       Document 0052
 DOCN  M9640052
 TI    Use of a novel mutagenesis strategy, optimized residue substitution, to
       decrease the off-rate of an anti-gp120 antibody.
 DT    9604
 AU    Lewis CM; Hollis GF; Mark GE 3rd; Tung JS; Ludmerer SW; Merck Research
       Laboratories, Rahway, NJ 07065, USA.
 SO    Mol Immunol. 1995 Oct;32(14-15):1065-72. Unique Identifier : AIDSLINE
       MED/96128275
 AB    We have developed a novel strategy to decrease the antibody:antigen
       off-rate which we call optimized residue substitution. This strategy
       employs alanine substitution to first identify residues non-optimal for
       binding, as evidenced by a decrease in off-rate upon alanine
       replacement. These positions are then individually randomized to all
       amino acids, and the best replacement for each position determined.
       Finally, a construct which combines all optimized substitutions is
       generated and evaluated. We applied this strategy to the heavy chain
       CDR3 of P5Q, a scFv antibody which recognizes an epitope on the V3 loop
       of HIV gp120. We identified two amino acid substitutions that together
       decrease the off-rate by nearly ten-fold. The contributions by the two
       substitutions were near additive, indicative of independent affects on
       binding. We suggest that this strategy can be generalized to strengthen
       protein:ligand and protein:protein interactions in other systems.
 DE    Alanine/GENETICS  Amino Acid Sequence  *Antibody Affinity  Base Sequence
       Binding Sites, Antibody  Binding, Competitive/IMMUNOLOGY  HIV
       Antibodies/*BIOSYNTHESIS/*GENETICS  HIV Envelope Protein
       gp120/*GENETICS/*IMMUNOLOGY  Immunoglobulin Variable
       Region/CHEMISTRY/GENETICS  Immunoglobulins,
       Heavy-Chain/CHEMISTRY/GENETICS  Molecular Sequence Data  Mutagenesis,
       Insertional/*IMMUNOLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

