Characterization of the Interaction of Photo-Generated Cob(I)inamide with Carbon Dioxide in Anaerobic Aqueous Solution Pubblico
Jawdat, BenMaan I. (2010)
Published
Abstract
Abstract
Characterization of the Interaction of Photo-Generated
Cob(I)inamide with
Carbon Dioxide in Anaerobic Aqueous Solution
By BenMaan I. Jawdat
One of the greatest challenges facing today's scientists is the
creation of a viable
renewable energy system to meet the demands of a growing
population. The use of
solar energy is currently a research focus. The long-term goal of
this project is to
develop a light-driven catalytic module in a re-engineered protein,
that will be used for
conversion of carbon dioxide (CO2) to a stable fuel in
aqueous solution. The selected
protein is the EutB protein from ethanolamine ammonia-lyase, which
contains the
native, cobalt-containing cobalamin cofactor. In this project, the
reactivity of the free
cobinamide (modified cobalamin) molecule with CO2 is
studied in buffered aqueous
solution, outside of the protein environment. Static and
time-resolved ultraviolet
(UV)/visible spectroscopy is used to characterize the cobinamide in
the absence and
presence of CO2. The fully-reduced cob(I)inamide, was
generated by photoreduction of
methylcob(III)inamide with 5'-deazariboflavin/EDTA in anaerobic,
buffered (pH=6.0)
solution. The subsequent cob(I)inamide decay reaction was measured
by the loss of
absorbance at 387 nm, with and without CO2 in solution.
An assay was developed, in
which the photolysis of methylcobalamin, and the subsequent
reaction of the
cob(II)alamin photoproduct with oxygen (O2) to form
AquoCbl, was used to quantify
the oxygen content in the samples. The careful control of pH and
exclusion of oxygen
led to dramatic improvement in the reproducibilty of the
cob(I)inamide reaction
measurements, relative to previous attemps. Decay of cob(I)inamide
in the absence of
CO2 (τ=9.0 min) was assigned to a proton reduction
reaction. Increased time constants
for decay of cob(I)inamide (up to τ=13.5 min) were observed in
the presence of CO2.
We propose that the effect is caused by the interaction of
CO2 with cob(I)inamide.
Table of Contents
Table of Contents
Chapter
Page
I.
Introduction
1
II.
Experimental Procedures
5
- Absorption Spectroscopy
5- Photolysis Studies
5- Preparation of MeCbi Samples
6- Fitting of the Cob(I)inamide Decay Kinetics
8 III. Results- Absorption Spectra of Different Cobalamin and Cobinamide Redox States
- Assay for the Determination of Oxygen Concentration in the Samples
- Reaction of Cob(I)inamide in Aqueous Solution at pH 6.0
- Reaction of Cob(I)inamide with CO2 in Aqueous Solution at pH 6.0
9 9 11 14 15 IV. Discussion 20- Establishment of Reliability and Reproducibility in Cobalamin/ Cobinamide - CO2 Reactivity Measurements
20- Dihydrogen Formation
21- CO2 Binding Interaction with Cob(I)inamide
22- Future Experiments and Outlook
23 V. References 25About this Honors Thesis
School | |
---|---|
Department | |
Degree | |
Submission | |
Language |
|
Research Field | |
Parola chiave | |
Committee Chair / Thesis Advisor | |
Committee Members |
Primary PDF
Thumbnail | Title | Date Uploaded | Actions |
---|---|---|---|
|
Characterization of the Interaction of Photo-Generated Cob(I)inamide with Carbon Dioxide in Anaerobic Aqueous Solution () | 2018-08-28 10:40:40 -0400 |
|
Supplemental Files
Thumbnail | Title | Date Uploaded | Actions |
---|