FU Berlin Digitale Dissertation
Karsten Heyne : Ultrafast dynamic protein-controlled reactions in bacteriorhodopsin and bacterial phytochrome Ultraschnelle Dynamik Protein-gesteuerter Reaktionen in Bakteriorhodopsin und bakteriellem Phytochrom
|Abstract| |Table of Contents| |More Information|

Abstract In nature chromoproteins facilitate conversion of light to biochemical energy. Thereby the specific embedding of the light absorbing chromophore in the protein binding pocket is crucial for controlling the yield and the reaction channels of light conversion. In order to understand this optimized photoreaction, we examine the impact of chromophore - protein interaction on the primary photoreaction, e. g. the femtosecond to picosecond time span the photon is absorbed and first ground state intermediates arise. In this work two biological important chromoproteins are studied: 1) Bacteriorhodopsin (bR) is a light driven proton-pump, which enables the bacterium to produce ATP and prevent from starvation by lack of energy. The primary step of light conversion is the trans-to-cis isomerization of the retinal chromophore. The dynamic of this photoreaction is catalyzed at least by a factor of 3 due to the chromophore - protein interaction in comparison to the same reaction in solution. The quantum yield is drastically increased and due to the protein all other reaction channels are suppressed. We explore specific single and double mutants to find a crucial or minimal binding pocket for the catalytic reaction. 2) Bacterial phytochrome from Cyanobacterium Synechocystis (Cph1) is discovered only a few years ago and shows large genetic homology to phytochrome of plants. Spectroscopic features are similar, so that comparison of the two phytochromes give more insight in function and chromophore - protein interaction of phytochromes. Characteristic feature of phytochromes are two thermally stable states, which show different photoreactions in the same protein binding pocket. We characterize the primary photoreaction of Cph1 and propose a model with a distribution of potential surfaces to explain our data and in respect of published data.

Table of Contents Download the whole PhDthesis as a zip-tar file or as zip-File For download in PDF format click the chapter title 0. Titelblatt, Inhaltsverzeichnis 1. Einleitung 1 1.1. Die Protonenpumpe Bakteriorhodopsin 5 1.2. Der Photorezeptor Phytochrom 10 1.3. Ultrakurzzeitspektroskopische Grundlagen 14 2. Experimentelle Methoden 27 2.1. Einleitung 27 2.2. Lasersystem 27 2.3. VIS-VIS-Spektroskopie 28 2.4. VIS-IR-Spektroskopie 46 2.5. Signaldetektion und Signalverarbeitung 54 2.6. Charakterisierung der Lichtimpulse 70 2.7. Probenpräparation 76 2.8. Probenhalter 77 2.9. Zusammenfassung 78 3. Ergebnisse und Diskussion 81 3.1. Steuerung der Primärreaktion von bR 81 3.2. Dynamik der Primärreaktion von Cph1-PEB 96 3.3. Dynamik der Primärreaktion von Cph1-PCB Pr 105 3.4. Primärreaktion von Cph1-PCB in der Pfr -Form 154 4. Zusammenfassung und Ausblick 159 A. Anhang 163 A.1. Biologische Grundlagen 163 A.2. Physikalische Grundlagen 166 A.3. Ergänzungen zur Auswertung 170 Literaturverzeichnis 193

More Information:
Online available:	http://www.diss.fu-berlin.de/2002/2/indexe.html
Language of PhDThesis:	german
Keywords:	bacteriorhodopsin, phytochrome, reaction control, isomerization, ultrafast reaction
DNB-Sachgruppe:	29 Physik, Astronomie
Date of disputation:	13-Feb-2001
PhDThesis from:	Fachbereich Physik, Freie Universität Berlin
First Referee:	Prof. Dietmar Stehlik
Second Referee:	Prof. Maarten Heyn
Contact (Author):	heyne@mbi-berlin.de
Contact (Advisor):	diller@physik.fu-berlin.de
Date created:	10-Dec-2001
Date available:	04-Jan-2002

 

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