Receptors for transferrin in pathogenic bacteria are specific for the host's protein

1990 ◽  
Vol 36 (2) ◽  
pp. 145-147 ◽  
Author(s):  
Anthony B. Schryvers ◽  
Guido C. Gonzalez
Keyword(s):  
Transferrin Receptor ◽  
Pathogenic Bacteria ◽  
Binding Assay ◽  
Solid Phase ◽  
Actinobacillus Pleuropneumoniae ◽  
Pasteurella Haemolytica ◽  
Transferrin Receptors ◽  
Iron Deficient ◽  
Key Words Iron ◽  
Solid Phase Binding

Transferrin receptors detected by a solid-phase binding assay were shown to be specific for the host's transferrin in the representative bacterial pathogens Neisseria meningitidis (human), Pasteurella haemolytica (bovine), and Actinobacillus pleuropneumoniae (porcine). Consistent with the receptor specificity, iron-deficient bacteria were only capable of utilizing transferrin from the host as a source of iron for growth. Key words: iron, transferrin, receptor.

Interaction between the pili of Pseudomonas aeruginosa PAK and its carbohydrate receptor β-D-GalNAc(1->4) β-D-Gal analogs

1998 ◽  
Vol 44 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Frank Schweizer ◽  
Hailong Jiao ◽  
Ole Hindsgaul ◽  
Wah Y Wong ◽  
Randall T Irvin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Binding Assay ◽  
Solid Phase ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Surface Receptors ◽  
Order Of Magnitude ◽  
Epithelial Cell Surface ◽  
Solid Phase Binding

Pseudomonas aeruginosa employs pili to mediate adherence to epithelial cell surface receptors. Previously, it has been shown that the pilus adhesin of P. aeruginosa PAK binds to the ganglioside asialo-GM1. In particular, it was found that the carbohydrate sequence β-D-GalNAc(1->4) β-D-Gal is the minimal carbohydrate receptor sequence of asialo-GM1. To study the binding specificity of P. aeruginosa, O-modified and N-modified sugar analogs, where each hydroxyl group was substituted either by O-methyl or O-propyl and the acetamido group was changed to a propionamido group, were synthesized. The sugar analogs were evaluated as inhibitors in a competitive solid phase binding assay. The results demonstrate that the pili of P. aeruginosa PAK accepts a variety of sugar analogs possessing the sequence β-D-GalNAc(1->4) β-D-Gal. Most sugar analogs bind with a similar order of magnitude (50% inhibitory concentration (IC50) = 60-130 μM) except for the 2-O-propyl derivative 7 (IC50 = 8 ± 4 μM) compared with an IC50 of 79 ± 18 μM for the native compound. The significant increase in binding affinity of 2-O-propyl derivative 7 suggests that improved inhibitors of adhesion may be prepared by introducing a hydrophobic side chain at the 2-position of galactose.Key words: Pseudomonas aeruginosa, pili, adhesion, carbohydrate.

Production of transferrin receptors byHistophilus ovis: three of five strains require two signals

2001 ◽  
Vol 47 (5) ◽  
pp. 417-423 ◽  
Author(s):  
Andrew Ekins ◽  
Donald F Niven
Keyword(s):  
Solid Phase ◽  
Iron Acquisition ◽  
Isolation Procedure ◽  
Transferrin Receptors ◽  
Binding Assays ◽  
Surface Receptors ◽  
Iron Restriction ◽  
Affinity Isolation ◽  
Solid Phase Binding ◽  
Bovine Transferrin

