1
|
Tamiya M, Isaka N, Kitazawa T, Hasegawa A, Ishizawa K, Ikeda M, Kawada S, Ishiguro M. Total Syntheses of the Non-Peptide Bradykinin B1 Receptor Antagonist Velutinol A and Its Analogs, seco-Pregnanes with a Cage-Like Moiety. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2019. [DOI: 10.1246/bcsj.20190048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Minoru Tamiya
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Nobuhisa Isaka
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Takaaki Kitazawa
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Atsushi Hasegawa
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Kazuya Ishizawa
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Mayu Ikeda
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Saki Kawada
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| | - Masaji Ishiguro
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 965-8603, Japan
| |
Collapse
|
2
|
Ohashi Y. Dynamic motion and various reaction paths of cobaloxime complexes in crystalline-state photoreaction. CRYSTALLOGR REV 2013. [DOI: 10.1080/0889311x.2012.752820] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
3
|
Hirano T, Lim IT, Kim DM, Zheng XG, Yoshihara K, Oyama Y, Imai H, Shichida Y, Ishiguro M. Constraints of Opsin Structure on the Ligand-binding Site: Studies with Ring-fused Retinals¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760606coosot2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
4
|
Liu RSH. Introduction to the Symposium-in-print: Photoisomerization Pathways, Torsional Relaxation and the Hula Twist¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760580ittsip2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
5
|
Bosch L, Cordomí A, Domínguez M, Toledo D, Morillo M, Pérez JJ, Alvarez R, de Lera AR, Garriga P. A methyl group at C7 of 11-cis-retinal allows chromophore formation but affects rhodopsin activation. Vision Res 2006; 46:4472-81. [PMID: 17027899 DOI: 10.1016/j.visres.2006.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 10/24/2022]
Abstract
The newly synthesized 11-cis-7-methylretinal can form an artificial visual pigment with kinetic and spectroscopic properties similar to the native pigment in the dark-state. However, its photobleaching behavior is altered, showing a Meta I-like photoproduct. This behavior reflects a steric constraint imposed by the 7-methyl group that affects the conformational change in the binding pocket as a result of retinal photoisomerization. Transducin activation is reduced, when compared to the native pigment with 11-cis-retinal. Molecular dynamics simulations suggest coupling of the C7 methyl group and the beta-ionone ring with Met207 in transmembrane helix 5 in agreement with recent experimental results.
Collapse
Affiliation(s)
- Laia Bosch
- Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, 08222 Terrassa, Catalonia, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Ishiguro M, Oyama Y, Hirano T. Structural Models of the Photointermediates in the Rhodopsin Photocascade, Lumirhodopsin, Metarhodopsin I, and Metarhodopsin II. Chembiochem 2004; 5:298-310. [PMID: 14997522 DOI: 10.1002/cbic.200300668] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Model building of the two photointermediates, lumirhodopsin and metarhodopsin I, and the activated form of rhodopsin, metarhodopsin II, is described. An outward swing of the C-terminal portion of transmembrane segment 3, pivoting on Cys110 at the N-terminal end of transmembrane segment 3, led to structural models of lumirhodopsin and metarhodopsin I. The conformation of the chromophore in the lumirhodopsin and metarhodopsin I models is controlled by the motion of transmembrane segment 3 and agreed closely with the hydrogen-bonding states of the protonated Schiff base in lumirhodopsin and metarhodopsin I as deduced from their FTIR and resonance Raman spectra and with the negative and positive CD bands of lumirhodopsin and metarhodopsin I, respectively. The structure of metarhodopsin II was constructed by an outward swing of transmembrane segment 3 and the rigid-body motion of transmembrane segment 6. The arrangement of the entire transmembrane segment of the metarhodopsin II model closely agreed with the electron paramagnetic resonance spectra of spin-labeled rhodopsin mutants and provided a structural basis for the protonation of Glu134, which is a key process in transducin activation.
