51
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Katayama K, Furutani Y, Imai H, Kandori H. An FTIR study of monkey green- and red-sensitive visual pigments. Angew Chem Int Ed Engl 2010; 49:891-4. [PMID: 20052695 DOI: 10.1002/anie.200903837] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Kota Katayama
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
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52
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Valsson O, Filippi C. Photoisomerization of Model Retinal Chromophores: Insight from Quantum Monte Carlo and Multiconfigurational Perturbation Theory. J Chem Theory Comput 2010. [DOI: 10.1021/ct900692y] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Omar Valsson
- Faculty of Science and Technology and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Claudia Filippi
- Faculty of Science and Technology and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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53
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Yamada K, Kawanabe A, Kandori H. Importance of Alanine at Position 178 in Proteorhodopsin for Absorption of Prevalent Ambient Light in the Marine Environment. Biochemistry 2010; 49:2416-23. [DOI: 10.1021/bi9020204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Keisuke Yamada
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Akira Kawanabe
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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54
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Altun A, Yokoyama S, Morokuma K. Color tuning in short wavelength-sensitive human and mouse visual pigments: ab initio quantum mechanics/molecular mechanics studies. J Phys Chem A 2010; 113:11685-92. [PMID: 19630373 DOI: 10.1021/jp902754p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the protonation state and photoabsorption spectrum of Schiff-base (SB) nitrogen bound 11-cis-retinal in human blue and mouse UV cone visual pigments as well as in bovine rhodopsin by hybrid quantum mechanical/molecular mechanical (QM/MM) calculations. We have employed both multireference (MRCISD+Q, MR-SORCI+Q, and MR-DDCI2+Q) and single reference (TD-B3LYP and RI-CC2) QM methods. The calculated ground-state and vertical excitation energies show that UV-sensitive pigments have deprotonated SB nitrogen, while violet-sensitive pigments have protonated SB nitrogen, in agreement with some indirect experimental evidence. A significant blue shift of the absorption maxima of violet-sensitive pigments relative to rhodopsins arises from the increase in bond length alternation of the polyene chain of 11-cis-retinal induced by polarizing fields of these pigments. The main counterion is Glu113 in both violet-sensitive vertebrate pigments and bovine rhodopsin. Neither Glu113 nor the remaining pigment has a significant influence on the first excitation energy of 11-cis-retinal in the UV-sensitive pigments that have deprotonated SB nitrogen. There is no charge transfer between the SB and beta-ionone terminals of 11-cis-retinal in the ground and first excited states.
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Affiliation(s)
- Ahmet Altun
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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55
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Katayama K, Furutani Y, Imai H, Kandori H. An FTIR Study of Monkey Green- and Red-Sensitive Visual Pigments. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200903837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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56
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Fujimoto KJ, Asai K, Hasegawa JY. Theoretical study of the opsin shift of deprotonated retinal schiff base in the M state of bacteriorhodopsin. Phys Chem Chem Phys 2010; 12:13107-16. [DOI: 10.1039/c0cp00361a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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57
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Neugebauer J. Subsystem-Based Theoretical Spectroscopy of Biomolecules and Biomolecular Assemblies. Chemphyschem 2009; 10:3148-73. [DOI: 10.1002/cphc.200900538] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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Fujimoto K, Hasegawa JY, Nakatsuji H. Color Tuning Mechanism of Human Red, Green, and Blue Cone Pigments: SAC-CI Theoretical Study. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.1140] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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59
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Tomasello G, Olaso-González G, Altoè P, Stenta M, Serrano-Andrés L, Merchán M, Orlandi G, Bottoni A, Garavelli M. Electrostatic control of the photoisomerization efficiency and optical properties in visual pigments: on the role of counterion quenching. J Am Chem Soc 2009; 131:5172-86. [PMID: 19309158 DOI: 10.1021/ja808424b] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hybrid QM(CASPT2//CASSCF/6-31G*)/MM(Amber) computations have been used to map the photoisomerization path of the retinal chromophore in Rhodopsin and explore the reasons behind the photoactivity efficiency and spectral control in the visual pigments. It is shown that while the electrostatic environment plays a central role in properly tuning the optical properties of the chromophore, it is also critical in biasing the ultrafast photochemical event: it controls the slope of the photoisomerization channel as well as the accessibility of the S(1)/S(0) crossing space triggering the ultrafast decay. The roles of the E113 counterion, the E181 residue, and the other amino acids of the protein pocket are explicitly analyzed: it appears that counterion quenching by the protein environment plays a key role in setting up the chromophore's optical properties and its photochemical efficiency. A unified scenario is presented that discloses the relationship between spectroscopic and mechanistic properties in rhodopsins and allows us to draw a solid mechanism for spectral tuning in color vision pigments: a tunable counterion shielding appears as the elective mechanism for L<-->M spectral modulation, while a retinal conformational control must dictate S absorption. Finally, it is suggested that this model may contribute to shed new light into mutations-related vision deficiencies that opens innovative perspectives for experimental biomolecular investigations in this field.