Five strains of Histophilus ovis (9L, 642A, 714, 5688T, and 3384Y) were investigated with respect to iron acquisition. All strains used ovine, bovine, and goat transferrins (Tfs), but not porcine or human Tfs, as iron sources for growth. In solid phase binding assays, total membranes from only two (9L and 642A) of the five strains, grown under iron-restricted conditions, were able to bind Tfs (ovine, bovine, and goat, but not porcine or human). However, when the organisms were grown under iron-restricted conditions in the presence of bovine transferrin (Tf), total membranes from all strains exhibited Tf binding (as above); competition experiments demonstrated that all three Tfs (ovine, bovine, and goat) were bound by the same receptor(s). Membranes from organisms grown under iron-replete conditions in the presence or absence of bovine Tf failed to bind any of the test Tfs. An affinity-isolation procedure allowed the isolation of two putative Tf-binding polypeptides (78 and 66 kDa) from total membranes of strains 9L and 642A grown under iron-restricted conditions, and from membranes of all strains if the growth medium also contained Tf. It is concluded that all strains tested acquire Tf-bound iron by means of siderophore-independent mechanisms involving surface receptors analogous to the Tf-binding proteins (TbpA and TbpB) found in comparable organisms; although iron restriction alone is sufficient to promote the expression of these proteins by strains 9L and 642A, their production by strains 714, 5688T, and 3384Y appears to require two signals, iron restriction and the presence of Tf.Key words: Histophilus ovis, iron acquisition, transferrins, receptors, regulation.

A survey of interactions made by the giant protein titin

1993 ◽  
Vol 104 (1) ◽  
pp. 119-123 ◽  
Author(s):  
A. Soteriou ◽  
M. Gamage ◽  
J. Trinick
Keyword(s):  
Binding Assay ◽  
Solid Phase ◽  
Myofibrillar Protein ◽  
Amp Deaminase ◽  
Sarcomeric Proteins ◽  
X Protein ◽  
C Protein ◽  
Protein X ◽  
Solid Phase Binding

A simple solid-phase binding assay was used to screen for interactions that the giant myofibrillar protein titin makes with other sarcomeric proteins. The titin used in the tests was purified by a modified procedure that results in isolation of approximately 20 mg relatively undegraded protein in < 24 h. In addition to the approximately 3 MDa polypeptide, bands at approximately 160 kDa and approximately 100 kDa were also consistently seen on gels. Binding of titin to myosin, C-protein, X-protein and AMP-deaminase was observed. The interaction with myosin appears to be with the light meromyosin part of the molecule.

scholarly journals Evidence of widespread binding of HLA class I molecules to peptides.

1990 ◽  
Vol 172 (3) ◽  
pp. 827-834 ◽  
Author(s):  
J A Frelinger ◽  
F M Gotch ◽  
H Zweerink ◽  
E Wain ◽  
A J McMichael
Keyword(s):  
Monoclonal Antibodies ◽  
Binding Assay ◽  
Solid Phase ◽  
Hla Class I ◽  
Class I ◽  
T Cell Epitopes ◽  
Single Class ◽  
Hla Class I Molecules ◽  
Solid Phase Binding ◽  
Hiv 1

We have tested the binding of HLA class I proteins to peptides using a solid-phase binding assay. We tested 102 peptides, mostly derived from the HIV gag and HIV pol sequences. Most peptides did not bind to any class I protein tested. The pattern of binding among the three class I proteins tested, HLA-A2, -B27, and -B8, was approximately 85% concordant. Further, all five of the known HIV-1 gag T cell epitopes detected by human CTL bound at least one class I protein. Binding of class I to the peptides could be detected either by directly iodinated class I proteins, or indirectly using monoclonal antibodies specific for class I. The binding to the plates could be blocked with MA2.1, which binds in the alpha 1 region of A2, but not by W6/32, which binds elsewhere. The data presented here show that binding of class I to peptides is specific, but that many peptides bind to more than a single class I protein.

A simple, solid-phase binding assay for the nuclear import receptor karyopherin α. Part 1: direct binding

2000 ◽  
Vol 10 (9) ◽  
pp. 951-954 ◽  
Author(s):  
Michael D. Connolly ◽  
Seung Bum Park ◽  
Brian M. Reedy ◽  
Robert F. Standaert
Keyword(s):  
Nuclear Import ◽  
Binding Assay ◽  
Solid Phase ◽  
Direct Binding ◽  
Solid Phase Binding ◽  
Import Receptor

Turbidimetric assay of IgG with use of single monoclonal antibodies.