Collapse
Affiliation(s)
- Masaji Ishiguro
- Suntory Institute for Bioorganic Research, 1 - 1 Wakayamadai, Shimamoto, Osaka 618-8503, Japan.
| | | | | |
Collapse
|
7
|
Liu RSH, Colmenares LU. The molecular basis for the high photosensitivity of rhodopsin. Proc Natl Acad Sci U S A 2003; 100:14639-44. [PMID: 14657350 PMCID: PMC299751 DOI: 10.1073/pnas.2536769100] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2003] [Indexed: 11/18/2022] Open
Abstract
Based on structural information derived from the F NMR data of labeled rhodopsins, rhodopsin crystal structure, and excited-state properties of model polyenes, we propose a molecular mechanism that accounts specifically for the causes of the well-known enhanced photoreactivity of rhodopsin (increased rates and quantum yield of isomerization). It involves the key features of close proximity of C-187 to H-12 and chromophore bond lengthening upon light absorption. The resultant "sudden punch" to H-12 triggers dual processes of decay of the Franck-Condon-excited rhodopsin, a productive directed photoisomerization and a nonproductive decay returning to the ground state as two separate molecular pathways [based on real-time fluorescence results of Chosrowjan, H., Mataga, N., Shibata, Y., Tachibanaki, S., Kandori, H., Shichida, Y., Okada, T. & Kouyama, T. (1998) J. Am. Chem. Soc. 120, 9706-9707]. The two processes are controlled by the local protein structure: an empty space provided by the intradiscal loop connecting transmembrane helices 4 and 5 and a protein wall composed of amino acid units in transmembrane 3. Suggestions, involving retinal analogs and rhodopsin mutants, to improve the unusually high photosensitivity of rhodopsin are proposed.
Collapse
Affiliation(s)
- Robert S H Liu
- Department of Chemistry, University of Hawaii, Honolulu, HI 96822, USA.
| | | |
Collapse
|
8
|
Ishiguro M, Hirano T, Oyama Y. Modelling of photointermediates suggests a mechanism of the flip of the beta-ionone moiety of the retinylidene chromophore in the rhodopsin photocascade. Chembiochem 2003; 4:228-31. [PMID: 12616639 DOI: 10.1002/cbic.200390037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Masaji Ishiguro
- Suntory Institute for Bioorganic Research, Shimamoto, Osaka 618-8503, Japan.
| | | | | |
Collapse
|
9
|
Ohhara T, Ikeda S, Imura H, Uekusa H, Ohashi Y, Tanaka I, Niimura N. Direct observation of deuterium migration in crystalline-state reaction by single crystal neutron diffraction IV. "Hula-twist" rotation of a long alkyl radical produced by photoirradiation. J Am Chem Soc 2002; 124:14736-40. [PMID: 12465986 DOI: 10.1021/ja027872g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
When the crystal of [(R)-1,2-bis(ethoxycarbonyl)ethyl](pyridine)bis(dimethylglyoximato)cobalt(III) was exposed to a xenon lamp, the chiral 1,2-bis(ethoxycarbonyl)ethyl group was partly inverted to the opposite configuration and finally the racemic group was produced with retention of the single crystal form. To make clear the mechanism, the hydrogen atom bonded to the chiral carbon of the chiral group was exchanged with the deuterium atom and the crystal was exposed to the xenon lamp for 3 days. The crystal after irradiation was analyzed by neutron diffraction. About 33% of the (R)-isomers were inverted to the (S) isomers in a crystal. The deuterium atom in the (S)-isomer was bonded to the same chiral carbon atom. This result clearly indicates that the inversion proceeds in the three steps; (i) the Co-C bond was homolytically cleaved by photoirradiation and the 1,2-bis(ethoxycarbonyl)ethyl radical and Co(II) were produced, (ii) the radical rotated by 180 degrees directing the C-D bond to the cobalt atom and the opposite plane of the radical faced to the cobalt atom, and (iii) the radical made a bond with Co(II). Because the peripheral atoms of the long radical occupy approximately the same positions in the process of the radical rotation, the crystal was not decomposed. The above rotation is a good example of hula-twist rotation in the process of photoisomerization of polyenes such as rhodopsin.
