The metH gene from Salmonella typhimurium LT2: cloning and initial characterization

Area of Science:

• Molecular Biology
• Microbial Genetics
• Gene Expression Analysis

Background:

• The metH gene in Salmonella typhimurium encodes a crucial enzyme in methionine biosynthesis.
• Understanding gene structure and expression is vital for microbial metabolic engineering.

Purpose of the Study:

• To clone and characterize the Salmonella typhimurium metH gene in Escherichia coli.
• To determine the size, transcriptional direction, and estimated translation start/stop sites of the metH gene product.

Main Methods:

• Cloning of a 19-kb EcoRI DNA fragment containing the metH gene into the pACYC184 plasmid vector.
• Propagation of the recombinant plasmid in Escherichia coli K-12.
• Analysis of plasmid-specific polypeptides using SDS-polyacrylamide gel electrophoresis in a minicell system.
• Determination of gene transcription direction and estimation of translation initiation and termination positions.

Main Results:

• Successful cloning and propagation of the Salmonella typhimurium metH gene in E. coli.
• The metH gene product was identified as approximately 120 kDa via SDS-PAGE.
• The direction of metH gene transcription relative to the cloned fragment was established.
• Estimated positions for translation initiation and termination were determined.

Conclusions:

• The metH gene from Salmonella typhimurium has been successfully cloned and characterized in E. coli.
• Key molecular parameters of the metH gene, including product size and expression direction, have been elucidated.
• This study provides essential molecular data for further investigations into methionine biosynthesis pathways.