[Prokaryotic expression and characterization of rice Rac protein osRACB].

Area of Science:

• Biochemistry
• Molecular Biology
• Plant Science

Background:

• Rac genes are crucial signal GTP-binding proteins in plants, acting as molecular switches.
• Understanding specific Rac proteins like osRACB is key to deciphering plant life activity regulations.

Purpose of the Study:

• To investigate the biochemical characteristics of the rice Rac protein, osRACB.
• To determine its GTP-binding and hydrolysis activities and compare them with another rice Rac protein, osRACD.

Main Methods:

• Cloning the osRACB coding sequence into an expression vector (pET28a) for expression in E. coli.
• Purification of His-osRACB fusion protein using Ni(2+)-NTA chromatography.
• Enzymatic assays to assess GTP-binding and hydrolysis activity, including Mg(2+) regulation.

Main Results:

• Successfully expressed and purified active osRACB protein.
• osRACB demonstrated significant GTP-binding and hydrolysis activity, modulated by Mg(2+).
• Compared to osRACD, osRACB displayed stronger GTP-binding but weaker GTP hydrolysis activity.

Conclusions:

• osRACB possesses distinct biochemical properties regarding GTP binding and hydrolysis.
• These findings contribute to understanding the functional diversity within rice Rac proteins and their roles in plant signaling.