*  The Origin of Allosteric Binding of Transducin to Rhodopsin | IOVS | ARVO Journals
Abstract: : Purpose:Transducin activation by rhodopsin has been shown under positive allosteric control (Wessling-Resnick and Johnson, JBC 262,3996 (1987)). The origin of this allosteric behavior has not been identified. Chemical cross-linking study (Hingorani, et al., JBC,259,6694 (1984)) suggested that transducin forms supermolecular structure as large as [Tαßγ]4 in solution. In this study, the role of the tetrameric [Tαßγ]4 on the allosteric behavior of transducin is investigated. Methods:Correlations of the tetrameric transducin [Tαßγ]4 and its binding to rhodopsin have been studied by analytical ultracentrifugation and chemical modification methods. Specific inhibitory effect of bovine serum albumin (Buzdygon and Leibman, JBC,259,14567,(1984)) on the allosteric binding of transducin was examined. Results:Ultracentrifugation study confirmed that transducin in solution is under equilibrium of [Tαßγ]4 and ...
*  Mechanism of Light-Induced Translocation of Rod Transducin: GTP-Stimulated Release From the Membrane and Passive Diffusion |...
Purpose: : Transducin (Gt) is present in outer segments (OS) of dark-adapted rods, and it re-localizes to the inner compartments in light. Here we examined the molecular mechanism underlying this re-distribution. Methods: : Mouse eyecups or retinas were incubated, in light or dark, in a culture medium under conditions permitting the control of ATP, GTP or GTP analogs in the cells. Localization of rod and cone transducin subunits in the cells was examined by immunofluorescence microscopy. Retinas were fractionated by ultracentrifugation, and the presence of Gt was determined by western blot. The following mouse models were examined: 1. Gna1-/-; Gna2+, where cone Gαt is expressed in rods; 2. Nrl-/-, containing only cone-like photoreceptors; 3. Gß5-/-; and 4. RGS9-/-. N-Acylation status of Gαt was determined by mass-spectrometry. Results: : Re-localization of rod Gt in light occurs even in ATP-depleted rod cells. GTP is necessary and sufficient for the departure of Gt from the ...
*  Interactions between the subunits of transducin and cyclic GMP phosphodiesterase in Rana catesbiana rod photoreceptors. -...
In bullfrog (Rana catesbiana) rods the activity of cyclic GMP (cGMP) phosphodiesterase was stimulated 10 times by washing disc membranes with an isotonic, GTP-containing buffer. This stimulation was maintained following hydrolysis of GTP and after removal of guanine nucleotides. At least 60-70% of the inhibitory gamma subunit of cGMP phosphodiesterase (P gamma) was physically released from membranes by these washing procedures. When cGMP phosphodiesterase was activated by a hydrolysis-resistant GTP analogue, P gamma was found in the supernatant complexed with the transducin alpha subunit (T alpha) using three chromatography systems. When GTP was used to activate cGMP phosphodiesterase, P gamma was also found in the supernatant complexed with GDP.T alpha. This complex was also isolated using the same three chromatography systems, indicating that P gamma remained tightly bound to T alpha even after bound GTP was hydrolyzed. Interaction with the beta,gamma subunits of ...
*  Transducin alpha Research Products: Novus Biologicals
Transducin alpha products available through Novus Biologicals. Browse our Transducin alpha product catalog backed by our Guarantee+.
*  Calmodulin binding distinguishes between βγ subunits of activated G proteins and transducin | Biochemical Journal
The interactions between guanine nucleotide regulatory proteins and the Ca(2+)-binding protein calmodulin were studied using calmodulin-Sepharose affinity chromatography. Purified bovine brain beta gamma subunits bound to calmodulin-Sepharose in a Ca(2+)-dependent manner. On the contrary, beta gamma subunits produced in an activated Go/Gi preparation did not bind to calmodulin-Sepharose. The effect was independent of the type of bovine brain G protein (Go/Gi, Gs), method of activation and the presence of magnesium. To distinguish whether the binding of purified beta gamma subunits to calmodulin was unique to brain beta gamma or to the method of purification, similar experiments were performed using transducin. In contrast to bovine brain G proteins, both purified transducin beta gamma subunits and beta gamma released from rhodopsin-activated transducin bound to calmodulin-Sepharose in a Ca(2+)-dependent manner. To assess the functional significance of the ...
*  Proteolytic Fragmentation for Epitope Mapping | IRIS Università di Pisa
The use of antigen fragments generated by specific proteolytic cleavage is a relatively simple 'library' approach for epitope mapping in which possible overlapping fragments are screened with the antibody on Western blots. Proteolytic fragmentation with numerous proteases having different cleavage specificites can be carried out on native and denaturated proteins, generating a small and large number of fragments, respectively. To determine the antigenic site of a monoclonal antibody, we have examined the limited proteolytic digestion of the transducin alpha-subunit with four different proteases and detected antibody binding to fragments by Western blot. Using this approach, the epitope for this antibody was localized within the amino-terminal 17 residues of transducin alpha-subunit.. ...
