Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon.

摘要: Abstract At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 nocturnal Tokay gecko ( Gekko gekko ) and diurnal American chameleon Anolis carolinensis as chimeras between them. The reconstituted with 11- cis -retinal had wavelengths maximal absorption λ max 's) 467 496 nm, respectively. Chimeric pigment analyses indicated that 76–86%, 14–24%, 10% difference them could be explained by amino acid differences transmembrane (TM) helices I–IV, V–VII, interactions two segments, Evolutionary mutagenesis revealed 's diverged from each other only S49A (serine to alanine replacement at residue 49), S49F phenylalanine), L52M (leucine methionine), D83N (aspartic asparagine), M86T (methionine threonine), T97A (threonine alanine) but also replacements cause minor -shifts individually.