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Affiliation(s)
- Gaia Tomasello
- Dipartimento di Chimica G. Ciamician, Università di Bologna, via Selmi 2, Bologna I-40126, Italy
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60
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Yoshitsugu M, Yamada J, Kandori H. Color-changing mutation in the E-F loop of proteorhodopsin. Biochemistry 2009; 48:4324-30. [PMID: 19334675 DOI: 10.1021/bi900228a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is usually assumed that only amino acids located near the retinal chromophore are responsible for color tuning of rhodopsins. However, we recently found that replacement of Ala178 with Arg in the E-F loop of proteorhodopsin (PR), an archaeal-type rhodopsin in marine bacteria, shifts the lambda(max) from 525 to 545 nm at neutral pH [Yoshitsugu, M., Shibata, M., Ikeda, D., Furutani, Y., and Kandori, H. (2008) Angew. Chem., Int. Ed. 47, 3923-3926]. Since the location of Ala178 is distant from the retinal chromophore (approximately 25 A), the molecular mechanism of the unusual mutation effect on color tuning is intriguing. Here we studied this mechanism by using additional mutations and some analytical methods. Introduction of Arg into the corresponding amino acid in bacteriorhodopsin (BR, M163R mutant) does not change the absorption spectra, indicating that the effect is specific to PR. Introduction of Arg into the A-B or C-D loop yields little (3 nm) or no color change, respectively. T177R and P180R mutants exhibited absorption spectra identical to that of the wild type, while N176R and S179R mutants exhibit lambda(max) values of 528 and 535 nm, respectively. Therefore, the observed color change is position-specific, being fully effective at position 178 and half-effective at position 179. Salt affects the absorption spectra of wild-type and A178R PR similarly. FTIR spectroscopy at 77 K indicated similar chromophore structures for wild-type and A178R PR, and A178R PR pumps protons normally. We infer that the E-F loop has a unique structure in PR and the mutation of Ala178 disrupts the structure that includes the transmembrane region, leading to the observed changes in color and pK(a).
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Affiliation(s)
- Maiko Yoshitsugu
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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61
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62
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Keal TW, Wanko M, Thiel W. Assessment of semiempirical methods for the photoisomerisation of a protonated Schiff base. Theor Chem Acc 2009. [DOI: 10.1007/s00214-009-0546-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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63
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Abstract
The role of water molecules in spectral tuning of proteins has been left largely unexplored. This topic is important because changing hydrogen bond patterns during the activation process may lead to spectral shifts which can be of diagnostic value for the underlying structures. Arguments put forward in this article are based on spectral shift calculations of the rhodopsin and bathorhodopsin chromophore due to wat2a and 2b in the presence and absence of the counterion and of the amino acids lining the rhodopsin binding pocket. They show, among others, that a single water molecule can shift the absorbance by up to 0.1 eV or 34 nm depending on the environment of the chromophore.