Collapse
Affiliation(s)
- Takashi Ohhara
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801, Japan
| | | | | | | | | | | | | |
Collapse
|
10
|
Liu RSH. Introduction to the symposium-in-print: photoisomerization pathways, torsional relaxation and the hula twists. Photochem Photobiol 2002; 76:580-3. [PMID: 12511036 DOI: 10.1562/0031-8655(2002)076<0580:ittsip>2.0.co;2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A review of recent literature on volume-conserving cis-trans photoisomerization reaction mechanism, including hula twist, is presented. Differences between substrates trapped in amorphous solids and chromophores that are protein bound are discussed.
Collapse
Affiliation(s)
- Robert S H Liu
- Department of Chemistry, University of Hawaii, Honolulu, HI 96822, USA.
| |
Collapse
|
11
|
Hirano T, Lim IT, Kim DM, Zheng XG, Yoshihara K, Oyama Y, Imai H, Shichida Y, Ishiguro M. Constraints of opsin structure on the ligand-binding site: studies with ring-fused retinals. Photochem Photobiol 2002; 76:606-15. [PMID: 12511040 DOI: 10.1562/0031-8655(2002)076<0606:coosot>2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ring-fused retinal analogs were designed to examine the hula-twist mode of the photoisomerization of the 9-cis retinylidene chromophore. Two 9-cis retinal analogs, the C11-C13 five-membered ring-fused and the C12-C14 five-membered ring-fused retinal derivatives, formed the pigments with opsin. The C11-C13 ring-fused analog was isomerized to a relaxed all-trans chromophore (lambda(max) > 400 nm) at even -269 degrees C and the Schiff base was kept protonated at 0 degrees C. The C12-C14 ring-fused analog was converted photochemically to a bathorhodopsin-like chromophore (lambda(max) = 583 nm) at -196 degrees C, which was further converted to the deprotonated Schiff base at 0 degrees C. The model-building study suggested that the analogs do not form pigments in the retinal-binding site of rhodopsin but form pigments with opsin structures, which have larger binding space generated by the movement of transmembrane helices. The molecular dynamics simulation of the isomerization of the analog chromophores provided a twisted C11-C12 double bond for the C12-C14 ring-fused analog and all relaxed double bonds with a highly twisted C10-C11 bond for the C11-C13 ring-fused analog. The structural model of the C11-C13 ring-fused analog chromophore showed a characteristic flip of the cyclohexenyl moiety toward transmembrane segments 3 and 4. The structural models suggested that hula twist is a primary process for the photoisomerization of the analog chromophores.
Collapse
Affiliation(s)
- Takahiro Hirano
- Suntory Institute for Bioorganic Research, Shimamoto, Osaka, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Fujimoto Y, Fishkin N, Pescitelli G, Decatur J, Berova N, Nakanishi K. Solution and biologically relevant conformations of enantiomeric 11-cis-locked cyclopropyl retinals. J Am Chem Soc 2002; 124:7294-302. [PMID: 12071738 DOI: 10.1021/ja020083e] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To gain information on the conformation of the 11-cis-retinylidene chromophore bound to bovine opsin, the enantiomeric pair (2a and 2b) of 11-cis-locked bicyclo[5.1.0]octyl retinal (retCPr) 2 was prepared and its conformation was investigated by NMR, geometry optimization, and CD calculations. This compound is also of interest since it contains a unique moiety in which a chiral cyclopropyl group is flanked by triene and enal chromophores, and hence would clarify the little-known chiroptical contribution of a cyclopropyl ring linked to polyene systems. NMR revealed that the seven-membered ring of retCPr adopts a twist chair conformation. The NMR-derived structure constraints were then used for optimizing the geometry of 2 with molecular mechanics and ab initio methods. This revealed that enantiomer 2a with a 11 beta,12 beta-cyclopropyl group exists as two populations of diastereomers depending on the twist around the 6-s bond; however, the sense of twist around the 12-s is positive in both rotamers. The theoretical Boltzmann-weighted CD obtained with the pi-SCF-CI-DV MO method and experimental spectra were consistent, thus suggesting that the conjugative effect of the cyclopropyl moiety is minimal. It was found that only the beta-cyclopropyl enantiomer 2a, but not the alpha-enantiomer 2b, binds to opsin. This observation, together with earlier retinal analogues incorporation results, led to the conclusion that the chromophore sinks into the N-terminal of the opsin receptor from the side of the 4-methylene and 15-aldehyde, and that the binding cleft accommodates 11-cis-retinal with a slightly positive twist around C12/C13. A reinterpretation of the previously published negative CD couplet of 11,12-dihydrorhodopsin also leads to a chromophoric C12/C13 twist conformation with the 13-Me in front as in 1b. Such a conformation for the chromophore accounts for both the observed biostereoselectivity of retCPr 2a and the observed negative couplet of 11,12-dihydro-Rh7.
