Abstract:
The present invention relates to a method for manufacturing a mutant library of proteins with various sizes and sequences from a parental protein, microorganisms transformed with plasmids containing recombinant DNAs prepared by the insertion of a genomic DNA fragment into a defective template, a process for preparing proteins with different sizes and sequences from the parental protein which comprises the steps of culturing the transformed microorganisms and obtaining desired proteins from the culture, and proteins prepared by the said process. In accordance with the invention, a mutant library of proteins with various sizes and sequences can be manufactured from a parental protein in an efficient and simple manner, by constructing a library of microorganisms transformed with recombinant plasmids containing E. coli genomic DNA fragments inserted into defective genes and selecting clones expressing proteins with restored functions or modified characteristics.