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64
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Nielsen MB. Model systems for understanding absorption tuning by opsin proteins. Chem Soc Rev 2009; 38:913-24. [DOI: 10.1039/b802068j] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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65
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Altun A, Yokoyama S, Morokuma K. Mechanism of Spectral Tuning Going from Retinal in Vacuo to Bovine Rhodopsin and its Mutants: Multireference ab Initio Quantum Mechanics/Molecular Mechanics Studies. J Phys Chem B 2008; 112:16883-90. [DOI: 10.1021/jp807172h] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ahmet Altun
- Cherry L. Emerson Center for Scientific Computation, Department of Chemistry, and Department of Biology, Rollins Research Center, Emory University, Atlanta, Georgia 30322, USA and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Shozo Yokoyama
- Cherry L. Emerson Center for Scientific Computation, Department of Chemistry, and Department of Biology, Rollins Research Center, Emory University, Atlanta, Georgia 30322, USA and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Keiji Morokuma
- Cherry L. Emerson Center for Scientific Computation, Department of Chemistry, and Department of Biology, Rollins Research Center, Emory University, Atlanta, Georgia 30322, USA and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
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66
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Three-Layer ONIOM Studies of the Dark State of Rhodopsin: The Protonation State of Glu181. J Mol Biol 2008; 383:106-21. [DOI: 10.1016/j.jmb.2008.08.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 07/29/2008] [Accepted: 08/01/2008] [Indexed: 11/18/2022]
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67
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Szymczak JJ, Barbatti M, Lischka H. Mechanism of Ultrafast Photodecay in Restricted Motions in Protonated Schiff Bases: The Pentadieniminium Cation. J Chem Theory Comput 2008; 4:1189-99. [DOI: 10.1021/ct800148n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jaroslaw J. Szymczak
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria
| | - Mario Barbatti
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria
| | - Hans Lischka
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria
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68
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Yoshitsugu M, Shibata M, Ikeda D, Furutani Y, Kandori H. Color change of proteorhodopsin by a single amino acid replacement at a distant cytoplasmic loop. Angew Chem Int Ed Engl 2008; 47:3923-6. [PMID: 18404767 DOI: 10.1002/anie.200705989] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Maiko Yoshitsugu
- Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
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69
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Altun A, Yokoyama S, Morokuma K. Spectral tuning in visual pigments: an ONIOM(QM:MM) study on bovine rhodopsin and its mutants. J Phys Chem B 2008; 112:6814-27. [PMID: 18473437 DOI: 10.1021/jp709730b] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated geometries and excitation energies of bovine rhodopsin and some of its mutants by hybrid quantum mechanical/molecular mechanical (QM/MM) calculations in ONIOM scheme, employing B3LYP and BLYP density functionals as well as DFTB method for the QM part and AMBER force field for the MM part. QM/MM geometries of the protonated Schiff-base 11- cis-retinal with B3LYP and DFTB are very similar to each other. TD-B3LYP/MM excitation energy calculations reproduce the experimental absorption maximum of 500 nm in the presence of native rhodopsin environment and predict spectral shifts due to mutations within 10 nm, whereas TD-BLYP/MM excitation energies have red-shift error of at least 50 nm. In the wild-type rhodopsin, Glu113 shifts the first excitation energy to blue and accounts for most of the shift found. Other amino acids individually contribute to the first excitation energy but their net effect is small. The electronic polarization effect is essential for reproducing experimental bond length alternation along the polyene chain in protonated Schiff-base retinal, which correlates with the computed first excitation energy. It also corrects the excitation energies and spectral shifts in mutants, more effectively for deprotonated Schiff-base retinal than for the protonated form. The protonation state and conformation of mutated residues affect electronic spectrum significantly. The present QM/MM calculations estimate not only the experimental excitation energies but also the source of spectral shifts in mutants.
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Affiliation(s)
- Ahmet Altun
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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70
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Yoshitsugu M, Shibata M, Ikeda D, Furutani Y, Kandori H. Color Change of Proteorhodopsin by a Single Amino Acid Replacement at a Distant Cytoplasmic Loop. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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71
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Effect of opsin on the shape of the potential energy surfaces at the conical intersection of the Rhodopsin chromophore. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.03.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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72
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Altun A, Yokoyama S, Morokuma K. Quantum mechanical/molecular mechanical studies on spectral tuning mechanisms of visual pigments and other photoactive proteins. Photochem Photobiol 2008; 84:845-54. [PMID: 18331400 DOI: 10.1111/j.1751-1097.2008.00308.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The protein environments surrounding the retinal tune electronic absorption maximum from 350 to 630 nm. Hybrid quantum mechanical/molecular mechanical (QM/MM) methods can be used in calculating excitation energies of retinal in its native protein environments and in studying the molecular basis of spectral tuning. We hereby review recent QM/MM results on the phototransduction of bovine rhodopsin, bacteriorhodopsin, sensory rhodopsin II, nonretinal photoactive yellow protein and their mutants.
