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A developmentally regulated hydroxyproline-rich glycoprotein in maize pericarp cell walls
E E Hood1, Q X Shen, J E Varner
1Department of Biology, Washington University, St. Louis, Missouri 63130.
Plant Physiology
|May 1, 1988
Summary
Researchers identified a hydroxyproline-rich glycoprotein, PC-1, in developing maize kernels. This protein, crucial during mid-maturation, shows potential links to plant cell wall structures.
Area of Science:
- Plant Biochemistry
- Molecular Biology
- Agricultural Science
Background:
- Hydroxyproline accumulation occurs in developing maize (Zea mays L.) kernel pericarp.
- Peptidyl hydroxyproline content is highest during mid-maturation stages.
- This suggests a role for hydroxyproline-rich proteins in kernel development.
Purpose of the Study:
- To investigate the accumulation and characteristics of peptidyl hydroxyproline in maize kernel pericarp.
- To purify and characterize the hydroxyproline-rich glycoprotein involved.
- To explore the potential relationship of this glycoprotein to known plant cell wall proteins.
Main Methods:
- Analysis of hydroxyproline accumulation during maize kernel development.
- Extraction and fractionation of salt-soluble proteins from isolated cell walls.
- Purification using Cesium Chloride (CsCl) density gradients and Chromatofocusing.
- Characterization of the purified protein including molecular weight, isoelectric point, and amino acid composition.
Main Results:
- Hydroxyproline accumulation is highest at mid-maturation stages of maize kernel development.
- A specific hydroxyproline-rich glycoprotein, designated PC-1, was purified.
- PC-1 is a basic protein (pI ≥ 10.2) with a molecular weight of 65-70 kDa and a density of 1.38-1.39 g/cm³ in CsCl.
- Amino acid analysis revealed high levels of hydroxyproline, threonine, proline, lysine, and glycine.
Conclusions:
- A novel hydroxyproline-rich glycoprotein (PC-1) has been isolated from developing maize kernels.
- PC-1's characteristics suggest a role in maize kernel pericarp structure and development.
- Further research is warranted to elucidate PC-1's precise function and its relationship to dicot extensins.
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