Groenhof, Gerrit

[["dc.bibliographiccitation.firstpage","6812"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","Journal of the American Chemical Society"],["dc.bibliographiccitation.lastpage","6819"],["dc.bibliographiccitation.volume","129"],["dc.contributor.author","Groenhof, Gerrit"],["dc.contributor.author","Schäfer, Lars V."],["dc.contributor.author","Boggio-Pasqua, Martial"],["dc.contributor.author","Goette, Maik"],["dc.contributor.author","Grubmüller, Helmut"],["dc.contributor.author","Robb, Michael A."],["dc.date.accessioned","2018-04-23T11:47:47Z"],["dc.date.available","2018-04-23T11:47:47Z"],["dc.date.issued","2007"],["dc.description.abstract","Multiconfigurational ab initio calculations and QM/MM molecular dynamics simulations of a photoexcited cytosine−guanine base pair in both gas phase and embedded in the DNA provide detailed structural and dynamical insights into the ultrafast radiationless deactivation mechanism. Photon absorption promotes transfer of a proton from the guanine to the cytosine. This proton transfer is followed by an efficient radiationless decay of the excited state via an extended conical intersection seam. The optimization of the conical intersection revealed that it has an unusual topology, in that there is only one degeneracy-lifting coordinate. This is the central mechanistic feature for the decay both in vacuo and in the DNA. Radiationless decay occurs along an extended hyperline nearly parallel to the proton-transfer coordinate, indicating the proton transfer itself is not directly responsible for the deactivation. The seam is displaced from the minimum energy proton-transfer path along a skeletal deformation of the bases. Decay can thus occur anywhere along the single proton-transfer coordinate, accounting for the remarkably short excited-state lifetime of the Watson−Crick base pair. In vacuo, decay occurs after a complete proton transfer, whereas in DNA, decay can also occur much earlier. The origin of this effect lies in the temporal electrostatic stabilization of dipole in the charge-transfer state in DNA."],["dc.identifier.doi","10.1021/ja069176c"],["dc.identifier.gro","3142268"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/13396"],["dc.language.iso","en"],["dc.notes.intern","lifescience updates Crossref Import"],["dc.notes.status","final"],["dc.relation.issn","0002-7863"],["dc.title","Ultrafast Deactivation of an Excited Cytosine−Guanine Base Pair in DNA"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","530"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Angewandte Chemie International Edition"],["dc.bibliographiccitation.lastpage","536"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Schäfer, Lars V."],["dc.contributor.author","Groenhof, Gerrit"],["dc.contributor.author","Klingen, Astrid R."],["dc.contributor.author","Ullmann, G. Matthias"],["dc.contributor.author","Boggio-Pasqua, Martial"],["dc.contributor.author","Robb, Michael A."],["dc.contributor.author","Grubmüller, Helmut"],["dc.date.accessioned","2017-09-07T11:52:29Z"],["dc.date.available","2017-09-07T11:52:29Z"],["dc.date.issued","2007"],["dc.description.abstract","Molecular light‐switch: Off–on switching of the fluorescence of the protein asFP595 involves a trans–cis isomerization. Mixed quantum/classical simulations elucidate the spectroscopic properties of asFP595 and give detailed insights into the photoswitching mechanism. The conformational trans–cis switching triggers a proton‐transfer cascade between the chromophore and adjacent amino acids."],["dc.identifier.doi","10.1002/ange.200602315"],["dc.identifier.gro","3144945"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/2626"],["dc.language.iso","en"],["dc.notes.intern","Crossref Import"],["dc.notes.status","final"],["dc.publisher","Wiley-Blackwell"],["dc.relation.issn","1433-7851"],["dc.title","Photoswitching of the Fluorescent Protein asFP595: Mechanism, Proton Pathways, and Absorption Spectra"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3250"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Journal of the American Chemical Society"],["dc.bibliographiccitation.lastpage","3251"],["dc.bibliographiccitation.volume","130"],["dc.contributor.author","Groenhof, Gerrit"],["dc.contributor.author","Schäfer, Lars V."],["dc.contributor.author","Boggio-Pasqua, Martial"],["dc.contributor.author","Grubmüller, Helmut"],["dc.contributor.author","Robb, Michael A."],["dc.date.accessioned","2018-02-13T12:55:37Z"],["dc.date.available","2018-02-13T12:55:37Z"],["dc.date.issued","2008-03-19"],["dc.description.abstract","We have performed excited-state dynamics simulations of the Arg52Gln (R52Q) mutant of photoactive yellow protein (PYP). The results of these simulations demonstrate that in the mutant the primary events after photoexcitation are different from those in the wild-type. In the mutant, the chromophore predominantly undergoes single bond photoisomerization, whereas in the wild-type, photoisomerization of the double bond occurs. Furthermore, the excited-state lifetime is around three times longer than in wild-type PYP, which agrees well with recent transient absorption measurements. In 20% of the trajectories, we observe the formation of a photoproduct that has the carbonyl oxygen