Journal ArticleDOI
Kinetics, binding constant, and activation energy of the 48-kDa protein-rhodopsin complex by extra-metarhodopsin II.
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TLDR
It is found that the 48-kDa protein (or S-antigen 48k) of the rod photoreceptor enhances the light-induced formation of the photoproduct metarhodopsin II (MII) from prephosphorylated rhodops in a manner analogous to the known enhancement of MII (extra-MII).Abstract:
We have found that the 48-kDa protein (or S-antigen 48k) of the rod photoreceptor enhances the light-induced formation of the photoproduct metarhodopsin II (MII) from prephosphorylated rhodopsin. The effect is analogous to the known enhancement of MII (extra-MII) that results from selective interaction of MII with G-protein. We have determined some parameters of the MII-48k interaction by measuring the extra-MII absorption change induced by the 48-kDa protein. The amplitude saturation yields a dissociation constant for the MII-48k complex on the order of 50 nM. At the technical limit of these measurements, 13.7 degrees C and 12 microM 48-kDa protein, we find a rate of 2.3 s-1 for formation of the 48k-MII complex. Extrapolation of these values to cellular conditions yields an occupation time of phosphorylated MII by 48k less than 200 ms. This is short compared to estimated rates of phosphorylation. The temperature dependence of the MII-48k formation rate is very high (Q10 for 5 degrees C/15 degrees C = 9-10). The related Arrhenius activation energy (165 kJ mol-1) is correspondingly high and indicates a considerable transient chemical change during the binding process.read more
Citations
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The role of receptor kinases and arrestins in g protein–coupled receptor regulation
TL;DR: The role of GRKs and arrestins in regulating agonist-specific signaling and trafficking of GPRs is discussed and endocytosis is linked to this process.
Journal ArticleDOI
Dark adaptation and the retinoid cycle of vision.
Trevor D. Lamb,Edward N. Pugh +1 more
TL;DR: A mathematical model that successfully describes a wide range of results in human and other mammals is presented, showing that the time-course of human dark adaptation and pigment regeneration is determined by the local concentration of 11-cis retinal, and that after a large bleach the recovery is limited by the rate at which 11-Cis Retinal is delivered to opsin in the bleached rod outer segments.
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Adaptors for clathrin coats: structure and function.
TL;DR: The structure of clathrin adaptors is reviewed to establish the dynamic regulatable networks to drive vesicle genesis at the correct time and place in the cell.
Journal ArticleDOI
The structural basis of arrestin-mediated regulation of G-protein-coupled receptors
TL;DR: The elucidation of the structural basis of arrestin interactions with numerous non-receptor-binding partners is long overdue and will allow the construction of fully functional arrestins in which the ability to interact with individual partners is specifically disrupted or enhanced by targeted mutagenesis.
References
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Journal ArticleDOI
Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products.
Journal Article
Cleavage of structural proteins during the assemble of the head of bacterio-phage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products as mentioned in this paper.
Journal ArticleDOI
Cyclic GMP cascade of vision.
TL;DR: The coming together of electrophysiology, biochemistry, and molecular genetics affords new opportunities in unraveling the molecular mechanism of visual transduction, and the interplay of cGMP, calcium ion, and phosphoinositides in excitation and adaptation is delineated.
Journal ArticleDOI
Phosphodiesterase activation by photoexcited rhodopsin is quenched when rhodopsin is phosphorylated and binds the intrinsic 48-kDa protein of rod outer segments.
U. Wilden,S. W. Hall,H. Kühn +2 more
TL;DR: It is reported here that deactivation of PDEase in rod outer segment suspensions is highly enhanced by addition of ATP and purified 48-kDa protein, which is an intrinsic rodouter segment protein that is soluble in the dark but binds to photolyzed rhodopsin that has been phosphorylated by rhodopin kinase and ATP.
Journal ArticleDOI
Tautomeric Forms of Metarhodopsin
TL;DR: The present experiments show that metarhodopsin exists in two tautomeric forms, metar Rhodopsins I and II, with λmax 478 and 380 mµ, which has been confused earlier with the final mixture of all-trans retinal and opsin, which it resembles in spectrum.
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Phosphodiesterase activation by photoexcited rhodopsin is quenched when rhodopsin is phosphorylated and binds the intrinsic 48-kDa protein of rod outer segments.
U. Wilden,S. W. Hall,H. Kühn +2 more