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Controlling Structural and Functional Features of Photosynthetic Antenna

100%

Fiedor L., Fiedor J., Pilch M., Susz A., Tworzydło J., Michalik M.

Acta Physica Polonica A

2012

vol. 122

issue 2

255-258

In order to gain control over the assembly and functioning of photosynthetic antenna, we have developed methods to manipulate pigment composition of bacterial LH1 complexes via their reconstitution with modified bacteriochlorophylls or carotenoids, major photoactive cofactors of these antennae. In the present work we show how the reconstitution and pigment exchange approach is applied to control structural and functional parameters of LH1 and its subunits. The size of the subunits and the energy of the first excited singlet state can be controlled via the use of detergent while the thermodynamics of LH1 formation can be modified using carotenoids and/or a co-solvent. Carotenoids affect the efficiency of the intracomplex energy transfer, while the replacement of native bacteriochlorophyll a with its Ni-substituted analog allows one to control the excited state properties of LH1. These results show that LH1 is a very promising model system applicable for the design of bio-inspired device performing solar energy conversion.

Protein Structure and Function in the Time-Domain of Vibrational Spectroscopies. The Promising Applications of IR Synchrotron Radiation Micro-Spectroscopy

88%

Marcelli A.

Acta Physica Polonica A

2006

vol. 109

issue 3

287-304

Fourier Transform Infrared (FTIR) spectroscopy is a fundamental technique capable to characterize proteins and to investigate their conformation and dynamics in real physiological environments. Actually, a FTIR spectrum is characterized by many features, which may be correlated to the different components of the protein structure. In the last decade many relevant results have been achieved with this technique in terms of chemical imaging of proteins at subcellular level and in the investigation of cooperative phenomena. This contribution presents a few examples that illustrate the capability of the FTIR spectroscopy to investigate both protein structure and function and the opportunities offered by IR synchrotron radiation sources. Indeed the high source brilliance of these sources enables FTIR micro-spectroscopy to be performed with spatial and time resolution not available with standard sources. Moreover, the combination of synchrotron radiation and new two-dimensional detectors open new opportunities to investigate in the IR energy domain different protein processes in real time and with proteins in their native environments.

Quantum Foundations of Resonant Recognition Model

75%

Keković G., Raković D., Tošić B., Davidović D., Cosić I.

issue 5

756-759

Biomolecular recognition is an open scientific problem, which has been investigated in many theoretical and experimental aspects. In that sense, there are encouraging results within Resonant Recognition Model (RRM), based on the finding that there is a significant correlation between spectra of the numerical presentation of amino acids in the primary structure of proteins and their biological activity. It has been found through an extensive research that proteins with the same biological function have a common frequency in their numerical spectra. This frequency was found then to be a characteristic feature for protein biological function or interaction The RRM model proposes that the selectivity of protein interactions is based on resonant energy transfer between interacting biomolecules and that this energy, electromagnetic in its nature, is in the frequency range of 10^{13} to 10^{15} Hz, which incorporates infra-red (IR), visible and a small portion of the ultra-violet (UV) radiation. In this paper, the quantum mechanical basis of the RRM model will be investigated using the solution in the simplified framework of Hückel-like theory of molecular orbits.

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3 Acta Physica Polonica A

1 2012

1 2010

1 2006

1 Cosić I.

1 Davidović D.

1 Fiedor J.

1 Fiedor L.

1 Keković G.

1 Marcelli A.

1 Michalik M.

1 Pilch M.

1 Raković D.

1 Susz A.

1 Tošić B.

1 Tworzydło J.

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Controlling Structural and Functional Features of Photosynthetic Antenna

Protein Structure and Function in the Time-Domain of Vibrational Spectroscopies. The Promising Applications of IR Synchrotron Radiation Micro-Spectroscopy

Quantum Foundations of Resonant Recognition Model