Patent ID: 8697608
Filing Date: 2014-04-15
Classification: C07K,C12N

Abstract:
1. A method of forming a library of fibronectin Type 3 (FN3) domain polypeptides useful in screening for the presence of one or more polypeptides having a selected binding or enzymatic activity, comprising (i) aligning BC, DE, and FG amino acid loop sequences in a collection of native fibronectin Type 3 domain polypeptides, (ii) segregating the aligned loop sequences according to loop length, (iii) for a selected loop and loop length from step (ii), performing positional amino acid frequency analysis to determine the frequencies of amino acids at each loop position, (iv) for each loop and loop length analyzed in step (iii), identifying at each position a conserved or selected semi-conserved consensus amino acid and other natural-variant amino acids, (v) for at least one selected loop and loop length, forming: (vi) incorporating the library of coding sequences into framework FN3 coding sequences to form an FN3 expression library, and (vii) expressing the FN3 polypeptides of the expression library, wherein all of the amino acids in the beta-strand regions A, AB, B, C, CD, D, E, EF, F, and G of said expressed FN3 polypeptides are the wildtype amino acid sequences of the 14th fibronectin Type III module of human fibronectin.