0000000000391889
AUTHOR
Janne Ihalainen
UV-Vis Spectroscopy Reveals a Correlation Between Y263 and BV Protonation States in Bacteriophytochromes
Red‐light photosensory proteins, phytochromes, link light activation to biological functions by interconverting between two conformational states. For this, they undergo large‐scale secondary and tertiary changes which follow small‐scale Z to E bond photoisomerization of the covalently bound bilin chromophore. The complex network of amino acid interactions in the chromophore‐binding pocket plays a central role in this process. Highly conserved Y263 and H290 have been found to be important for the photoconversion yield, while H260 has been identified as important for bilin protonation and proton transfer steps. Here, we focus on the roles these amino acids are playing in preserving the chemi…
Strong coupling between surface plasmon polaritons and \beta-carotene in nanolayered system
In this article we experimentally demonstrate the strong coupling between surface plasmon polaritons (SPP) and the S2 state of β-carotene. The SPPs are excited by prism coupling technique on a thin silver film with β-carotene embedded in a polymer layer on top of that. Rabi splittings with energies 80 and 130 meV are observed in the recorded dispersion relations. Both coupled oscillator model and transfer matrix method are used to fit the experimental results. The scattered radiation of the propagating strongly coupled SPP-S2 hybrids is collected and an increase of the low energy splitting to 120 meV is observed compared to the reflectivity data. In addition, we performed molecule excitatio…
Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli
Bacteria possess an intricate internal organization resembling that of the eukaryotes. The complexity is especially prominent at the bacterial cell poles, which are also known to be the preferable sites for some bacteriophages to infect. Bacteriophage PRD1 is a well-known model serving as an ideal system to study structures and functions of icosahedral internal membrane-containing viruses. Our aim was to analyze the localization and interactions of individual PRD1 proteins in its native host Escherichia coli. This was accomplished by constructing a vector library for production of fluorescent fusion proteins. Analysis of solubility and multimericity of the fusion proteins, as well as their …
Fast Photochemistry of Prototypical Phytochromes : A Species vs. Subunit Specific Comparison
Phytochromes are multi-domain red light photosensor proteins, which convert red light photons to biological activity utilizing the multitude of structural and chemical reactions. The steady increase in structural information obtained from various bacteriophytochromes has increased understanding about the functional mechanism of the photochemical processes of the phytochromes. Furthermore, a number of spectroscopic studies have revealed kinetic information about the light-induced reactions. The spectroscopic changes are, however, challenging to connect with the structural changes of the chromophore and the protein environment, as the excited state properties of the chromophores are very sens…
Strong coupling between surface plasmon polaritons and β-carotene in nanolayered system.
In this article we experimentally demonstrate the strong coupling between surface plasmon polaritons (SPP) and the S(2) state of β-carotene. The SPPs are excited by prism coupling technique on a thin silver film with β-carotene embedded in a polymer layer on top of that. Rabi splittings with energies 80 and 130 meV are observed in the recorded dispersion relations. Both coupled oscillator model and transfer matrix method are used to fit the experimental results. The scattered radiation of the propagating strongly coupled SPP-S(2) hybrids is collected and an increase of the low energy splitting to 120 meV is observed compared to the reflectivity data. In addition, we performed molecule excit…
CCDC 1524052: Experimental Crystal Structure Determination
UDAKOC : diaqua-(μ-1,13-dioxa-4,7,10,16,19,22-hexaazacyclotetracosane)-bis(perchlorato)-di-copper(ii) diperchlorate tetrahydrate Space Group: P21/c, Cell: a 11.8763(3)Å b 13.9146(4)Å c 13.4024(4)Å, α 90.00° β 123.439(2)° γ 90.00° Work published 2017 via Cambridge Crystallographic Data Centre.