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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By method of isoelectric focusing in polyacrylamide gel and sucrose density gradient it has been shown that rhodopsin preparation, obtained by different methods (including the rhodopsin with low content of lipids) are divided into a number of fractions with isoelectric points at the pH-range 5.4-6.0. The corresponding preparations of opsin show heterogeneity in pI, too. Heterogeneity in pI remains at denaturation conditions (8 M urea, 0.01% beta-mercaptoethanol, 1 mM EDTA). If separated in this system at least two protein components are detected. The nature of heterogeneity in pI found and its possible connection with complicated kinetics of the decay of early intermediate products of visual pigment are discussed.
Mol Biol (Mosk)
PMID:[Isoelectric focusing of rhodopsin]. 3 30

The kinetics of photoinduced changes of protein fluorescence of cattle visual pigment was studied in the presence of hydroxylamine. The rate constant of fluorescence increase is proportional to NH2OH concentration when it is less than 0.4 M. It reaches the maximal magnitude (3.3 +/- 1 sec-1) at higher hydroxylamine concentration. Fluorescence increase rate is controlled by the rate of chemical reaction of rhodopsin with hydroxylamine. It is limited by conformational rearrangement of opsin. This rearrangement does not induce absorbance spectrum change of visual pigment, but confers to it the capability to react with NH2OH and NaBH4. Kinetic parameters of this rearrangement (tau 20 degrees C approximately 300 msec, Eact = 19 +/- 2 kcal/mole) coincide with kinetic parameters of diminishing of the photoresponse of artificial lipid membrane modified by fragments of rod outer segments in the temperature range studied (+2 divided by +25 degrees C).
Mol Biol (Mosk)
PMID:[Molecular mechanisms of receptor-potential generation by the photoreceptor. III. Conformational transition responsible for the tail end of the photoresponse of an artificial lipid membrane modified by fragments of the external segments of rods]. 61 34

The protein fluorescence changes of rod outer segment fragments during bleaching were studied. Flash caused a fluorescence intensity drop by about 6%. The time constant of this process was approximately 30 msec and coincided with the time constant of increasing the permeability of an artificial lipid membrane containing rhodopsin and of Metarhodopsin I decay. In the presence of hydroxylamine the fluorescence intensity increases after the initial drop. The second process time constant was about 300 msec and coincided with the conduction drop time constant of the artificial membrane containing rhodopsin. A new intermediate -- Metarhodopsin II1 is proposed. It has the Metarhodopsin II absorption spectrum, lives for about 300 msec at room temperature, does not react with hydroxylamine, and increases the permeability of a disk membrane.
Mol Biol Rep 1976 Nov
PMID:The study of photoconduction of artificial lipid membranes incorporating rhodopsin. The simultaneous changes of membrane conduction and rhodopsin fluorescence. 101 78

The structure of the retinal rod disc membrane and its modifications upon bleaching have been studied by X-ray diffraction. Three types of preparations are used: functioning isolated from retina, isolated rods from frog retina, oriented by a magnetic field, and stacked discs from cattle retina. X-rays are detected by a position-sensitive linear counter. Diffraction spectra are obtained in 10-100 s. The electron density profile favors models where the rhodopsin molecule spans the whole thickness of the membrane. Upon bleaching, a small increase of electron density appears instantly at the cytoplasmic edge of the membrane. In the intact retina this structural change is accompanied by disorder and slow swelling reactions which are not observed in the isolated rod outer segment. The diffraction signal arising from the protein distribution in the plane of the membrane has been reinvestigated carefully. Patterns identical to those of Blasie (Blaise (1969) J. Mol. Biol. 39, 407 and Blaise (1972) Biophys. J. 12, 191) can be obtained but these are shown to be dominated by artefacts. The actual signal is a single broad band around (55 A)-1, upon which bleaching has a negligible effect. No measurable displacement of rhodopsin in the thickness of the membrane occurs upon bleaching. Temperature effects on the protein distribution are found to be large only for disc membranes from cattle retina. In this material from a warm-blooded animal those effects are correlated with the occurrence, upon lowering the temperature, of a partial phase transition of the paraffin chains of the lipids. The position and the slope of the transition are not sensitive to bleaching.
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PMID:X-ray diffraction studies of retinal rods. I. Structure of the disc membrane, effect of illumination. 107 41

