A green cone-like pigment in the 'blind' mole-rat Spalax ehrenbergi: functional expression and photochemical characterization.
The degenerate subcutaneous eye of the blind mole rat belonging to the Spalax ehrenbergi superspecies has been shown to contain a long wavelength sensitive (LWS) cone pigment. Baculovirus expression of this LWS pigment and subsequent IMAC purification yields a photosensitive protein, that according to absorbance maximum (530 +/- 2 nm), kinetics of late phototransitions, and transducin activation, has all characteristics of a functional green cone pigment. The absorbance spectrum of the Spalax pigment is strongly red-shifted relative to the very homologous mouse, rabbit and rat green cone pigments (508-510 nm). Also in contrast to the rodent pigments, the Spalax pigment exhibits anion-dependent spectral properties, displaying a 12 nm blue-shift upon substitution of chloride ions by nitrate ions. Finally, the slow part of the photocascade deviates in some aspects from that of sighted mammals. The possible relevance of these findings for the evolutionary adaptation of Spalax to a subterranean ecotope is discussed.
Janssen
Jannie W H
JW
Department of Biochemistry UMC-160, Nijmegen Center for Molecular Lift, Sciences, University of Nijmegen Medical School, PO Box 9101, Nijmegen, The Netherlands.
David-Gray
Zoë K
ZK
Bovee-Geurts
Petra H M
PH
Nevo
Eviatar
E
Foster
Russell G
RG
DeGrip
Willem J
WJ
D000818:Animals; D001766:Blindness; D005136:Eye Proteins / Q000737:chemistry* / Q000302:isolation & purification; D006801:Humans; D019577:Mole Rats; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000032:analysis; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012168:Retinal Pigments / Q000032:analysis*; D013053:Spectrophotometry
D005136:Eye Proteins; D011994:Recombinant Proteins; D012168:Retinal Pigments