The Protein Man's Blog | A Discussion of Protein Research

Expression of recombinant proteins with peptide or protein tags is widely used in protein research for three main reasons, ease of purification from a large pool of host proteins, enhancing solubility of the protein and for localization studies. Some important steps to be considered while choosing an expression vector are compatibility of tag sequence with that of the desired protein, codon usage, including linker sequences, peptide cleavage sites and the impact of the tag on the nature of desired protein. Various tags are used ranging from large proteins (Maltose Binding Protein {MBP}) to small peptides (Hexa (6X) Histidine). Tags can be added to either N-terminal side or C-terminal side of the desired protein.

Gene cloning is one of the most important steps in recombinant DNA Technology. Now-a- days researchers are using different cloning techniques depending on purpose, time, cost, ease of use and availability of resources.  A few of the techniques are briefly explained below.

A restriction enzyme (restriction endonuclease) is a special enzyme that recognizes a specific sequence of nucleotides and cleaves DNA at that specific site (restriction site or target sequence). These enzymes, which are usually found in bacteria and other prokaryotes, are considered as one of the most important tools in recombinant DNA technology since they can easily cut DNA into fragments and/or join DNA molecules from different genomes so researchers can identify and characterize genes and examine gene expression and regulation.

Bacteria are as interesting as they are diverse. Though tiny, these unicellular life forms make huge contributions to many systems and cycles. From helping break down food in your intestine; to making the molecular assist in all three of the carbon, phosphorus, and nitrogen cycles -- these little bacteria can accomplish big things. Unsurprisingly, bacteria are model organisms for research. Not only because of their diversity, but also because they are easily contained and reproduce quickly. When using bacteria for research, it is important to understand and track rates of bacterial growth within a sample.