Related Experiment Videos
Hemoglobin in Frankia, a nitrogen-fixing actinomycete
John D Tjepkema1, Robert E Cashon, Jason Beckwith
1Department of Biological Sciences, University of Maine, Orono, Maine 04469-5722, USA. tjepkema@maine.edu
Applied and Environmental Microbiology
|April 27, 2002
Summary
Frankia strain CcI3 produces a novel hemoglobin. This hemoglobin exhibits typical optical properties and a molecular mass of 14.1 kDa, with specific oxygen binding kinetics.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Frankia are nitrogen-fixing bacteria crucial for plant symbiosis.
- Hemoglobins in bacteria play roles in oxygen transport and detoxification.
- Understanding Frankia hemoglobin function is key to optimizing symbiotic processes.
Purpose of the Study:
- To characterize the hemoglobin produced by Frankia strain CcI3 in culture.
- To determine the biochemical and kinetic properties of this bacterial hemoglobin.
Main Methods:
- Culturing Frankia strain CcI3 under specific conditions.
- Spectroscopic analysis to determine optical absorption bands.
- Biophysical techniques to measure molecular mass and oxygen binding kinetics.
Main Results:
- Frankia strain CcI3 produced a hemoglobin with optical absorption bands characteristic of hemoglobins.
- The hemoglobin's molecular mass was determined to be 14.1 kDa.
- Key kinetic parameters were quantified: equilibrium oxygen binding constant (274 nM), oxygen dissociation rate constant (56 s(-1)), and oxygen association rate constant (206 microM(-1) s(-1)).
Conclusions:
- Frankia strain CcI3 synthesizes a functional hemoglobin in vitro.
- The characterized kinetic parameters provide insights into the hemoglobin's oxygen-binding capabilities.
- This finding contributes to the understanding of oxygen metabolism in Frankia symbionts.