A plasmid is a small, circular, extrachromosomal DNA molecule found primarily in bacteria. Physically separated from chromosomal DNA, it can replicate independently. Plasmids naturally carry genes that provide organisms with advantageous traits, such as antibiotic resistance, and are widely used in genetic engineering as vectors to clone and transfer genes.

The His-tag method (polyhistidine tag) is a widely used laboratory technique in molecular biology that attaches a string of 6-10 histidine amino acids to a recombinant protein. This allows researchers to easily isolate and purify their specific protein of interest from a complex mixture of cell parts using affinity chromatography

Heterologous protein expression systems utilize foreign host organisms—like bacteria, yeast or mammalian cells to manufacture specific, recombinant proteins via introduced DNA. This critical biotechnology method allows researchers to study complex gene functions and economically mass-produce essential biopharmaceuticals.

Protein engineering is the process of modifying existing proteins or designing entirely new ones to possess highly specific, commercially valuable traits. By combining molecular biology, recombinant DNA technology and artificial intelligence, scientists create customized enzymes, antibodies and therapeutic proteins for use in medicine, industry and agriculture.