Cryptic domains of a 60 kDa heat shock protein of Helicobacter pylori bound to bovine lactoferrin

• Published in: FEMS immunology and medical microbiology 1996-12, Vol.16 (3-4), p.247-255
• Main Authors: Amini, Hamid-Reza, Ascencio, Felipe, Ruiz-Bustos, Eduardo, Romero, Maria J., Wadström, Torkel
• Format: Article
• Language: English
• Subjects: Affinity chromatography; Animals; Anti-Bacterial Agents - metabolism; Bacteriology; Binding; Binding Sites; Binding, Competitive; Biological and medical sciences; Carbohydrates; Cattle; Cell surface; Chaperonin 60 - drug effects; Chaperonin 60 - metabolism; Chelates; Chymotrypsin; Distilled water; Domains; Endopeptidases - pharmacology; Ferritin; Fundamental and applied biological sciences. Psychology; Galactose; Glycoproteins; Haptoglobin; Heat shock protein; Heat shock proteins; Helicobacter pylori; Helicobacter pylori - metabolism; Humans; Hydrophobicity; IgG antibody; Immunoglobulin G; Iron; Kinetics; Lactoferrin; Lactoferrin - metabolism; Lactoferrin‐binding protein; Lactose; Microbiology; Nickel; Nickel sulfate; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Pepsin; Peroxidase; Protein Binding; Rhamnose; Scatchard curves
• ISSN: 0928-8244; 1574-695X; 2049-632X
• DOI: 10.1111/j.1574-695X.1996.tb00143.x

Abstract Bovine lactoferrin binds to a 60 kDa heat shock protein of Helicobacter pylori. Binding ability was related to human immunoglobulin G because bovine lactoferrin binding proteins were isolated by extraction of cell surface associated proteins with distilled water, applied on IgG-Sepharose and nickel sulphate chelate affinity chromatography. Binding was demonstrated by Western blot after purified protein was digested with α-chymotrypsin and incubated with peroxidase-labeled bovine lactoferrin. Binding was inhibited by bovine lactoferrin, lactose, rhamnose, galactose, and two iron-containing proteins, ferritin and haptoglobin. Helicobacter pylori binds ferritin and haptoglobin via charge or hydrophobic interactions because this binding was not inhibited by specific and various glycoproteins or carbohydrates. Carbohydrate moieties of bovine lactoferrin molecules seem to be involved in binding because glycoproteins with similar carbohydrate structures strongly inhibited binding. Scatchard plot analysis of the binding of peroxidase-labeled bovine lactoferrin to H. pylori cells yielded a kd 2.88 × 10−6 M. In addition, binding of H. pylori cells to bovine lactoferrin was enhanced when bacteria treated with pepsin or α-chymotrypsin after isolation from iron-restricted and iron-containing media.