Distance and Potential Dependence of Charge Transport Through the Reaction Center of Individual Photosynthetic Complexes

Small ◽  
2021 ◽  
pp. 2104366
Author(s):  
Manuel López‐Ortiz ◽  
Ricardo A. Zamora ◽  
Marina Inés Giannotti ◽  
Chen Hu ◽  
Roberta Croce ◽  
...  
Keyword(s):  
Charge Transport ◽  
Reaction Center ◽  
Potential Dependence ◽  
Photosynthetic Complexes

scholarly journals Reaction Center of Rhodobacter Sphaeroides, a Photoactive Protein for pH Sensing: A Theoretical Investigation of Charge Transport Properties

2021 ◽  
Author(s):  
Eleonora Alfinito ◽  
Lino Reggiani
Keyword(s):  
Charge Transport ◽  
Transport Properties ◽  
Reaction Center ◽  
Theoretical Investigation ◽  
Rhodobacter Sphaeroides ◽  
Electronic Devices ◽  
Ph Sensing ◽  
Biological Matter

Featured Application: Bio-electronic devices take advantages of some specific duties of biological matter. The specific ability of some proteins to use sunlight is considered for the realization of photo-electronic devices . Here the focus is on the role of the pH, whose variations seem to affect the protein conductance

scholarly journals Redox Probing Study of the Potential Dependence of Charge Transport Through Li2O2

2015 ◽  
Vol 119 (51) ◽  
pp. 28292-28299 ◽  
Author(s):  
Kristian B. Knudsen ◽  
Alan C. Luntz ◽  
Søren H. Jensen ◽  
Tejs Vegge ◽  
Johan Hjelm
Keyword(s):  
Charge Transport ◽  
Potential Dependence

scholarly journals Distance and Potential Dependence of Charge Transport Through the P700 Reaction Center of Photosystem I

2021 ◽  
Author(s):  
Manuel López Ortiz ◽  
Ricardo A Zamora ◽  
Marina Inés Giannotti ◽  
Chen Hu ◽  
Roberta Croce ◽  
...  
Keyword(s):  
Charge Transport ◽  
Reaction Center ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Hole Injection ◽  
Scanning Tunneling ◽  
Potential Range ◽  
Tunneling Microscopy ◽  
Spatial Span ◽  
Probe Potential

Photoinduced charge separation and transport through photosystem I (PSI) is an essential part of the photosynthetic electron transport chain. To investigate charge exchange processes mediated by the P700 reaction center of PSI, we have developed a strategy to functionalize gold electrodes with PSI complexes that orients and exposes their luminal side to the electrolyte. Bulk photoelectrochemical measurements demonstrate that PSI remains functional in a wide sample potential range around 0 mV/SSC. Electrochemical scanning tunneling microscopy (ECSTM) imaging of individual complexes shows lateral sizes in agreement with the dimensions of PSI and an apparent height that is gated by the probe potential of ECTSM as reported for smaller globular redox proteins. This experimental setup enables ECSTM current-distance spectroscopic measurements that unequivocally correspond to the P700 side of PSI. In these conditions, we observe that the spatial span of the current is enhanced (the distance-decay rate β is reduced) through the solution at sample potential 0 mV/SSC and probe potential 400 mV/SSC. This process corresponds to hole injection into an electronic state that is available in the absence of illumination. We propose that a pair of tryptophan residues located near P700 and known to integrate the hydrophobic recognition site for plastocyanin may have an additional role as hole exchange mediator involved in charge transport through PSI.<br>

scholarly journals Distance and Potential Dependence of Charge Transport Through the P700 Reaction Center of Photosystem I

2021 ◽  
Author(s):  
Manuel López Ortiz ◽  
Ricardo A Zamora ◽  
Marina Inés Giannotti ◽  
Chen Hu ◽  
Roberta Croce ◽  
...  
Keyword(s):  
Charge Transport ◽  
Reaction Center ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Hole Injection ◽  
Scanning Tunneling ◽  
Potential Range ◽  
Tunneling Microscopy ◽  
Spatial Span ◽  
Probe Potential

Photoinduced charge separation and transport through photosystem I (PSI) is an essential part of the photosynthetic electron transport chain. To investigate charge exchange processes mediated by the P700 reaction center of PSI, we have developed a strategy to functionalize gold electrodes with PSI complexes that orients and exposes their luminal side to the electrolyte. Bulk photoelectrochemical measurements demonstrate that PSI remains functional in a wide sample potential range around 0 mV/SSC. Electrochemical scanning tunneling microscopy (ECSTM) imaging of individual complexes shows lateral sizes in agreement with the dimensions of PSI and an apparent height that is gated by the probe potential of ECTSM as reported for smaller globular redox proteins. This experimental setup enables ECSTM current-distance spectroscopic measurements that unequivocally correspond to the P700 side of PSI. In these conditions, we observe that the spatial span of the current is enhanced (the distance-decay rate β is reduced) through the solution at sample potential 0 mV/SSC and probe potential 400 mV/SSC. This process corresponds to hole injection into an electronic state that is available in the absence of illumination. We propose that a pair of tryptophan residues located near P700 and known to integrate the hydrophobic recognition site for plastocyanin may have an additional role as hole exchange mediator involved in charge transport through PSI.<br>

scholarly journals Long-range light-modulated charge transport across molecular heterostructures doped protein biopolymers

2021 ◽  
Author(s):  
Somen Mandal ◽  
Nadav Amdursky ◽  
Nandan Ghorai ◽  
Hirendra N. Ghosh ◽  
SOUMYADIP BHUNIA
Keyword(s):  
Electron Transfer ◽  
Charge Transport ◽  
Reaction Center ◽  
Long Range ◽  
Charge Separation ◽  
Induced Charge

Electron transfer (ET) across proteins is ubiquitous in nature, such as the notable photosynthesis example, where light-induced charge separation takes place within the reaction center, followed by sequential ET via...

Cytochemical Localization of Polysaccharides in Diplodia Maydis With Thiosemicarbazide : Evaluation of Three Fixatives For Pa:Tsc:Os Reaction

1976 ◽  
Vol 34 ◽  
pp. 48-49 ◽  
Author(s):  
Judith A. Murphy ◽  
Mary R. Thompson ◽  
A.J. Pappelis
Keyword(s):  
Reaction Center ◽  
Osmium Tetroxide ◽  
Periodic Acid ◽  
Cytochemical Localization ◽  
Thin Sections ◽  
Selective Reaction ◽  
Amorphous Character

In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.

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