1986 ◽  
Vol 32 (5) ◽  
pp. 752-757 ◽  
Author(s):  
Y Maynard ◽  
M G Scott ◽  
M H Nahm ◽  
J H Ladenson
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Binding Assay ◽  
Solid Phase ◽  
Polyclonal Antiserum ◽  
Turbidimetric Assay ◽  
Group 2 ◽  
Solid Phase Binding ◽  
Low Ionic Strength ◽  
Group 1

Abstract We describe a turbidimetric assay for quantifying total immunoglobulin G (IgG) in serum with use of a single monoclonal antibody. The reaction, monitored by a centrifugal analyzer, is technically simple, rapid, and precise. Buffer of low ionic strength and polyethylene glycol are required for formation of detectable antibody-antigen complexes. We measured IgG concentrations in 49 polyclonal sera (Group 1) and 84 sera containing monoclonal IgG (Group 2) in assays in which we used either of two anti-IgG monoclonal antibodies (HG6 or HG8). Results compared well with those obtained with a nephelometric assay involving polyclonal antiserum, except for sera from four persons of Group 2 whose immunoglobulins were not detected by antibody HG6. HG6 bound IgG from these four sera in a solid-phase binding assay. HG6 and HG8 recognize epitopes on the Fab and Fc regions of IgG, respectively, and they do not compete for binding to the whole molecule. However, use of the two monoclonal antibodies combined failed to improve the sensitivity or range of the assay. We conclude that light-scattering assays of IgG can be validly performed with a single monoclonal antibody.

scholarly journals N-Terminal Domain of the Murine Coronavirus Receptor CEACAM1 Is Responsible for Fusogenic Activation and Conformational Changes of the Spike Protein

2004 ◽  
Vol 78 (1) ◽  
pp. 216-223 ◽  
Author(s):  
Hideka S. Miura ◽  
Keiko Nakagaki ◽  
Fumihiro Taguchi
Keyword(s):  
Conformational Changes ◽  
Binding Assay ◽  
Solid Phase ◽  
Hepatitis Virus ◽  
Biological Activities ◽  
Protein S ◽  
Spike Protein ◽  
Soluble Form ◽  
S Protein ◽  
Solid Phase Binding

ABSTRACT The mouse hepatitis virus (MHV) receptor (MHVR), CEACAM1, has two different functions for MHV entry into cells: binding to MHV spike protein (S protein) and activation of the S protein to execute virus-cell membrane fusion, the latter of which is accompanied by conformational changes of the S protein. The MHVR comprising the N-terminal and fourth domains [R1(1,4)] displays these two activities, and the N domain is thought to be critical for binding to MHV. In this study, we have addressed whether or not the N domain alone is sufficient for these activities. We examined three types of soluble form MHVR (soMHVR), one consisting of the N domain alone [soR1(1)], one with the N and second domains [soR1(1,2)], and one [soR1(1,4)] expressed by recombinant baculoviruses. We assessed the abilities of these three types of soMHVR to bind to MHV, activate fusogenicity, and induce conformational changes of the S protein. All three types of soMHVR similarly bound to MHV, as examined by a solid-phase binding assay and neutralized MHV infectivity. They also activated S protein fusogenicity and induced its conformational changes with similar levels of efficiency. However, R1(1) expressed on the BHK cell surface failed to serve as a receptor in spite of a sufficient level of expression. The inability of expressed R1(1) to work as a receptor was due to the inaccessibility of virions to R1(1); however, these were accessible using the MHVR-specific monoclonal antibody CC1. These results collectively indicated that the N domain retains all biological activities necessary for receptor function.

Sign in / Sign up

Export Citation Format

Share Document