Mouse Anti-AAPP Recombinant Antibody (clone 8H7) (CAT#: HPAB-S0186-YC)

The region of AAPP involved in collagen binding has been tested previously by expression of recombinant truncated genes carrying different combinations of the four exons making up the coding sequence. Exons 3 and 4, which encode residues 148–204 and 205–269, respectively, were found to be absolutely required for collagen binding, and the full-length protein binds soluble collagen with similar affinity to AAPPex3–4. To locate the site of collagen interaction more accurately, several mutants of GST-fused AAPPex3–4 were produced including a multiple mutant with Lys 232, Asp-233, Lys-234, and Asn-235 changed to alanines (termed "4A"), Cys-239 to alanine (termed "C3"), and both Cys-239 and Cys 261 to alanines (termed "C3/C4"). The pulldown assay demonstrated that the 8H7 bound to wild-type AAPPex3–4 but not to 4A or C3, further confirming that the 8H7 Fab binds to the turn region between helices. The loss of interaction if one cysteine residue is mutated to alanine suggests that the tertiary structure of the loop region is also required for tight binding of AAPP to the 8H7.