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Affiliation(s)
- Ahmet Altun
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, GA, USA
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73
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Thut M, Manca C, Tanner C, Leutwyler S. Spectral tuning by switching C–H⋯O hydrogen bonds: Rotation-induced spectral shifts of 7-hydroxyquinoline∙HCOOH isomers. J Chem Phys 2008; 128:024304. [DOI: 10.1063/1.2816710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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74
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Montero-Cabrera LA, Röhrig U, Padrón-Garcia JA, Crespo-Otero R, Montero-Alejo AL, Garcia de la Vega JM, Chergui M, Rothlisberger U. CNDOL: A fast and reliable method for the calculation of electronic properties of very large systems. Applications to retinal binding pocket in rhodopsin and gas phase porphine. J Chem Phys 2007; 127:145102. [DOI: 10.1063/1.2761869] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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75
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Bravaya K, Bochenkova A, Granovsky A, Nemukhin A. An opsin shift in rhodopsin: retinal S0-S1 excitation in protein, in solution, and in the gas phase. J Am Chem Soc 2007; 129:13035-42. [PMID: 17924622 DOI: 10.1021/ja0732126] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We considered a series of model systems for treating the photoabsorption of the 11-cis retinal chromophore in the protonated Schiff-base form in vacuum, solutions, and the protein environment. A high computational level, including the quantum mechanical-molecular mechanical (QM/MM) approach for solution and protein was utilized in simulations. The S0-S1 excitation energies in quantum subsystems were evaluated by means of an augmented version of the multiconfigurational quasidegenerate perturbation theory (aug-MCQDPT2) with the ground-state geometry parameters optimized in the density functional theory PBE0/cc-pVDZ approximation. The computed positions of absorption bands lambdamax, 599(g), 448(s), and 515(p) nm for the gas phase, solution, and protein, respectively, are in excellent agreement with the corresponding experimental data, 610(g), 445(s), and 500(p) nm. Such consistency provides a support for the formulated qualitative conclusions on the role of the chromophore geometry, environmental electrostatic field, and the counterion in different media. An essentially nonplanar geometry conformation of the chromophore group in the region of the C14-C15 bond was obtained for the protein, in particular, owing to the presence of the neighboring charged amino acid residue Glu181. Nonplanarity of the C14-C15 bond region along with the influence of the negatively charged counterions Glu181 and Glu113 are found to be important to reproduce the spectroscopic features of retinal chromophore inside the Rh cavity. Furthermore, the protein field is responsible for the largest bond-order decrease at the C11-C12 double bond upon excitation, which may be the reason for the 11-cis photoisomerization specificity.
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Affiliation(s)
- Ksenia Bravaya
- Department of Chemistry, M.V. Lomonosov Moscow State University, 1/3, Leninskie Gory, Moscow 119992, Russian Federation
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76
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Horsman GP, Bhowmik S, Seah SYK, Kumar P, Bolin JT, Eltis LD. The Tautomeric Half-reaction of BphD, a C-C Bond Hydrolase. J Biol Chem 2007; 282:19894-904. [PMID: 17442675 DOI: 10.1074/jbc.m702237200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BphD of Burkholderia xenovorans LB400 catalyzes an unusual C-C bond hydrolysis of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) to afford benzoic acid and 2-hydroxy-2,4-pentadienoic acid (HPD). An enol-keto tautomerization has been proposed to precede hydrolysis via a gem-diol intermediate. The role of the canonical catalytic triad (Ser-112, His-265, Asp-237) in mediating these two half-reactions remains unclear. We previously reported that the BphD-catalyzed hydrolysis of HOPDA (lambda(max) is 434 nm for the free enolate) proceeds via an unidentified intermediate with a red-shifted absorption spectrum (lambda(max) is 492 nm) (Horsman, G. P., Ke, J., Dai, S., Seah, S. Y. K., Bolin, J. T., and Eltis, L. D. (2006) Biochemistry 45, 11071-11086). Here we demonstrate that the S112A variant generates and traps a similar intermediate (lambda(max) is 506 nm) with a similar rate, 1/tau approximately 500 s(-1). The crystal structure of the S112A:HOPDA complex at 1.8-A resolution identified this intermediate as the keto tautomer, (E)-2,6-dioxo-6-phenyl-hex-3-enoate. This keto tautomer did not accumulate in either the H265A or the S112A/H265A double variants, indicating that His-265 catalyzes tautomerization. Consistent with this role, the wild type and S112A enzymes catalyzed tautomerization of the product HPD, whereas H265A variants did not. This study thus identifies a keto intermediate, and demonstrates that the catalytic triad histidine catalyzes the tautomerization half-reaction, expanding the role of this residue from its purely hydrolytic function in other serine hydrolases. Finally, the S112A:HOPDA crystal structure is more consistent with hydrolysis occurring via an acyl-enzyme intermediate than a gem-diol intermediate as solvent molecules have poor access to C6, and the closest ordered water is 7 A away.
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Affiliation(s)
- Geoff P Horsman
- Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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77
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Sekharan S, Sugihara M, Weingart O, Okada T, Buss V. Protein Assistance in the Photoisomerization of Rhodopsin and 9-cis-RhodopsinInsights from Experiment and Theory. J Am Chem Soc 2007; 129:1052-4. [PMID: 17263385 DOI: 10.1021/ja066970p] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sivakumar Sekharan
- Department of Chemistry, University of Duisburg-Essen, 47048 Duisburg, Germany
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