Recently it has been demonstrated that some families with autosomal dominant retinitis pigmentosa (adRP) have mutations in the rhodopsin gene while others do not. Previously we have identified six such mutations in seven adRP families in this laboratory, one of which was previously described in US patients. We now present a completed screen of the rhodopsin gene in a panel of 39 adRP families, by a rapid screening technique which will be of use for routine diagnosis. Nine different mutations were ultimately found, in a total of twelve of the 39 families. These include the six previously identified mutations, in codons 68-71, 190, 211, 255, 296 and 347, two new ones in codons 53 and 106, and another mutation first identified in a single US patient, in codon 58. Thus approximately 30% of adRP families have 'Rhodopsin RP' while the remainder probably have a defect elsewhere in the genome. Of those families in which rhodopsin mutations have been found, four have been classified D type, three as sectorial RP and the remainder are of uncertain classification. All families excluded from chromosome 3q by linkage have been classified R type. These data suggest a correlation between clinical sub-classification and the underlying rhodopsin/non-rhodopsin heterogeneity.
Hum Mol Genet 1992 Apr
PMID:A completed screen for mutations of the rhodopsin gene in a panel of patients with autosomal dominant retinitis pigmentosa. 130 Nov 35

Retinitis Pigmentosa (RP) is a group of inherited retinopathies which affect approximately 1 in 4,000 individuals. The disorder can be classified on the basis of inheritance; dominant, recessive and X-linked forms have been well documented. The existence of genetic heterogeneity within autosomal dominant RP (adRP) had been previously demonstrated. As a result of extensive linkage studies in 2 large Irish families and 1 American pedigree three adRP genes have been mapped. adRP genes have been localised to chromosome 3q close to the rod photoreceptor gene, rhodopsin; to chromosome 6p close to another transmembrane photoreceptor gene, peripherin/RDS and to the pericentric region of chromosome 8, although the causative gene in this region has not yet been identified. Here we report the results of a linkage study in a Spanish family, who exhibit an early-onset form of adRP. The adRP gene segregating in this family has been excluded from the three known adRP loci on chromosomes 3q, 6p and 8 using a series of both intragenic microsatellite markers from the rhodopsin and peripherin/RDS genes and markers flanking the three known loci. These results provide definitive evidence for the existence of a fourth adRP locus, further emphasising the genetic heterogeneity that exists within adRP.
Hum Mol Genet 1992 Sep
PMID:Autosomal dominant retinitis pigmentosa (adRP): exclusion of a gene from three mapped loci provides evidence for the existence of a fourth locus. 130 15

Phoborhodopsin (also called sensory rhodopsin II) is a photoreceptor protein which mediates photophobic responses of Halobacterium halobium to blue-green light. Under conditions where the synthesis of the chromophore retinal is inhibited, the photophobic system is reconstituted in vivo by incorporation of all-trans retinal or retinal analogs into the apoprotein of phoborhodopsin. Retinal analogs which retard the cyclic photoreaction kinetics of phoborhodopsin increase significantly the sensitivity of the photophobic response. This supports the previously reported hypothesis that signal amplification occurs during the lifetime of intermediate states of the photocycle. The sensitivity increase caused by the chromophore substitution is observed in cells at several different growth stages, i.e. the naturally occurring chromophore (all-trans retinal) does not produce maximal sensitivity at any stage of the culture growth. These results are difficult to interpret in terms of the proposal by Marwan et al. (J. Mol. Biol. 199, 663-664, 1988) that only a single photon is sufficient to cause the photobehavioral response in cells containing native phoborhodopsin. A new interpretation for the fluence-response curves is described based in part on their Poisson statistical analysis. Further, a kinetic model which relates the receptor photochemical reaction cycle to the behavioral response is developed, which accounts for both the sensitivity increase and the shape of the fluence-response curves.
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PMID:Sensitivity increase in the photophobic response of Halobacterium halobium reconstituted with retinal analogs: a novel interpretation for the fluence-response relationship and a kinetic modeling. 149 28