atom of the chromophore flipped by almost 180°, disrupting the hydrogen bond between the chromophore and the backbone amino group of Cys69. This observation, in combination with the fact that the mutant is photoactive, suggests that the break of the hydrogen bond is the key step in the photoactivation process rather than the double bond trans-to-cis isomerization."],["dc.identifier.doi","10.1021/ja078024u"],["dc.identifier.pmid","18293978"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12226"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1520-5126"],["dc.title","Arginine52 controls the photoisomerization process in photoactive yellow protein"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","10996"],["dc.bibliographiccitation.issue","36"],["dc.bibliographiccitation.journal","Journal of the American Chemical Society"],["dc.bibliographiccitation.lastpage","10997"],["dc.bibliographiccitation.volume","129"],["dc.contributor.author","Boggio-Pasqua, Martial"],["dc.contributor.author","Groenhof, Gerrit"],["dc.contributor.author","Schäfer, Lars V."],["dc.contributor.author","Grubmüller, Helmut"],["dc.contributor.author","Robb, Michael A."],["dc.date.accessioned","2018-04-23T11:47:46Z"],["dc.date.available","2018-04-23T11:47:46Z"],["dc.date.issued","2007"],["dc.identifier.doi","10.1021/ja073628j"],["dc.identifier.gro","3142265"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/13393"],["dc.language.iso","en"],["dc.notes.intern","lifescience updates Crossref Import"],["dc.notes.status","final"],["dc.relation.issn","0002-7863"],["dc.title","Ultrafast Deactivation Channel for Thymine Dimerization"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e1000034"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","PLoS Computational Biology"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Schäfer, Lars V."],["dc.contributor.author","Groenhof, Gerrit"],["dc.contributor.author","Boggio-Pasqua, Martial"],["dc.contributor.author","Robb, Michael A."],["dc.contributor.author","Grubmüller, Helmut"],["dc.contributor.editor","Warshel, Arieh"],["dc.date.accessioned","2018-02-13T13:16:24Z"],["dc.date.available","2018-02-13T13:16:24Z"],["dc.date.issued","2008-03-21"],["dc.description.abstract","Fluorescent proteins have been widely used as genetically encodable fusion tags for biological imaging. Recently, a new class of fluorescent proteins was discovered that can be reversibly light-switched between a fluorescent and a non-fluorescent state. Such proteins can not only provide nanoscale resolution in far-field fluorescence optical microscopy much below the diffraction limit, but also hold promise for other nanotechnological applications, such as optical data storage. To systematically exploit the potential of such photoswitchable proteins and to enable rational improvements to their properties requires a detailed understanding of the molecular switching mechanism, which is currently unknown. Here, we have studied the photoswitching mechanism of the reversibly switchable fluoroprotein asFP595 at the atomic level by multiconfigurational ab initio (CASSCF) calculations and QM/MM excited state molecular dynamics simulations with explicit surface hopping. Our simulations explain measured quantum yields and excited state lifetimes, and also predict the structures of the hitherto unknown intermediates and of the irreversibly fluorescent state. Further, we find that the proton distribution in the active site of the asFP595 controls the photochemical conversion pathways of the chromophore in the protein matrix. Accordingly, changes in the protonation state of the chromophore and some proximal amino acids lead to different photochemical states, which all turn out to be essential for the photoswitching mechanism. These photochemical states are (i) a neutral chromophore, which can trans-cis photoisomerize, (ii) an anionic chromophore, which rapidly undergoes radiationless decay after excitation, and (iii) a putative fluorescent zwitterionic chromophore. The overall stability of the different protonation states is controlled by the isomeric state of the chromophore. We finally propose that radiation-induced decarboxylation of the glutamic acid Glu215 blocks the proton transfer pathways that enable the deactivation of the zwitterionic chromophore and thus leads to irreversible fluorescence. We have identified the tight coupling of trans-cis isomerization and proton transfers in photoswitchable proteins to be essential for their function and propose a detailed underlying mechanism, which provides a comprehensive picture that explains the available experimental data. The structural similarity between asFP595 and other fluoroproteins of interest for imaging suggests that this coupling is a quite general mechanism for photoswitchable proteins. These insights can guide the rational design and optimization of photoswitchable proteins."],["dc.identifier.doi","10.1371/journal.pcbi.1000034"],["dc.identifier.pmid","18369426"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12230"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1553-7358"],["dc.title","Chromophore protonation state controls photoswitching of the fluoroprotein asFP595"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]