scholarly journals Binding of various ovotransferrin fragments to chick-embryo red cells

1989 ◽  
Vol 257 (1) ◽  
pp. 301-304 ◽  
Author(s):  
A Oratore ◽  
G D'Andrea ◽  
K Moreton ◽  
J Williams
Keyword(s):  
Amino Acid ◽  
Chick Embryo ◽  
Red Blood Cells ◽  
Receptor Binding ◽  
Blood Cells ◽  
Tight Binding ◽  
Red Cells ◽  
Transferrin Receptors ◽  
Amino Acid Residues

1. The ability of N- and C-terminal half-molecule fragments of hen ovotransferrin to interact with chick red blood cells (CERBC) has been studied under conditions that allow binding of the transferrin to transferrin receptors to take place, but not the delivery of iron to the cell. Two kinds of half-molecule fragments were used: (a) those which can associate with one another to give a dimer resembling native transferrin and (b) those which cannot associate in this way because they lack a few amino acid residues from their C-terminal ends. 2. Neither N nor C half-molecules alone can bind to the CERBC, but, when both are present, tight binding occurs. 3. Whether or not the half-molecules can associate with one another makes little difference to receptor binding. 4. Given that one of the half-molecules is iron-saturated, the presence or absence of iron in the contralateral half-molecule again makes little difference to receptor binding.

Hemoglobin oxidation at functional amino acid residues during routine storage of red blood cells

Transfusion ◽  
2015 ◽  
Vol 56 (2) ◽  
pp. 421-426 ◽  
Author(s):  
Matthew Wither ◽  
Monika Dzieciatkowska ◽  
Travis Nemkov ◽  
Pavel Strop ◽  
Angelo D'Alessandro ◽  
...  
Keyword(s):  
Amino Acid ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Amino Acid Residues ◽  
Hemoglobin Oxidation

Characterisation of Amino Acid Transport in Red Blood Cells of a Primitive vertebrate, the Pacific Hagfish (Eptatretus Stouti)

1990 ◽  
Vol 154 (1) ◽  
pp. 355-370 ◽  
Author(s):  
DARON A. FINCHAM ◽  
MICHAEL W. WOLOWYK ◽  
JAMES D. YOUNG
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Red Blood Cells ◽  
Amino Acid Transport ◽  
Blood Cells ◽  
Red Cells ◽  
Acid Transport ◽  
Intracellular Amino Acid ◽  
Alanine Transport ◽  
The Pacific

Intracellular amino acid levels and the characteristics of amino acid transport were investigated in red blood cells of a primitive vertebrate, the Pacific hagfish (Eptatretus stouti Lockington). In contrast to red cells from euryhaline teleosts and elasmobranchs, which contain high concentrations of β-amino acids, those from hagfish exhibited an intracellular amino acid pool (approx. lOOmmoll−1cell water) composed almost entirely of conventional aαamino acids. Red cell:plasma distribution ratios for individual amino acids ranged from 219, 203 and 173 for alanine, αaminonbutyrate and proline, respectively, to 11 and 13 for lysine and arginine. Corresponding distribution ratios for Na+, K+ and Cl− were 0.043, 21 and 0.32, respectively. The cellular uptake of amino acids, with the exception of Lproline and glycine, was Na+-independent. Compared with mammalian and avian red cells, those from hagfish exhibited 104-fold higher rates of L-alanine transport. Uptake of this amino acid from the extracellular medium was concentrative, but occurred as a 1:1 exchange with intracellular amino acids. The L-alanine transport mechanism was identified as an asc-type system on the basis of its Na+ independence and selectivity for neutral amino acids of intermediate size. A volume-sensitive amino acid channel, which is found in both euryhaline teleosts and in elasmobranchs, is absent from hagfish red cells.

scholarly journals Differential effect of iodination of ovotransferrin and its two half-molecule domains on binding to transferrin receptors on chick embryo red blood cells

1987 ◽  
Vol 247 (2) ◽  
pp. 417-425 ◽  
Author(s):  
A B Mason ◽  
S A Brown
Keyword(s):  
Chick Embryo ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Solid Phase ◽  
Free Ligand ◽  
Transferrin Receptors ◽  
Apparent Dissociation Constant ◽  
Receptor Recognition ◽  
Chloramine T ◽  
Peptide Maps