A chromosomal origin of DNA replication has been localized within the single-copy rhodopsin gene locus in Chinese hamster (line CHO) cells using two methods. In the first method, single-copy segments were identified at 3 to 15 kb intervals within approximately 75 kb (kb = 10(3) bases) of cloned genomic DNA containing the early-replicating rhodopsin gene near its middle. The cloned single-copy segments were then used as hybridization probes to quantify the replication of their corresponding genomic segments as synchronized cells progressed into S phase. In the second method, genomic DNA synthesized in vivo or in permeabilized early S phase cells was hybridized with slot-blots of the cloned single-copy DNA segments to identify the earliest replicating part of the 75 kb mapped region. The first method indicates that the earliest replicating DNA is located within a 10 kb region beginning 4 kb upstream from and extending 1 kb beyond the rhodopsin gene. The second method confirms the location in the vicinity of the rhodopsin gene and indicates that the earliest replicating region is located within or very near the 4.5 kb rhodopsin gene itself. An extended region of 12 kb that encompasses the entire early-replicating region has been sequenced for analysis and comparison with currently characterized origin regions associated with the CHO dihydrofolate reductase (dhfr) and human c-myc genes. There are several sequence similarities between the dhfr rhodopsin origin regions, including common transcription promoter consensus sequences, rodent Alu repeats with their 3'-A+T rich flanking sequences, A+T-rich yeast ARS and Drosophila SAR consensus sequences, and simple (GA)n repeats, but there are no extended regions of direct similarity. The rhodopsin gene locus is the second sequenced CHO origin region.
J Mol Biol 1992 Mar 20
PMID:Localization and DNA sequence of a replication origin in the rhodopsin gene locus of Chinese hamster cells. 156 Apr 57

We have previously demonstrated that human bronchial smooth muscle cells possess a single class of high-affinity binding sites for endothelin 1. In this study, we further characterized the receptor for endothelin 1 and evaluated the signal transduction mechanisms of this peptide. Stimulation of cultured human bronchial smooth muscle cells with endothelin 1 induced mobilization of Ca2+ from both intracellular and extracellular pools with a biphasic increase in cytoplasmic free Ca2+ concentration. Endothelin 1 increased cellular levels of inositol phosphates and diacylglycerol, indicating activation of phospholipase C, but induced production of inositol phosphates in smooth muscle cell membranes only in the presence of guanosine 5'-O-(thiotriphosphate) (GTP gamma S). Treatment of smooth muscle cells with pertussis toxin failed to block the endothelin 1-induced increase in inositol phosphate production and Ca2+ mobilization. These results suggest that the receptor for endothelin 1 in bronchial smooth muscle is coupled to phospholipase C through a pertussis toxin-insensitive G protein. Affinity crosslinking experiments identified the endothelin 1 receptor as a single band with an apparent molecular weight of approximately 70,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis, further supporting the functional evidence that endothelin 1 receptor belongs to the G protein-linked rhodopsin type of receptor superfamily.
Am J Respir Cell Mol Biol 1991 Nov
PMID:Mechanisms of calcium mobilization and phosphoinositide hydrolysis in human bronchial smooth muscle cells by endothelin 1. 165 61

Rhodopsins share a limited number of amino acid identities with a variety of other integral membrane proteins. Most of these proteins have seven putative transmembrane segments and are likely to play a role in transmembrane signaling. We have undertaken a systematic series of comparisons of primary and secondary structure in order to clarify the functional and evolutionary significance of these sequence similarities. On the basis of consistently high similarity scores, we find that the most internally consistent definition of the rhodopsin gene family would include vertebrate rhodopsins, alpha- and beta-adrenergic receptors, M1 and M2 muscarinic acetylcholine receptors, substance K receptors, and insect rhodopsins, while excluding bacteriorhodopsin, the mass human oncogene, vertebrate and insect nicotinic acetylcholine receptors, and the yeast STE2 and STE3 peptide receptors. The rhodopsin gene family is highly diverged at the primary sequence level but has maintained a conserved secondary structure, including a previously unidentified hierarchy of transmembrane segment hydrophobicity. We have developed new computer algorithms for progressive multiple sequence alignment and the analysis of local conservation of protein domains, and we have used these algorithms to examine the phylogeny of the rhodopsin gene family and the changing domains of sequence conservation. The results show striking differences and similarities in the conserved domains in each of the three main branches of the rhodopsin gene family, and indicate that color vision arose independently in the lines of descent leading to modern humans and fruit flies.
J Mol Evol 1991 Oct
PMID:The evolution of rhodopsins and neurotransmitter receptors. 166 59


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