Figure 3
Interface between the 8D6 Fab and IgE-Fc. (a) The Fab heavy chain (light pink) forms a 640 Å2 interface with the Cε3 domain (blue). Trp33 (CDRH1) is sandwiched between the Pro365 and Lys391 (Cε3 domain) side chains. (b) The Fab heavy chain (green) engages the Cε2 and Cε3 domains from one IgE-Fc chain (yellow), but also contacts the Cε2-Cε3 linker from the other IgE-Fc chain (blue). Asn30 and Arg102 from the Fab are within hydrogen bonding distance of Ser331 and Asn332 (Cε2-Cε3 linker), respectively. (c) Tyr31, Tyr36 and Asn96 from the Fab light chain (dark pink) form a cleft around Arg393 (Cε3 domain, blue). (d) In a 106Å2 interface, Asp32, Gly33 and Asp34 from the Fab light chain (dark pink) contact two mannose residues (Man906 and Man907), and Asp34 forms a hydrogen bond with the α(1-2) glycosidic bond between Man906 and Man907.
