Journal article
Probing functional interfaces of rod PDE γ-subunit using scanning fluorescent labeling
Cell biochemistry and biophysics, Vol.28(2), pp.115-133
06/1998
DOI: 10.1007/BF02737808
PMID: 9515163
Abstract
In the dark, the activity of the rod cGMP phosphodiesterase (PDE) catalytic α- and β-subunits (Pαβ) is inhibited by two γ-subunits (Pγ). On light stimulation of the photoreceptor cells, the GTP-bound α-subunit of visual G-protein transducin (GtaGTP) displaces the Pγ-subunits from their inhibitory sites on Pαβ, leading to the effector enzyme activation. We designed a number of Pγ mutants, each with a single cysteine residue evenly distributed at a different position along the Pγ polypeptide chain. These cysteine residues served as sites for the introduction of the environmentally sensitive fluorescent probe, 3-(bromoacetyl)-7-diethyl aminocoumarin (BC). Analysis of the interactions of Pαβ and Gta with the fluorescently labeled Pγ mutants suggests two distinct functional interfaces of Pγ. The Pαβ/Pγ interface is formed essentially by the C-terminus of Pγ and by the N-terminal portion of the Pγ polycationic region, Pγ-24-45, whereas the Pγ/Gta interface includes the C-terminal portion of Pγ-24-45 and the region surrounding Pγ Cys68. Such functional organization of Pγ may represent an important element for the PDE activation mechanism during transduction of visual signals.
Details
- Title: Subtitle
- Probing functional interfaces of rod PDE γ-subunit using scanning fluorescent labeling
- Creators
- Alexey Granovsky - Department of Physiology and Biophysics University of Iowa College of Medicine 52242 Iowa City IARandall McEntaffer - Department of Physiology and Biophysics University of Iowa College of Medicine 52242 Iowa City IANikolai Artemyev - Department of Physiology and Biophysics University of Iowa College of Medicine 52242 Iowa City IA
- Resource Type
- Journal article
- Publication Details
- Cell biochemistry and biophysics, Vol.28(2), pp.115-133
- Publisher
- Humana Press; Totowa
- DOI
- 10.1007/BF02737808
- PMID
- 9515163
- ISSN
- 1085-9195
- eISSN
- 1559-0283
- Language
- English
- Date published
- 06/1998
- Academic Unit
- Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Physics and Astronomy; Ophthalmology and Visual Sciences
- Record Identifier
- 9984025459602771
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