The protein engineering is an important tool to produce superior enzymes and storage proteins. To do this, a protein engineer is required to prepare a computer aided protein model for a specific function and then prepare a synthetic gene that will produce this desired protein in a pre-decided and predictable manner. Using the technique of ‘site directed mutagenesis’, changes are made in genes at known sites leading to the modification of function in a predetermined manner. The ‘computational and graphical tools’ allow the display and exploration of three dimensional structures of proteins. These two techniques are very useful in deciding about the three dimensional structure of protein/drug needed for a specific purpose before using recombinant DNA technology for proteins or organic synthesis for drugs.
Protein Engineering involves the following steps:
a) Preparation of a protein sample from an organism.
b) Characterization of the sample with a ligand such as enzyme-substrate, receptor-hormone or antigen-antibody interaction.
c) Analysis of the three dimensional (3-D) structure through NMR (nuclear magnetic resonance) and X-ray diffraction pattern of crystals.
d) Displaying of the 3-D structure with interactive computer graphics.
e) Processing of the information to select a novel design suitable to the required needs.
f) The desired DNA sequence which is expected to give the novel designed protein is then either synthesized or obtained by site directed mutagenesis of an available gene.
g) Introduction of the novel gene into a suitable expression system followed by it’s purification and biochemical characterization.
h) If biochemical characterization does not satisfy the earlier predicted structure, the cycle is repeated again.
According to biotechnology4u