FIGURE 4.

Definition and functional analyses of HCII-derived peptides. (A) Illustration of HCII structure. Exposed helical peptide regions are indicated: helix A, GKS26 (green); helix D, KYE28 (orange); helix H, SGM22 (magenta); helix F, SDP18 (cyan); and helix C, LKG23 (yellow). (B) Slot blot assay for detection of binding of the indicated HCII-derived peptides to ¹²⁵I-labeled LPS in the presence or absence of heparin. (C) Antimicrobial activity of HCII peptides against E. coli in 10 mM Tris, 0.15 M NaCl, with or without 20% citrate plasma. Bacterial survival (%) is presented as mean values ± SEM (n = 3). (D) Analysis of permeabilizing effects of HCII-derived peptides. E. coli bacteria were incubated with the indicated peptides and permeabilization assessed using the impermeant probe FITC. Top panel: Nomarski images; bottom panel: fluorescence microscopy images of the same view fields (original magnification ×100).