Characterization of Self-Assembled Monolayers of Peptide Mimotopes of XXXX Antigen and Their Binding with Rituximab.

@entity462 @entity706 @entity534 @entity20740 @entity1892 @entity1778 @entity367 @entity6346 @entity792 @entity12950
UNASSIGNED: @entity12950 , expressed on greater than 90% of @entity1892 , is a target for antibody therapy. Rituximab is a chimeric monoclonal antibody against the protein @entity12950 , allowing it to destroy B cells and to treat @entity706 , @entity1778 , transplant rejection, and @entity792 . In this work, the binding of Rituximab with @entity20740 ( @entity20740 ) of peptide mimotopes of @entity12950 antigen was systematically characterized. Four peptide mimotopes of @entity12950 were selected from literature and redesigned to allow their @entity20740 immobilizations on gold electrodes through a peptide linker with @entity462 . The bindings of these peptides with Rituximab and control antibodies (Trastuzumab, and Bevacizumab) were characterized by Quartz Crystal Microbalance (QCM). Among the four peptide mimotopes initially selected, the peptide designated as CN-14 (CGSGSGSWPRWLEN) was the most selective and sensitive for Rituximab binding. The CN-14 @entity20740 was further characterized by ellipsometry and atomic force microscopy. The thickness of the CN-14 @entity20740 film was approximately 32    and the CN-14 @entity20740 is suggested to be stabilized by a salt bridge of @entity534 -10 and GLU-13 between CN-14 peptides. The CN-14 salt bridge was evaluated by a series of modifications to the CN-14 peptide sequence and characterized by QCM. The CN-14 @entity6346 variant produced a better affinity to Rituximab than that of CN-14 without a significant impact on selectivity. As the @entity367 residue pKa of CN-14 increased, the affinity of the @entity20740 to Rituximab increased while the selectivity decreased. This was attributed to the weakening of the salt bridge between the CN-14 ARG-10 and GLU-13 at higher pKa values for GLU-13. Our study shows that peptide mimotopes have potential benefit in sensor applications as the peptide-peptide interactions in the @entity20740 could be manipulated by the addition of functional groups to the peptide to influence binding of the target protein.