Iodination of the C-terminal half-molecule domain of ovotransferrin (OTF) causes a significant reduction in binding to transferrin receptors on chick reticulocytes when compared to the binding observed with holo-OTF or the N-terminal half-molecule domain. (In such studies binding of iodinated half-molecule is measured in the presence of equimolar unlabelled complementary half-molecule). In particular iodination of the C-terminal half-molecule domain by the solid-phase reagent Iodogen resulted in half the binding found when ICl was used. The iodinated N-terminal half-molecule domain labelled by either Iodogen or ICl showed consistently higher binding than was observed with the C-terminal half-molecule or Fe2OTF. Although the molecular basis for the reduced binding of these proteins relative to the N-terminal half-molecule has not been definitively established, the implication is that there is a Tyr in the C-terminal domain which is involved in receptor recognition and binding. Addition of one or more bulky iodine atoms to the Tyr interferes with the interaction. Tryptic peptide maps of unlabelled holo-OTF and half-molecule domains and of the half-molecule domains labelled by both ICl and Iodogen are presented. The maps indicate limited access of the tyrosine residues to iodination especially in the C-terminal half-molecule domain. Equilibrium binding experiments have been carried out to compare the Kd (the apparent dissociation constant for the interaction between OTF and the transferrin receptors on chick-embryo red blood cells) with the Bmax, (binding at infinite free-ligand concentration) for Fe2OTF labelled using ICl, Iodogen, Enzymobeads and Chloramine-T. The effect of labelling Fe2OTF by Bolton-Hunter reagent has also been assessed. These studies show that ICl appears to be the reagent of choice for labelling Fe2OTF and its half-molecule domains.

HEMOLYTIC DISEASE OF THE NEWBORN DUE TO ANTI-A AND ANTI-B

PEDIATRICS ◽  
1955 ◽  
Vol 15 (1) ◽  
pp. 54-62
Author(s):  
Clare N. Shumway ◽  
Gerald Miller ◽  
Lawrence E. Young
Keyword(s):  
B Cells ◽  
Red Blood Cells ◽  
Blood Group ◽  
Newborn Infant ◽  
Blood Cells ◽  
Osmotic Fragility ◽  
Red Cells ◽  
Hemolytic Disease ◽  
Abo Incompatibility

Ten infants with hemolytic disease of the newborn due to ABO incompatibility were studied. In every case the investigations were undertaken because of jaundice occurring in the first 24 hours of life. The clinical, hematologic and serologic observations in the infants and the serologic findings in the maternal sera are described. Evidence is presented to show that the diagnosis of the disorder rests largely upon the demonstration of spherocytosis, increased osmotic fragility of the red cells, reticulocytosis, and hyperbilirubinemia in a newborn infant whose red blood cells are incompatible with the maternal major blood group isoantibody and against whose cells no other maternal isoantibody is demonstrable. The anti-A or anti-B in each of the maternal sera tested in this series hemolyzed A or B cells in the presence of complement. Other serologic findings in the maternal sera were less consistently demonstrated.

ReaxFF-based molecular dynamics simulation of the interaction between plasma ROS and the receptor-binding domain of the spike protein in the capsid protein of SARS-CoV-2

2021 ◽  
Author(s):  
Huichao Wang ◽  
Tong Zhao ◽  
Shuhui Yang ◽  
Liang Zou ◽  
Xiaolong Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Capsid Protein ◽  
Receptor Binding ◽  
Hydrogen Abstraction ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Amino Acid Residues ◽  
Global Epidemic

Abstract Under the severe situation of the current global epidemic, researchers have been working hard to find a reliable way to suppress the infection of the virus and prevent the spread of the epidemic. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 (ACE2) by the receptor-binding domain (BRD) of spike protein on the surface of SARS-CoV-2 is a crucial step for SARS-CoV-2 to invade human receptor cells, and blocking this process can inhibit the virus from invading human normal cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks the recognition and binding between the two is not clear. In this study, reaction process between reactive oxygen species (ROS) in plasma and the molecular model of RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of RBD molecule by ROS was triggered by hydrogen abstraction reactions. O and OH abstracted H atoms from RBD, while the H atoms of H2O2 and HO2 were abstracted by RBD. The hydrogen abstraction resulted in the breakage of C-H, N-H, O-H and C=O bonds and the formation of C=C, C=N bonds. The addition reaction of OH increased the number of O-H bonds and caused the formation of C-O, N-O and O-H bonds. The dissociation of N-H bonds led to the destruction of the original structure of peptide bonds and amino acid residues, change the type of amino acid residues, and caused the conversion of N-C and N=C, C=O and C-O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global epidemic problem.

scholarly journals Sensing of red blood cells with decreased membrane deformability by the human spleen

2018 ◽  
Vol 2 (20) ◽  
pp. 2581-2587 ◽  
Author(s):  
Innocent Safeukui ◽  
Pierre A. Buffet ◽  
Guillaume Deplaine ◽  
Sylvie Perrot ◽  
Valentine Brousse ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Ex Vivo ◽  
Volume Ratio ◽  
Red Cells ◽  
Human Spleen ◽  
Rbc Membrane ◽  
Membrane Rigidity ◽  
Cellular Deformability ◽  
Distinct Features

