Proteins catalyzing the extension of plant cell walls

US5990283A · kind A · utility

Assignee

• The Penn State Research Foundation · US

Inventors

• Daniel J. Cosgrove · State College, US
• Simon McQueen-Mason · Fulford, GB

Key dates

• Filing date: Apr 15, 1997
• Grant date: Nov 23, 1999
• Expiry date: Apr 15, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A40/146
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

Plant cell expansion is regulated by wall relaxation and yielding, which is thought to be catalyzed by elusive "wall loosening" enzymes. By employing a reconstitution approach, we initially found that a crude protein extract from the cell walls of growing cucumber seedlings possessed the ability to induce the extension of isolated cell walls. This activity was restricted to the growing region of the stem and could induce the extension of isolated cell walls from various dicots and monocots, but was less effective on grass coleoptile walls. Sequential HPLC fractionation of the active wall extract revealed two proteins with molecular masses of 29 and 30 kD, as measured by SDS-PAGE, associated with such activity. Each protein, by itself, could induce wall extension without detectable hydrolytic breakdown of the wall We proposed the name "expansins" for this class of proteins. Expansins have been isolated from various plant sources including oat, cucumber, broccoli, celery, tomato, cotton, cabbage, and corn, and also from snail and its feces. These proteins weaken the intermolecular bonds between plant wall polysaccharides. They decrease the mechanical strength of commercial products m…