Collapse
Affiliation(s)
- Yukari Fujimoto
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | | | | | | | | | | |
Collapse
|
13
|
Indra B, Matsunaga K, Hoshino O, Suzuki M, Ogasawara H, Ishiguro M, Ohizumi Y. Structure-activity relationship on (+/-)-nantenine derivatives in antiserotonergic activities in rat aorta. Can J Physiol Pharmacol 2002; 80:198-204. [PMID: 11991230 DOI: 10.1139/y02-019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of nine (+/-)-nantenine derivatives were synthesized and assayed for their pharmacological activities by using tension in aorta and binding experiments in rat brain membrane. Replacing a methyl group with a hydrogen ((+/-)-nornantenine) and an ethyl group at a nitrogen atom ((+/-)-ethylnornantenine) or introducing a hydroxyl group at the alpha/beta position of C-4 or displacement of a methoxy moiety at the C-1 position with a hydroxyl ((+/-)-domesticine) of (+/-)-nantenine decreased the affinity. Moreover, changing a methyl group of (+/-)-domesticine to hydrogen at a nitrogen atom ((+/-)-nordomesticine) caused loss of the activities. These results suggest that a methyl group at a nitrogen atom and a methoxy moiety at C-1 play important roles in the development of the antiserotonergic activity. Molecular modeling analysis of the interaction between the 5-HT2A receptor and (+/-)-nantenine suggested that electron lone pairs of N-6 and of the oxygen atom of the methoxy group at C-1 are important in forming a hydrogen bond to Asp155 and Asn343 of the 5-HT2A receptor, respectively.
Collapse
MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Aporphines/chemical synthesis
- Aporphines/chemistry
- Aporphines/pharmacology
- Frontal Lobe/metabolism
- In Vitro Techniques
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Radioligand Assay
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A
- Receptors, Serotonin/metabolism
- Serotonin Antagonists/chemical synthesis
- Serotonin Antagonists/pharmacology
- Stereoisomerism
- Structure-Activity Relationship
Collapse
Affiliation(s)
- Bachtiar Indra
- Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Sendai, Japan
| | | | | | | | | | | | | |
Collapse
|
14
|
Abstract
ALiu and Hammond recently reasoned that the hula-twist (HT), a volume-conserving cis-trans isomerization mechanism, is involved in reactions of confined systems. We now show that HT can be applied to various reported photochemical isomerization of chromophores (small organic systems as well as photoactive bio-pigments). The results, when taken as a whole, argue powerfully that HT is a common supramolecular photoisomerization reaction mechanism.