*  B for Biology: Signal Transduction Pathway -The cGMP Pathway
A small molecule is associated with rhodopsin called 11-cis retinal. This small molecule absorbs light and isomerizes to all-trans retinal. As a result, it induces a conformational change in rhodposin protein. This activated rhodopsin then activates G protein called transducin. Being a G-protein, transducin has three subunits as α, β and γ. Just to recall, the α-subunit in inactive state is bound to GDP. Since, rhodopsin activates G protein transducin, there is a conformational change where α-subunit is now bound to GTP and is in active state. This α-subunit (of transducin) bound to GTP then stimulates the activity of cGMP phosphodiesterase. Now, being a phosphodiesterase, it reduces the intracellular levels of cGMP. The cGMP has a direct effect on ion channels in plasma membrane and so when there is reduction of cGMP levels in the rod cells of retina, this is translated to nerve impulse as light by the effect of cGMP on ion channels ...
*  Mylvaganam, Mol Vis 2006; 12:1496-1498.
Methods. The human GNB1 locus extends from base 1812355 (5' end) to 1706589 (3' end) in the genomic sequence of chromosome 1p (NCBI). The gene has 12 exons. There is an open reading frame in exons 3 to 11 with a coding sequence corresponding to the human cDNA sequence of the β-subunit of rod transducin (accession number BC004186) [6]. This human cDNA sequence encodes a polypeptide with a sequence identical to the β-subunit of rod transducin in both cattle (accession number BC105260) and mice (accession number NM_008142) [5-7]. We developed PCR-based methods to amplify individually each of the 12 exons of the human GNB1 gene. The primers used for PCR are in Table 1. Each set of primers amplified an entire exon as well as 10 to 72 bp of flanking intron DNA or untranslated region. We amplified the individual exonic fragments from genomic leukocyte DNA from 185 unrelated patients with ADRP. These patients came from families with at least two affected generations with RP; many ...
*  Rhodopsinn
Rhodopsin is the protein found in retinas that converts light into a molecular signal that is eventually transmitted to the brain as a nerve signal. It is located in the disks in the outer segments of rod cells. When a photon is absorbed by the protein's chromophore, retinal, it undergoes a cis-trans conformational change. This structural change is carried out in the context of the protein structure and generates a change in structure on the cytoplasmic side of the protein than causes it to interact with the G-protein, transducin. A series of intermolecular interactions involving the Transducin alpha subunit and a phosphodiesterase eventually causes a reduction in the levels of c-GMP and the associated closing of ion channels in the rod cells. This causes the cells to polarize and starts the nervous signal. We have recently solved the three-dimensional structure of rhodopsin (Science, 289, 739-745 (2000)). Much work remains to structurally characterize the various ...
*  Ying, Mol Vis 2000; 6:101-108. Figure 6.
Figure 6. Immunostaining of cone transducin. Immunostaining of cone transducin a-subunit (GNAT2) was done to identify cone photoreceptor cells in the central (Cr) and peripheral (Pr) retinas of a transgenic line 98 (Tg98) mouse and a wild-type littermate (WT) at the age of one month. The positive immunoreactive signals were stained brown. OS, outer segment; ONL, outer nuclear layer; INL, inner nuclear layer; G, ganglion cell layer. The bar at the lower right indicates 50 mm.. ...
*  "Photoreceptor phosphodiesterase: Interaction of inhibitory γ subunit a" by Nikolai O. Artemyev, Vadim Y. Arshavsky et al.
Abstract The photoreceptor phosphodiesterase (PDE6) is the central effector enzyme in the phototransduction cascade of photoreceptor cells. It is the only known PDE isoform the activity of which is regulated by interaction with a heterotrimeric G protein. The rod PDE6 holoenzyme is a tetrameric protein consisting of two large catalytic α and β subunits and two small γ subunits, which serve as potent inhibitors of PDE6. In dark-adapted photoreceptors, the γ subunits maintain PDE6 activity at a low level. When exposed to light the visual pigment rhodopsin activates the retinal G protein, transducin, leading to release of the inhibitory action of the γ subunits. In addition to the active sites where cGMP is hydrolyzed, the α and β catalytic subunits have high-affinity, noncatalytic cGMP binding sites. These noncatalytic sites do not directly regulate cGMP catalysis at the active site, but rather can modulate the affinity with which the γ subunits bind to the catalytic subunits. This ...
*  Structural Biochemistry/Protein Evolution - Wikibooks, open books for an open world
WD40 domain is one of the most abundant domains and is one of the most active domains of the eukaryotes. Their functions are deeply involved in cellular processes by playing a crucial role as hubs in cellular networks. WD40 Domain regulates diverse protein-protein interactions, especially those that scaffold. They are present in processes such as signal transduction, cell division, chemotaxis, RNA processing, and cytoskeleton construction. WD40 domains were first discovered in bovine beta-transducin, a subunit of the trimeric G protein transducin complex. It contains a series of sequence of approximately 44-60 residues with folds into seven-bladed beta-propellers. Each blade is designed in a four-stranded anti-parallel beta-sheet. WD40 is naturally exploited as seemingly more suitable than other domain candidates because it structurally more compelling. This means that WD40 domains form structures that are highly symmetrical in comparison to other domains that are involved ...
