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Published on: May 29, 2010
Purification of oat and rye phytochrome.
H V Rice1, W R Briggs, C J Jackson-White
1The Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138.
Plant Physiology
|May 1, 1973
Summary
This study details a new method for purifying phytochrome (a plant photoreceptor) from oat and rye seedlings. Results suggest oat phytochrome may be an artifact due to protein breakdown during isolation.
Area of Science:
- Plant molecular biology
- Photoreceptor protein research
- Biochemical purification techniques
Background:
- Phytochrome is a crucial plant photoreceptor regulating various developmental processes.
- Existing purification methods for phytochrome, particularly from oats, may yield altered protein structures.
- Understanding phytochrome heterogeneity is key to deciphering its diverse roles in plant life.
Purpose of the Study:
- To develop and compare purification protocols for phytochrome from etiolated oat and rye seedlings.
- To characterize the biochemical and electrophoretic properties of isolated oat and rye phytochrome.
- To investigate potential artifacts in previously described oat phytochrome preparations.
Main Methods:
- Chromatographic techniques including diethylaminoethyl cellulose and molecular sieve gel chromatography.
- Electrophoresis in sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) for molecular weight determination.
- Spectrophotometric analysis to determine absorbance ratios (A(280) nm/A(665) nm).
Main Results:
- High yields of oat phytochrome (20%+) with a molecular weight of 62,000 were obtained.
- Rye phytochrome exhibited different chromatographic behavior and a higher molecular weight (120,000).
- Purified rye phytochrome showed an absorbance ratio (1.25-1.37) distinct from oat phytochrome (0.78-0.85).
Conclusions:
- The distinct properties of rye phytochrome suggest it represents a more native form.
- Oat phytochrome, as previously characterized, may be an artifact resulting from proteolysis during isolation.
- Modified purification strategies are proposed to mitigate protease activity and obtain accurate phytochrome characterization.
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