavelength-sensitive type 1; MWS, middle wavelength-sensitive; LWS, long wavelength-sensitive. Added by: Sarina Last edited by: Sarina |