THROUGH-SPACE ELECTRON TRANSFER REACTIONS

  • Lewis, Nita A. (PI)

Project: Research project

Project Details

Description

One of the unresolved problems in the study of electron transfer mechanisms
involves the methods of electron transport on a molecular level in the
respiratory chain. Our objective is to construct models which will mimic
the electronic pathways available for long distance transfers in proteins.
An examination of simple systems and of proteins whose structures are well
known (especially cytochrome c) leads us to postulate that electron rich
functional groups such as aromatic rings and sulfur atoms may serve to
mediate and guide the transferring electron. The approach to be used is
quite original in that we assume that geometry of the metal in relation to
that of the sulfur and aromatic ring is a critical factor in observing
through-space interactions in proteins and that this preferred geometry can
be found by an examination of the properties of simple model systems. At
the same time, we propose to investigate small molecules designed to
transfer electrons in a 'through-bond' manner. There is evidence from
photoelectron spectroscopy that this occurs. Its importance in biological
systems can only be assessed if quantitative data from simple well-defined
systems are available. The methods used to explore the redox process will
be primarily electrochemistry and near-infrared spectroscopy. The latter
technique will be employed to measure the intervalence transition band
which appears when an electron is optically transferred from one metal to
another in the same molecule. The shape and intensity of the band provides
information on the degree of electronic coupling between the metal
centers. In the long-term, the model studies will serve to direct the
approach to a study of the actual proteins since one might expect to
observe intervalence transitions indicative of through-space interactions
in proteins under the proper experimental conditions, yet to be determined.
StatusFinished
Effective start/end date12/31/896/30/90

Funding

  • National Institute of General Medical Sciences
  • National Institute of General Medical Sciences
  • National Institute of General Medical Sciences
  • National Institute of General Medical Sciences

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