Kevin E. Redding - US grants

With this award from the Major Research Instrumentation (MRI) Program, the Department of Chemistry at the University of Alabama in Tuscaloosa will acquire a High Field (W-Band) Electron Paramagnetic Resonance (EPR) Spectrometer. Among the research programs in which EPR spectroscopy will play a vital role are: a) the study of carotenoids as radical scavengers; b) the mechanism of formation of mesoporous silicas; c) use of molecular genetics and high-field EPR to identify and characterize the binding site of the phylloquinone cofactor in Photosystem I; d) ferromagnetic resonance studies of high-anisotropy magnetic media; e) studies of biologically-relevant first row transition metal assemblies; and f) EPR spectroscopy of localized radical cations within redox-gradient dendrimers.

An electron paramagnetic resonance (EPR) spectrometer is an instrument used to obtain information about the molecular and electronic structure of molecules. It may also be used to obtain information about the lifetimes of free radicals which are often essential for the initiation of tumor growth and/or a variety of chemical reactions. These studies will have an impact in a number of areas, especially materials science and biochemistry.

With support from the Chemistry Research Instrumentation and Facilities (CRIF) Program, the Department of Chemistry at the University of Alabama in Tuscaloosa will acquire a nanosecond transient absorption spectrometer. Research will focus on photoinduced electron transfer studies, including a) measurement of electron transfer rates in redox-gradient dendrimers; b) use of fast spectroscopy to understand the phylloquinone cofactor in Photosystem I; and c) investigations of photochemistry in novel chromophores for optical data storage.

Transient absorption spectroscopy is an extremely versatile tool that can be used to probe fundamental photophysical and photochemical processes. These studies will have an impact in a number of areas including materials science and biochemistry.

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand how membrane protein complexes are disassembled and degraded. Many proteins are degraded in a regulated and energy-consuming fashion, and proteins recognized by the cell as aberrant are targeted by these "quality control" systems preferentially. Although the cellular mechanisms used to degrade soluble proteins are becoming well understood, knowledge of the corresponding process for membrane proteins has lagged, despite the key role many membrane proteins play in important processes, such as signal transduction, bioenergetics, and cellular homeostasis. Several human diseases, such as cystic fibrosis and retinitis pigmentosa, are caused by degradation of membrane proteins with point mutations. The model system proposed here is the Photosystem I (PS1) complex in the unicellular green alga, Chlamydomonas reinhardtii. This protein is an essential part of the photosynthetic electron transport chain and uses light absorbed by its associated chlorophyll molecules to drive electron transfer across the thylakoid membrane. It should serve as an excellent model substrate for membrane protein degradation, because the functional portion of the protein is in the plane of the membrane, where it has many spectroscopic probes built into it. The project makes use of the complementary approaches of suppressor genetics and biochemistry. The specific aims of the proposed continuation project are (1) to finish genetic characterization of a set of suppressor mutations that display decreased efficiency of degradation of PS1, (2) to clone a representative suppressor mutation using molecular map-based techniques, and (3) to create a biochemical complementation system and use it for the purification of protein(s) involved in targeting and degrading PS1.

With support from the Chemistry Research Instrumentation and Facilities (CRIF) Program, the Department of Chemistry at the University of Alabama in Tuscaloosa will acquire an Electron Paramagnetic Resonance (EPR) Spectrometer. Some of the studies that will exploit this instrument include a) the structure of intermediates upon photoionization of carotenoids in mesoporous molecular sieves; b) formation of porous materials; c) ligand bridges on tetra-nuclear chromium assemblies within the insulin-signaling chromodulin oligopeptide; and d) interactions of the protein with electron transfer cofactors of Photosystem I.

An electron paramagnetic resonance (EPR) spectrometer is an instrument used to obtain information about the molecular and electronic structure of molecules. It may also be used to obtain information about the lifetimes of free radicals, which are often essential for the initiation of tumor growth and/or a variety of chemical reactions. These studies will have an impact in a number of areas, in particular biological chemistry.

The Chemistry Department at the University of Alabama Tuscaloosa will acquire a liquid chromatograph mass spectrometer (LC-MS) with this award from the Chemistry Research Instrumentation and Facilities: Multi User (CRIF:MU) program. The requested LC-MS will facilitate ongoing research projects including: cofactor identification and proteomic analysis of photosynthetic systems; elucidation of the role of chromium in human metabolism and its implications in insulin sensitivity and treatments of diabetes; the development of water-soluble ligands for aqueous-phase catalysis and studies of metal-catalyzed modification of nucleosides; preparation and characterization of pentafluorosulfanyl-benzenes and fluorinated polymers for use in a range of industrial applications; and fundamental and applied studies into the sequencing of metallopeptides and deprotonated peptides.

Mass spectroscopy is a basic tool used by physical and biological scientists to identify and characterize materials and chemical species by accurate measurement of their mass as they are vaporized and fragmented in the instrument. Liquid chromatography is a purification technique that separates a complex mixture into individual components before introduced to the mass spectrometer. These are important tools to be used in the training of young scientists. Over 60 student researchers will use LC-MS in their research projects over the next few years. This includes graduate students, undergraduate academic year and summer students (including students from UA's NSF REU program), and high school teachers participating in summer programs. Through the use of an autosampler and cyber-control, educators and researchers located at 4 or more regional undergraduate institutions including two minority serving institutions, will have access to the instrument for the purposes of laboratory classes and undergraduate research.