Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins
Abstract To mimic the charge separation in functional proteins we studied flavin‐modified peptides as models. They were synthesized as oligoprolines that typically form a polyproline type‐II helix, because this secondary structure supports the electron transfer properties. We placed the flavin as ph...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2020-12-01
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| Series: | ChemistryOpen |
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| Online Access: | https://doi.org/10.1002/open.202000199 |
| _version_ | 1818058452859092992 |
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| author | Dr. Samantha Wörner Julia Leier Nadine C. Michenfelder Dr. Andreas‐Neil Unterreiner Prof. Hans‐Achim Wagenknecht |
| author_facet | Dr. Samantha Wörner Julia Leier Nadine C. Michenfelder Dr. Andreas‐Neil Unterreiner Prof. Hans‐Achim Wagenknecht |
| author_sort | Dr. Samantha Wörner |
| collection | DOAJ |
| description | Abstract To mimic the charge separation in functional proteins we studied flavin‐modified peptides as models. They were synthesized as oligoprolines that typically form a polyproline type‐II helix, because this secondary structure supports the electron transfer properties. We placed the flavin as photoexcitable chromophore and electron acceptor at the N‐terminus. Tryptophans were placed as electron donors to direct the electron transfer over 0–3 intervening prolines. Spectroscopic studies revealed competitive photophysical pathways. The reference peptide without tryptophan shows dominant non‐specific ET dynamics, leading to an ion pair formation, whereas peptides with tryptophans have weak non‐specific ET and intensified directed electron transfer. By different excitation wavelengths, we can conclude that the corresponding ion pair state of flavin within the peptide environment has to be energetically located between the S1 and S4 states, whereas the directed electron transfer to tryptophan occurs directly from the S1 state. These photochemical results have fundamental significance for proteins with flavin as redoxactive cofactor. |
| first_indexed | 2024-12-10T13:00:52Z |
| format | Article |
| id | doaj.art-999e9fecb4b74806b7716de3db57d786 |
| institution | Directory Open Access Journal |
| issn | 2191-1363 |
| language | English |
| last_indexed | 2024-12-10T13:00:52Z |
| publishDate | 2020-12-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | ChemistryOpen |
| spelling | doaj.art-999e9fecb4b74806b7716de3db57d7862022-12-22T01:47:57ZengWiley-VCHChemistryOpen2191-13632020-12-019121264126910.1002/open.202000199Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional ProteinsDr. Samantha Wörner0Julia Leier1Nadine C. Michenfelder2Dr. Andreas‐Neil Unterreiner3Prof. Hans‐Achim Wagenknecht4Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe GermanyInstitute of Physical Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 2 76131 Karlsruhe GermanyInstitute of Physical Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 2 76131 Karlsruhe GermanyInstitute of Physical Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 2 76131 Karlsruhe GermanyInstitute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe GermanyAbstract To mimic the charge separation in functional proteins we studied flavin‐modified peptides as models. They were synthesized as oligoprolines that typically form a polyproline type‐II helix, because this secondary structure supports the electron transfer properties. We placed the flavin as photoexcitable chromophore and electron acceptor at the N‐terminus. Tryptophans were placed as electron donors to direct the electron transfer over 0–3 intervening prolines. Spectroscopic studies revealed competitive photophysical pathways. The reference peptide without tryptophan shows dominant non‐specific ET dynamics, leading to an ion pair formation, whereas peptides with tryptophans have weak non‐specific ET and intensified directed electron transfer. By different excitation wavelengths, we can conclude that the corresponding ion pair state of flavin within the peptide environment has to be energetically located between the S1 and S4 states, whereas the directed electron transfer to tryptophan occurs directly from the S1 state. These photochemical results have fundamental significance for proteins with flavin as redoxactive cofactor.https://doi.org/10.1002/open.202000199chromophorestransient absorption spectroscopypeptidesproteinselectron transfer |
| spellingShingle | Dr. Samantha Wörner Julia Leier Nadine C. Michenfelder Dr. Andreas‐Neil Unterreiner Prof. Hans‐Achim Wagenknecht Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins ChemistryOpen chromophores transient absorption spectroscopy peptides proteins electron transfer |
| title | Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins |
| title_full | Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins |
| title_fullStr | Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins |
| title_full_unstemmed | Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins |
| title_short | Directed Electron Transfer in Flavin Peptides with Oligoproline‐Type Helical Conformation as Models for Flavin‐Functional Proteins |
| title_sort | directed electron transfer in flavin peptides with oligoproline type helical conformation as models for flavin functional proteins |
| topic | chromophores transient absorption spectroscopy peptides proteins electron transfer |
| url | https://doi.org/10.1002/open.202000199 |
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