Polypeptide synthesis catalyzed by p-hydroxymercuribenzoate-modified ribosomes

Area of Science:

• Molecular Biology
• Biochemistry
• Ribosome Function

Background:

• Escherichia coli ribosomes are crucial for protein synthesis.
• Understanding ribosome modification impacts molecular biology research.
• Polyphenylalanine synthesis is a model for translation studies.

Purpose of the Study:

• To investigate the effect of p-hydroxymercuribenzoate on Escherichia coli ribosome activity.
• To determine the mechanism behind ribosome stimulation or inhibition.
• To analyze changes in polyphenylalanine chain length and synthesis rate.

Main Methods:

• Modification of Escherichia coli ribosomes with varying molar ratios of p-hydroxymercuribenzoate.
• Assaying poly(U)-directed polyphenylalanine synthesis.
• Comparing average polyphenylalanine chain length and synthesis rates between treated and untreated ribosomes.

Main Results:

• Low concentrations of p-hydroxymercuribenzoate stimulate polyphenylalanine synthesis by increasing average chain length.
• High concentrations of p-hydroxymercuribenzoate inactivate approximately 50% of active ribosomes.
• Remaining active ribosomes in high-concentration treated preparations exhibit an increased synthesis rate.

Conclusions:

• Ribosome stimulation by p-hydroxymercuribenzoate is primarily due to increased polypeptide chain elongation.
• Ribosome inactivation occurs at higher reagent concentrations, with surviving ribosomes showing enhanced activity.
• These findings provide insights into the regulatory mechanisms of ribosomal protein synthesis.