Collapse
Affiliation(s)
- R S Liu
- Department of Chemistry, University of Hawaii, Honolulu 96822, USA.
| | | |
Collapse
|
15
|
Fujimoto Y, Ishihara J, Maki S, Fujioka N, Wang T, Furuta T, Fishkin N, Borhan B, Berova N, Nakanishi K. On the bioactive conformation of the rhodopsin chromophore: absolute sense of twist around the 6-s-cis bond. Chemistry 2001; 7:4198-204. [PMID: 11686599 DOI: 10.1002/1521-3765(20011001)7:19<4198::aid-chem4198>3.0.co;2-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Incubation of opsin with synthetic 6-s-locked retinoids 2a and 2b only led to pigment formation from the alpha-locked 2a, the CD spectrum of which was similar to that of native rhodopsin (Rh). This establishes that the 6-s-bond of the chromophore in rhodopsin is cis, and that its helicity is negative. Earlier cross-linking studies showed that the 11-cis to all-trans photoisomerization occurring in the batho-Rh to lumi-Rh conversion induces a flip over of the side carrying the ring moiety. The GTP-binding assay of pigment Rh-(2a), incorporating retinal analogue 2a, has shown that its activity is 80% that of the native pigment. That is, the overall conformation around the 6-s bond is retained in the steps leading to G-protein activation.
Collapse
Affiliation(s)
- Y Fujimoto
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Liu RS. Photoisomerization by hula-twist: a fundamental supramolecular photochemical reaction. Acc Chem Res 2001; 34:555-62. [PMID: 11456473 DOI: 10.1021/ar000165c] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The volume-conserving hula-twist cis/trans isomerization process has been incorporated in a general scheme for photoisomerization of polyenes, applicable to small organic molecules as well as to protein-bound polyene chromophores. The main theme is that in solution the conventional one-bond-flip mechanism dominates, while in frozen media (or under other forms of supramolecular constraint) the hula-twist mechanism takes over. Literature examples of photoisomerization obtained under confined conditions have been critically reviewed, the applicability of HT has been examined, and new systems unambiguously testing this volume-conserving process are proposed.
Collapse
Affiliation(s)
- R S Liu
- Department of Chemistry, University of Hawaii, 2545 The Mall, Honolulu, Hawaii 96822, USA.
| |
Collapse
|
17
|
Hatanaka Y, Ishiguro M, Hashimoto M, Gastinel LN, Nakagomi K. A model of photoprobe docking with beta1,4-galactosyltransferase identifies a possible carboxylate involved in glycosylation steps. Bioorg Med Chem Lett 2001; 11:411-3. [PMID: 11212123 DOI: 10.1016/s0960-894x(00)00676-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A molecular docking study has been performed on the interaction of beta1,4-galactosyltransferase with an acceptor site photoprobe. This is based on an acceptor site peptide fragment which was recently identified by the use of a photoprobe. The present model strongly suggests that the carboxylate group of Asp318 could be involved in the activation of the acceptor sugar 4-OH for the efficient galactosyltransfer. The result also exemplified that the combination of photoaffinity labeling with crystallography is a powerful method for the detailed structural analysis of ligand protein complex.
Collapse
Affiliation(s)
- Y Hatanaka
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
| | | | | | | | | |
Collapse
|
18
|
Metzler DE, Metzler CM, Sauke DJ. Light and Life. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50026-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
19
|
Liu RS, Hammond GS. The case of medium-dependent dual mechanisms for photoisomerization: one-bond-flip and hula-twist. Proc Natl Acad Sci U S A 2000; 97:11153-8. [PMID: 11016972 PMCID: PMC17169 DOI: 10.1073/pnas.210323197] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper critically reviews examples in the literature of photochemical cis-trans isomerization paying particular attention to the medium effect and accompanied conformational changes. A case is made that the Hula-Twist mechanism, postulated in 1985 as a photochemical reaction pathway for a polyene chromophore imbedded in a protein binding cavity such as those of rhodopsin and bacteriorhodopsin, is also a dominant reaction pathway for a diene, or a longer polyene confined in a rigid (relative to isomerization rate) medium. The conventional one-bond-flip process is the preferred reaction pathway in a fluid medium. While defining experiments are proposed, this dual mechanistic approach successfully accounts for all examples in the literature on photoisomerization reactions whether involving conformational changes or not.
Collapse
Affiliation(s)
- R S Liu
- Department of Chemistry, University of Hawaii, 2545 The Mall, Honolulu, HI 96822, USA.
| | | |
Collapse
|