*  Plus it
The agonist radioligand (-)-N6-[125I]-p-hydroxyphenylisopropyl-adenosine ([ 125I]HPIA) was used to characterize adenosine recognition sites in porcine atrial membranes. [125I]HPIA showed saturable binding to an apparently homogeneous population of sites with a maximum binding capacity of 35 +/- 3 fmol/mg of protein and an equilibrium dissociation constant of 2.5 +/- 0.4 nM. Kinetic experiments were performed to address the molecular mechanism of [125I]HPIA binding in porcine atrial membranes. [125I]HPIA apparently interacts with the cardiac adenosine receptor in a simple bimolecular reaction. A kinetically derived [125I] HPIA dissociation constant (2.4 nM) was in good agreement with that parameter measured at equilibrium. Guanyl nucleotides negatively modulated [125I]HPIA binding by increasing its rate of dissociation. This finding is consonant with the formation of a ternary complex in porcine atrial membranes, consisting of ligand, receptor, and guanyl nucleotide-binding protein. Prototypic ...
*  Eye Opener: Physiology - Light stimulation of sensory cells
Figure 1: Cleavage of photopigments and transduction in rods and cones due to light stimulation. This causes a chemical bond change, resulting in a straightened molecule. Retinal detaches from opsin, causing conformational change in its shape. G-protein transducin binds to opsin and is activated. Hyperpolarization of the cell and reduced release of neurotransmitter ends the chain reaction. ...
*  GNAT2 Gene - GeneCards | GNAT2 Protein | GNAT2 Antibody
Complete information for GNAT2 gene (Protein Coding), G Protein Subunit Alpha Transducin 2, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
*  GNAT3 Gene - GeneCards | GNAT3 Protein | GNAT3 Antibody
Complete information for GNAT3 gene (Protein Coding), G Protein Subunit Alpha Transducin 3, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
*  OriGene - TBL1XR1 (NM 024665) cDNA Clone
TBL1XR1 - TBL1XR1 (untagged)-Human transducin (beta)-like 1 X-linked receptor 1 (TBL1XR1) available for purchase from OriGene - Your Gene Company.
*  OriGene - TBL1Y (NM 134259) cDNA Clone
TBL1Y - TBL1Y (untagged)-Human transducin (beta)-like 1, Y-linked (TBL1Y), transcript variant 3 available for purchase from OriGene - Your Gene Company.
β-transducin (G-β) is one of the three subunits (α, β, and γ) of the guanine nucleotide-binding proteins (G proteins) which act as intermediaries in the transduction of signals generated by transmembrane receptors [1]. The α subunit binds to and hydrolyzes GTP; the functions of the β and γ subunits are less clear but they seem to be required for the replacement of GDP by GTP as well as for membrane anchoring and receptor recognition. In higher eukaryotes G-β exists as a small multigene family of highly conserved proteins of about 340 amino acid residues. Structurally G-β consists of eight tandem repeats of about 40 residues, each containing a central Trp-Asp motif (this type of repeat is sometimes called a WD-40 repeat). Such a repetitive segment has been shown [2,3,4,5] to exist in a number of other proteins listed below: ...
*  Crystallizing proteins at low temperatures
Joe Noel crystallized transducin (G-protein) as -12C. I am not shure what was in the droplet. It was published about year ago. Contact Paul Sigler or Joe for more info. Zbyszek Otwinowski ...
*  TLE6 Gene - GeneCards | TLE6 Protein | TLE6 Antibody
Complete information for TLE6 gene (Protein Coding), Transducin Like Enhancer Of Split 6, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
*  texhax] BachoTeX 2015 approaching fast
Dear TeXies, a brief reminder: BachoTeX 2015: Various faces of typography ========================================== The early-bird registrations deadline for BachoTeX 2015 is approaching fast! You can register at http://www.gust.org.pl/bachotex/2015-en/registration/registration-form Please share with other TeXies -- we still do accept papers: * the call for papers is at http://www.gust.org.pl/bachotex/2015-en/cfp * info for authors is at http://www.gust.org.pl/bachotex/2015-en/submissions See you there! -- Jerzy Ludwichowski ...
*  Anabeta on a cut? - AnabolicMinds.com
I'm currently cutting and recently commenced PES Alpha T2 stacked with Oxyelite Pro. My question is whether adding Anabeta on a cut could achieve
*  Chertoff: Bio Terror 'Next Threat' For USA May be Just Months Away! - Stormfront
http://news.sky.com/skynews/Home/Wor..._Bio_Terrorism Quote: 'In an exclusive interview, homeland security secretary Michael Chertoff said source