Structural comparison of metarhodopsin II, metarhodopsin III, and opsin based on kinetic analysis of Fourier transform infrared difference spectra
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چکیده
منابع مشابه
Structural comparison of metarhodopsin II, metarhodopsin III, and opsin based on kinetic analysis of Fourier transform infrared difference spectra.
Fourier transform infrared difference spectra were measured at 30-s intervals after a complete bleach of rhodopsin (rho) samples at 20 degrees C and three different pH values. At each pH, all of the spectra could be fit globally to two exponential decay processes. Using a branched unimolecular kinetic model in which metarhodopsin II (meta II) is hydrolyzed to opsin and retinal both directly and...
متن کاملSignaling states of rhodopsin. Formation of the storage form, metarhodopsin III, from active metarhodopsin II.
Vertebrate rhodopsin consists of the apoprotein opsin and the chromophore 11-cis-retinal covalently linked via a protonated Schiff base. Upon photoisomerization of the chromophore to all-trans-retinal, the retinylidene linkage hydrolyzes, and all-trans-retinal dissociates from opsin. The pigment is eventually restored by recombining with enzymatically produced 11-cis-retinal. All-trans-retinal ...
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We have obtained room-temperature transient infrared difference spectra of the M412 photoproduct of bacteriorhodopsin (bR) by using a "rapid-sweep" Fourier-transform infrared (FT-IR) technique that permits the collection of an entire spectrum (extending from 1000 to 2000 cm-1 with 8-cm-1 resolution) in 5 ms. These spectra exhibit less than 10(-4) absorbance unit of noise, even utilizing wet sam...
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The equilibria between metarhodopsins I and II (MI and MII) and the binding of MII to retinal G protein (G) were investigated, using the dual wavelength absorbance response of rod disk membrane (RDM) suspensions to a series of small bleaches, together with a nonlinear least-squares fitting procedure that decouples the two reactions. This method has been subjected to a variety of theoretical and...
متن کاملHydrogen bonding changes of internal water molecules in rhodopsin during metarhodopsin I and metarhodopsin II formation.
Rhodopsin is a 7-helix, integral membrane protein found in the rod outer segments, which serves as the light receptor in vision. Light absorption by the retinylidene chromophore of rhodopsin triggers an 11-cis-->all-trans isomerization, followed by a series of protein conformational changes, which culminate in the binding and activation of the G-protein transducin by the metarhodopsin II (Meta ...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 1992
ISSN: 0006-3495
DOI: 10.1016/s0006-3495(92)81700-9