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Small molecular weight GTP-binding proteins in human erythrocyte ghosts
Biochemical and Biophysical Research Communications
|October 31, 1988
Summary
Researchers identified two small molecular weight G proteins in human erythrocyte ghosts. One is ras protein, and the other is a novel 22 kDa G protein (22K G) with specific guanosine triphosphate binding capabilities.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Guanine nucleotide-binding proteins (G proteins) are crucial signal transducers.
- Human erythrocyte ghosts are a valuable model for studying membrane-associated proteins.
Purpose of the Study:
- To identify and characterize small molecular weight G proteins in human erythrocyte ghosts.
- To determine the binding properties and potential novel nature of these G proteins.
Main Methods:
- Extraction of G proteins using sodium cholate.
- Purification via Ultrogel AcA-44 gel filtration and hydroxyapatite column chromatography.
- Further purification and molecular weight determination using Mono Q HR5/5 chromatography and SDS-PAGE.
Main Results:
- Two distinct G protein peaks were separated by hydroxyapatite chromatography.
- The second peak contained ras protein and G proteins recognized by anti-alpha subunits of Gs and Gi.
- The first peak yielded a novel 22 kDa G protein (22K G) that specifically binds GTP analogs and GTP, with inhibition by N-ethylmaleimide.
Conclusions:
- Human erythrocyte ghosts contain at least two species of small molecular weight G proteins.
- One identified G protein is the ras protein.
- A novel 22 kDa G protein (22K G) with specific GTP-binding properties was discovered in human erythrocytes.