4 + 4 Defence by Sune Klamer Jørgensen – Niels Bohr Institute - University of Copenhagen

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4 + 4 Defence by Sune Klamer Jørgensen

Upon light absorption the membrane protein-pigment complex, Photosystem I (PSI), produces electrons with the highest reducing potential in biology, and transfers them across the membrane. The unique properties of PSI have made it an object of intense study in many branches of natural science. The majority of studies however have been performed in bulk and therefore cannot identify putative heterogeneities of individual PSI complexes due to ensemble averaging. Here we aim to employ single molecule techniques that can investigate the properties of individually addressed PSI, which could yield hitherto hidden information on the function and mechanism of PSI.

Herein we describe the development of three different platforms for single molecule measurements on PSI: The first platform seeks to end-to-end link gold nanorods with single PSI via self-assembly in order to incorporate PSI in a nanoelectronic circuit, thus allowing for molecular electronics measurements on PSI. The second platform aims to develop a single PSI activity assay with control of the microenvironment via PSI proteoliposomes with prefluorescent reporters encapsulated. The purpose of the third platform is to incorporate individually separated PSI complexes in Langmuir-Blodgett lipid films to increase stability of dry PSI, and allow for scanning probe investigations of single PSI.

The progress made, the obstacles encountered, and methods to overcome these obstacles will be presented and discussed.

4 + 4 Defence by Sune Klamer Jørgensen