Biomaterial Database

Regions located in both the N-lobe and C-lobe of human lactoferrin participate in the binding interaction with bacterial lactoferrin receptors. 1993

R H Yu, and A B Schryvers

Department of Microbiology and Infectious Diseases, University of Calgary, Alberta, Canada.

As a first step in localizing the regions of human lactoferrin involved in binding to bacterial lactoferrin receptors, N-lobe and C-lobe fragments were assessed for binding to receptors on Neisseria meningitidis, Neisseria gonorrhoeae and Moraxella (Branhamella) catarrhalis. Preparations of N-lobe and C-lobe were obtained by tryptic digestion of iron-loaded human lactoferrin followed by separation of the two lobes by gel exclusion chromatography in 10% acetic acid. Solid phase binding studies demonstrated that the isolated C- and N-lobe preparations were capable of binding to membranes from iron-deficient N. meningitidis, N. gonorrhoeae and M. catarrhalis. The binding of the individual C- and N-lobes was confirmed by an analytical SDS-PAGE binding method in which the membrane-associated polypeptides were identified by prior biotinylation and subsequent binding of labelled streptavidin. This contrasts with bacterial transferrin receptors, which only bind to C-lobe fragment of human transferrin, indicating that the bacterial lactoferrin and transferrin receptors differ in their interaction with their respective glycoprotein ligands and may differ in the mechanism of iron removal.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007781	Lactoferrin	An iron-binding protein that was originally characterized as a milk protein. It is widely distributed in secretory fluids and is found in the neutrophilic granules of LEUKOCYTES. The N-terminal part of lactoferrin possesses a serine protease which functions to inactivate the TYPE III SECRETION SYSTEM used by bacteria to export virulence proteins for host cell invasion.	Lactotransferrin
D009344	Neisseria gonorrhoeae	A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.	Diplococcus gonorrhoeae,Gonococcus,Gonococcus neisseri,Merismopedia gonorrhoeae,Micrococcus der gonorrhoe,Micrococcus gonococcus,Micrococcus gonorrhoeae
D009345	Neisseria meningitidis	A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.	Diplokokkus intracellularis meningitidis,Meningococcus,Micrococcus intracellularis,Micrococcus meningitidis,Micrococcus meningitidis cerebrospinalis,Neisseria weichselbaumii
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D001936	Moraxella catarrhalis	Gram-negative aerobic cocci of low virulence that colonize the nasopharynx and occasionally cause MENINGITIS; BACTEREMIA; EMPYEMA; PERICARDITIS; and PNEUMONIA.	Branhamella catarrhalis,Mikrokkokus catarrhalis,Moraxella (Branhamella) catarrhalis
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man