Femtosecond Spectroscopy of a 13-Demethylrhodopsin Visual Pigment Analogue:  The Role of Nonbonded Interactions in the Isomerization Process

1996 ◽  
Vol 100 (43) ◽  
pp. 17388-17394 ◽  
Author(s):  
Qing Wang ◽  
Gerd G. Kochendoerfer ◽  
Robert W. Schoenlein ◽  
Peter J. E. Verdegem ◽  
Johan Lugtenburg ◽  
...  
Keyword(s):  
Visual Pigment ◽  
Femtosecond Spectroscopy ◽  
Nonbonded Interactions ◽  
Isomerization Process

“In situ” observation of the role of chloride ion binding to monkey green sensitive visual pigment by ATR-FTIR spectroscopy

2018 ◽  
Vol 20 (5) ◽  
pp. 3381-3387 ◽  
Author(s):  
Kota Katayama ◽  
Yuji Furutani ◽  
Masayo Iwaki ◽  
Tetsuya Fukuda ◽  
Hiroo Imai ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Ftir Spectroscopy ◽  
Visual Pigment ◽  
Chloride Ion ◽  
Ion Binding ◽  
In Situ Observation ◽  
The Novel ◽  
Long Wavelength

ATR-FTIR spectroscopic study elucidates the novel role of Cl−-binding in primate long-wavelength-sensitive (LWS) visual pigment.

scholarly journals The role of retinal photoisomerase in the visual cycle of the honeybee.

1991 ◽  
Vol 97 (1) ◽  
pp. 143-165 ◽  
Author(s):  
W C Smith ◽  
T H Goldsmith
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Rod Outer Segments ◽  
Visual Cycle ◽  
In Vitro Techniques ◽  
The Third ◽  
Isomerization Processes

The compound eye of the honeybee has previously been shown to contain a soluble retinal photoisomerase which, in vitro, is able to catalyze stereospecifically the photoconversion of all-trans retinal to 11-cis retinal. In this study we combine in vivo and in vitro techniques to demonstrate how the retinal photoisomerase is involved in the visual cycle, creating 11-cis retinal for the generation of visual pigment. Honeybees have approximately 2.5 pmol/eye of retinal associated with visual pigments, but larger amounts (4-12 pmol/eye) of both retinal and retinol bound to soluble proteins. When bees are dark adapted for 24 h or longer, greater than 80% of the endogenous retinal, mostly in the all-trans configuration, is associated with the retinal photoisomerase. On exposure to blue light the retinal is isomerized to 11-cis, which makes it available to an alcohol dehydrogenase. Most of it is then reduced to 11-cis retinol. The retinol is not esterified and remains associated with a soluble protein, serving as a reservoir of 11-cis retinoid available for renewal of visual pigment. Alternatively, 11-cis retinal can be transferred directly to opsin to regenerate rhodopsin, as shown by synthesis of rhodopsin in bleached frog rod outer segments. This retinaldehyde cycle from the honeybee is the third to be described. It appears very similar to the system in another group of arthropods, flies, and differs from the isomerization processes in vertebrates and cephalopod mollusks.

Tosylate salts of the anticancer drug lapatinib

2013 ◽  
Vol 69 (12) ◽  
pp. 1516-1523 ◽  
Author(s):  
K. Ravikumar ◽  
B. Sridhar ◽  
Jagadeesh Babu Nanubolu ◽  
A. K. S. Bhujanga Rao ◽  
R. Jyothiprasad
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Physicochemical Properties ◽  
Anticancer Drug ◽  
Ring System ◽  
Nonbonded Interactions ◽  
One Dimensional ◽  
Drug Products ◽  
Ring Motif

