Dissociation of polysome aggregates by protease k

Area of Science:

• Molecular Biology
• Plant Biochemistry
• Zea mays L. research

Background:

• Zein proteins are crucial storage proteins in maize (Zea mays L.) kernels.
• Polysomes, complexes of mRNA and ribosomes, synthesize proteins.
• Understanding polysome structure is key to elucidating protein synthesis regulation.

Purpose of the Study:

• To investigate the nature of large zein-synthesizing polysomes in developing maize kernels.
• To determine the role of Protease K in altering polysome size.
• To differentiate between protein aggregation and ribonuclease activity affecting polysome structure.

Main Methods:

• Treatment of polysomes from developing Zea mays L. kernels with Protease K.
• Analysis of polysome size reduction.
• Assessment of ribonuclease activity using free polysomes and mRNA.
• Use of high MgCl(2) concentrations to study protein interactions.

Main Results:

• Protease K treatment converted large zein-synthesizing polysomes into smaller ones.
• The observed reduction in polysome size was not attributed to ribonuclease activity.
• High MgCl(2) concentrations appeared to induce protein interactions among nascent zein polypeptides.
• Protease K inhibited protein synthesis capacity but proved useful for detecting protein-mediated polysome aggregation.

Conclusions:

• Protease K is a valuable tool for identifying protein-aggregated polysomes.
• Zein polysome size can be influenced by protein interactions, not solely mRNA length.
• This study clarifies the factors affecting polysome structure and function in maize kernel development.