ChemInform Abstract: The Influence of Secondary Structure on Electron Transfer in Peptides

ChemInform ◽  
2013 ◽  
Vol 44 (45) ◽  
pp. no-no
Author(s):  
Jingxian Yu ◽  
John R. Horsley ◽  
Andrew D. Abell
Keyword(s):  
Electron Transfer ◽  
Secondary Structure

scholarly journals The Influence of Secondary Structure on Electron Transfer in Peptides

2013 ◽  
Vol 66 (8) ◽  
pp. 848 ◽  
Author(s):  
Jingxian Yu ◽  
John R. Horsley ◽  
Andrew D. Abell
Keyword(s):  
Electron Transfer ◽  
Secondary Structure ◽  
Chain Length ◽  
Intramolecular Hydrogen Bonding ◽  
Electrochemical Analysis ◽  
Helical Conformation ◽  
Intramolecular Electron Transfer ◽  
Helical Structures ◽  
Redox Active ◽  
Intramolecular Hydrogen

A series of synthetic peptides containing 0–5 α-aminoisobutyric acid (Aib) residues and a C-terminal redox-active ferrocene was synthesised and their conformations defined by NMR and circular dichroism. Each peptide was separately attached to an electrode for subsequent electrochemical analysis in order to investigate the effect of peptide chain length (distance dependence) and secondary structure on the mechanism of intramolecular electron transfer. While the shorter peptides (0–2 residues) do not adopt a well defined secondary structure, the longer peptides (3–5 residues) adopt a helical conformation, with associated intramolecular hydrogen bonding. The electrochemical results on these peptides clearly revealed a transition in the mechanism of intramolecular electron transfer on transitioning from the ill-defined shorter peptides to the longer helical peptides. The helical structures undergo electron transfer via a hopping mechanism, while the shorter ill-defined structures proceeded via an electron superexchange mechanism. Computational studies on two β-peptides PCB-(β3Val-β3Ala-β3Leu)n–NHC(CH3)2OOtBu (n = 1 and 2; PCB = p-cyanobenzamide) were consistent with these observations, where the n = 2 peptide adopts a helical conformation and the n = 1 peptide an ill-defined structure. These combined studies suggest that the mechanism of electron transfer is defined by the extent of secondary structure, rather than merely chain length as is commonly accepted.

scholarly journals Amino Acid Substitutions in the Non-Ordered Ω-Loop 70–85 Affect Electron Transfer Function and Secondary Structure of Mitochondrial Cytochrome c

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 973
Author(s):  
Rita V. Chertkova ◽  
Tatyana V. Bryantseva ◽  
Nadezhda A. Brazhe ◽  
Kseniya S. Kudryashova ◽  
Victor V. Revin ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Secondary Structure ◽  
Cytochrome C ◽  
Cd Spectroscopy ◽  
Mitochondrial Cytochrome ◽  
Proposed Model ◽  
Donor And Acceptor ◽  
Cytochromes C ◽  
Spectroscopy Studies ◽  
Mitochondrial Cytochrome C

The secondary structure of horse cytochrome c with mutations in the P76GTKMIFA83 site of the Ω-loop, exhibiting reduced efficiency of electron transfer, were studied. CD spectroscopy studies showed that the ordering of mutant structure increases by 3–6% compared to that of the WT molecules due to the higher content of β-structural elements. The IR spectroscopy data are consistent with the CD results and demonstrate that some α-helical elements change into β-structures, and the amount of the non-structured elements is decreased. The analysis of the 1H-NMR spectra demonstrated that cytochrome c mutants have a well-determined secondary structure with some specific features related to changes in the heme microenvironment. The observed changes in the structure of cytochrome c mutants are likely to be responsible for the decrease in the conformational mobility of the P76GTKMIFA83 sequence carrying mutations and for the decline in succinate:cytochrome c-reductase and cytochrome c-oxidase activities in the mitoplast system in the presence of these cytochromes c. We suggest that the decreased efficiency of the electron transfer of the studied cytochromes c may arise due to: (1) the change in the protein conformation in sites responsible for the interaction of cytochrome c with complexes III and IV and (2) the change in the heme conformation that deteriorates its optimal orientation towards donor and acceptor in complexes III and IV therefore slows down electron transfer. The results obtained are consistent with the previously proposed model of mitochondrial cytochrome c functioning associated with the deterministic mobility of protein globule parts.

Shortcuts for Electron‐Transfer through the Secondary Structure of Helical Oligo‐1,2‐Naphthylenes

2019 ◽  
Vol 25 (72) ◽  
pp. 16748-16754 ◽  
Author(s):  
Alessandro Castrogiovanni ◽  
Patrick Herr ◽  
Christopher B. Larsen ◽  
Xingwei Guo ◽  
Christof Sparr ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Secondary Structure

Intramolecular Electrocatalysis of 8-Oxo-Guanine Oxidation:  Secondary Structure Control of Electron Transfer in Osmium-Labeled Oligonucleotides

2003 ◽  
Vol 42 (20) ◽  
pp. 6379-6387 ◽  
Author(s):  
Rebecca C. Holmberg ◽  
Mark T. Tierney ◽  
Patricia A. Ropp ◽  
Eric E. Berg ◽  
Mark W. Grinstaff ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Secondary Structure ◽  
Guanine Oxidation ◽  
Structure Control

Pseudopeptide Foldamers designed for photoinduced intramolecular electron transfer

RSC Advances ◽  
2015 ◽  
Vol 5 (14) ◽  
pp. 10809-10815 ◽  
Author(s):  
Lorenzo Milli ◽  
Enrico Marchi ◽  
Nicola Castellucci ◽  
Maria Teresa Indelli ◽  
Margherita Venturi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Secondary Structure ◽  
Photoinduced Electron Transfer ◽  
Intramolecular Electron Transfer ◽  
Quenching Efficiency

Hybrid foldamers equipped with a donor and an acceptor unit exhibit unexpected conformations affecting the photoinduced electron transfer ability. The donor quenching efficiency depends both on the nature and on the secondary structure of the linker.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

A light optical diffractometer for electron microscopical images operating in line

1978 ◽  
Vol 36 (1) ◽  
pp. 86-87
Author(s):  
P. Bonhomme ◽  
A. Beorchia
Keyword(s):  
Electron Microscopy ◽  
Electron Transfer ◽  
Electron Microscope ◽  
Image Converter ◽  
Coherent Light ◽  
Spatial Filters ◽  
Electron Image ◽  
Electron Microscopical ◽  
Working Parameters ◽  
Amorphous Part

We have already described (1.2.3) a device using a pockel's effect light valve as a microscopical electron image converter. This converter can be read out with incoherent or coherent light. In the last case we can set in line with the converter an optical diffractometer. Now, electron microscopy developments have pointed out different advantages of diffractometry. Indeed diffractogram of an image of a thin amorphous part of a specimen gives information about electron transfer function and a single look at a diffractogram informs on focus, drift, residual astigmatism, and after standardizing, on periods resolved (4.5.6). These informations are obvious from diffractogram but are usualy obtained from a micrograph, so that a correction of electron microscope parameters cannot be realized before recording the micrograph. Diffractometer allows also processing of images by setting spatial filters in diffractogram plane (7) or by reconstruction of Fraunhofer image (8). Using Electrotitus read out with coherent light and fitted to a diffractometer; all these possibilities may be realized in pseudoreal time, so that working parameters may be optimally adjusted before recording a micrograph or before processing an image.

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