Patent ID: 6428954
Filing Date: 2002-08-06
Classification: A61P,C07K,C12N,C40B,G01N,Y10S

Abstract:
A method for identifying at least a first unknown active domain in a region of known amino acid sequence of a parent polypeptide, which parent polypeptide has been cloned and has a pre-identified biological activity, said active domain capable of interacting with a first target when said parent polypeptide is in its native-folded form, which interaction is responsible for said biological activity, said method comprising:(a) comparing amino acid sequence or polypeptide structure in the region of known amino acid sequence of the parent polypeptide with amino acid sequence or polypeptide structure in a region of known amino acid sequence of an analog polypeptide to said parent polypeptide, said analog having at least 15% sequence homology with said parent polypeptide or &agr;-carbon coordinates within about 2 to about 3.5 Ã¥ of parent polypeptide &agr;-carbon coordinates for about 60% or more of the analog sequence, wherein any interaction of said analog with said first target is different from the interaction of said parent polypeptide with said first target; (b) substituting DNA encoding a first analogous polypeptide segment from said analog into DNA encoding substantially the full-length parent polypeptide and expressing a first segment-substituted polypeptide; (c) contacting said first segment-substituted polypeptide with said first target to determine the interaction, if any, between said first target and said segment-substituted polypeptide; (d) repeating steps (b) and (c) using a second analogous polypeptide segment from an analog to said parent polypeptide to form at least a second segment-substituted polypeptide containing said second analogous polypeptide segment, which is different from said first analogous polypeptide segment; and (e) comparing the difference, if any, between the activity relative to said first target of said parent polypeptide and said first and second segment-substituted polypeptides as an indication of the location of said first unknown active domain in said parent polypeptide.