Two tosylate salts of an anticancer drug lapatinib,viz. a monotosylate [systematic name: ({5-[4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)quinazolin-6-yl]furan-2-yl}methyl)[2-(methylsulfonyl)ethyl]azanium 4-methylbenzenesulfonate], C29H27ClFN4O4S+·C7H7O3S−, (I), and a ditosylate [systematic name: 4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)-6-]5-({[2-(methylsulfonyl)ethyl]azaniumyl}methyl)furan-2-yl[quinazolin-1-ium bis(4-methylbenzenesulfonate)], C29H28ClFN4O4S2+·2C7H7O3S−, (II), were obtained during crystallization attempts for polymorphism. In both structures, the lapatinib cation is in a distorted U-like conformation and the tosylate anion is clamped between the aniline N atom and methylamine N atom through N—H...O hydrogen bonds, forming anR22(15) ring motif. The 4-anilinoquinazoline ring system is essentially planar in (I), while it is twisted in (II), controlled by an intramolecular C—H...N interaction. In (I), alternating cations and anions are linked by N—H...O hydrogen bonds intoC22(6) chains. These chains are linked by cations in a helical manner. The presence of the additional tosylate anion in (II) results in the formation of one-dimensional tapes of fused hydrogen-bonded rings through N—H...O and C—H...O interactions. These studies augment our understanding of the role of nonbonded interactions in the solid state, which is useful for correlation to the physicochemical properties of drug products.

Vibrational Relaxation and Energy Migration of N-Methylacetamide in Water: The Role of Nonbonded Interactions

2015 ◽  
Vol 119 (7) ◽  
pp. 3112-3122 ◽  
Author(s):  
Pierre-André Cazade ◽  
Florent Hédin ◽  
Zhen-Hao Xu ◽  
Markus Meuwly
Keyword(s):  
Vibrational Relaxation ◽  
Energy Migration ◽  
Nonbonded Interactions

scholarly journals Turning Cones Off: the Role of the 9-Methyl Group of Retinal in Red Cones

2006 ◽  
Vol 128 (6) ◽  
pp. 671-685 ◽  
Author(s):  
Maureen E. Estevez ◽  
Petri Ala-Laurila ◽  
Rosalie K. Crouch ◽  
M. Carter Cornwall
Keyword(s):  
Visual Pigment ◽  
Bright Light ◽  
Rapid Rate ◽  
Methyl Group ◽  
Cone Opsin ◽  
Rate Of Recovery ◽  
Kinetics Of ◽  
Flash Response

Our ability to see in bright light depends critically on the rapid rate at which cone photoreceptors detect and adapt to changes in illumination. This is achieved, in part, by their rapid response termination. In this study, we investigate the hypothesis that this rapid termination of the response in red cones is dependent on interactions between the 9-methyl group of retinal and red cone opsin, which are required for timely metarhodopsin (Meta) II decay. We used single-cell electrical recordings of flash responses to assess the kinetics of response termination and to calculate guanylyl cyclase (GC) rates in salamander red cones containing native visual pigment as well as visual pigment regenerated with 11-cis 9-demethyl retinal, an analogue of retinal in which the 9-methyl group is missing. After exposure to bright light that photoactivated more than ∼0.2% of the pigment, red cones containing the analogue pigment had a slower recovery of both flash response amplitudes and GC rates (up to 10 times slower at high bleaches) than red cones containing 11-cis retinal. This finding is consistent with previously published biochemical data demonstrating that red cone opsin regenerated in vitro with 11-cis 9-demethyl retinal exhibited prolonged activation as a result of slowed Meta II decay. Our results suggest that two different mechanisms regulate the recovery of responsiveness in red cones after exposure to light. We propose a model in which the response recovery in red cones can be regulated (particularly at high light intensities) by the Meta II decay rate if that rate has been inhibited. In red cones, the interaction of the 9-methyl group of retinal with opsin promotes efficient Meta II decay and, thus, the rapid rate of recovery.

Role of Nonbonded Interactions in Determining Solution Conformations of Oligosaccharides

1994 ◽  
pp. 252-268 ◽  
Author(s):  
Robert J. Woods ◽  
Bert Fraser-Reid ◽  
Raymond A. Dwek ◽  
Christopher J. Edge
Keyword(s):  
Nonbonded Interactions ◽  
Solution Conformations

Role of Gln114 in Spectral Tuning of a Long-Wavelength Sensitive Visual Pigment

Biochemistry ◽  
2019 ◽  
Vol 58 (26) ◽  
pp. 2944-2952 ◽  
Author(s):  
Kota Katayama ◽  
Shunta Nakamura ◽  
Takuma Sasaki ◽  
Hiroo Imai ◽  
Hideki Kandori
Keyword(s):  
Visual Pigment ◽  
Spectral Tuning ◽  
Long Wavelength
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