Abstract The current paradigm in the pathogenesis of several hemolytic red blood cell disorders is that reduced cellular deformability is a key determinant of splenic sequestration of affected red cells. Three distinct features regulate cellular deformability: membrane deformability, surface area-to-volume ratio (cell sphericity), and cytoplasmic viscosity. By perfusing normal human spleens ex vivo, we had previously showed that red cells with increased sphericity are rapidly sequestered by the spleen. Here, we assessed the retention kinetics of red cells with decreased membrane deformability but without marked shape changes. A controlled decrease in membrane deformability (increased membrane rigidity) was induced by treating normal red cells with increasing concentrations of diamide. Following perfusion, diamide-treated red blood cells (RBCs) were rapidly retained in the spleen with a mean clearance half-time of 5.9 minutes (range, 4.0-13.0). Splenic clearance correlated positively with increased membrane rigidity (r = 0.93; P < .0001). To determine to what extent this increased retention was related to mechanical blockade in the spleen, diamide-treated red cells were filtered through microsphere layers that mimic the mechanical sensing of red cells by the spleen. Diamide-treated red cells were retained in the microsphilters (median, 7.5%; range, 0%-38.6%), although to a lesser extent compared with the spleen (median, 44.1%; range, 7.3%-64.0%; P < .0001). Taken together, these results have implications for understanding the sensitivity of the human spleen to sequester red cells with altered cellular deformability due to various cellular alterations and for explaining clinical heterogeneity of RBC membrane disorders.

scholarly journals CELLS INVOLVED IN THE IMMUNE RESPONSE

1969 ◽  
Vol 129 (4) ◽  
pp. 757-774 ◽  
Author(s):  
Nabih I. Abdou ◽  
Maxwell Richter
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Bone Marrow Cells ◽  
Allogeneic Bone Marrow ◽  
Red Cells ◽  
Allogeneic Bone ◽  
Sheep Red Blood Cells ◽  
Sheep Red Cells

Irradiated rabbits given allogeneic bone marrow cells from normal adult donors responded to an injection of sheep red blood cells by forming circulating antibodies. Their spleen cells were also capable of forming many plaques using the hemolysis in gel technique, and were also capable of undergoing blastogenesis and mitosis and of incorporating tritiated thymidine upon exposure to the specific antigen in vitro. However, irradiated rabbits injected with allogeneic bone marrow obtained from rabbits injected with sheep red blood cells 24 hr prior to sacrifice (primed donors) were incapable of mounting an immune response after stimulation with sheep red cells. This loss of reactivity by the bone marrow from primed donors is specific for the antigen injected, since the immune response of the irradiated recipients to a non-cross-reacting antigen, the horse red blood cell, is unimpaired. Treatment of the bone marrow donors with high-titered specific antiserum to sheep red cells for 24 hr prior to sacrifice did not result in any diminished ability of their bone marrow cells to transfer antibody-forming capacity to sheep red blood cells. The significance of these results, with respect to the origin of the antigen-reactive and antibody-forming cells in the rabbit, is discussed.

scholarly journals Antagonists of the system L neutral amino acid transporter (LAT) promote endothelial adhesivity of human red blood cells

2017 ◽  
Vol 117 (07) ◽  
pp. 1402-1411 ◽  
Author(s):  
Laura Beth Mann Dosier ◽  
Vikram J. Premkumar ◽  
Hongmei Zhu ◽  
Izzet Akosman ◽  
Michael F. Wempe ◽  
...  
Keyword(s):  
Amino Acid ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Amino Acid Transporter ◽  
Neutral Amino Acid ◽  
Neutral Amino Acid Transporter ◽  
System L

SummaryThe system L neutral amino acid transporter (LAT; LAT1, LAT2, LAT3, or LAT4) has multiple functions in human biology, including the cellular import of S-nitrosothiols (SNOs), biologically active derivatives of nitric oxide (NO). SNO formation by haemoglobin within red blood cells (RBC) has been studied, but the conduit whereby a SNO leaves the RBC remains unidentified. Here we hypothesised that SNO export by RBCs may also depend on LAT activity, and investigated the role of RBC LAT in modulating SNO-sensitive RBC-endothelial cell (EC) adhesion. We used multiple pharmacologic inhibitors of LAT in vitro and in vivo to test the role of LAT in SNO export from RBCs and in thereby modulating RBC-EC adhesion. Inhibition of human RBC LAT by type-1-specific or nonspecific LAT antagonists increased RBC-endothelial adhesivity in vitro, and LAT inhibitors tended to increase post-transfusion RBC sequestration in the lung and decreased oxygenation in vivo. A LAT1-specific inhibitor attenuated SNO export from RBCs, and we demonstrated LAT1 in RBC membranes and LAT1 mRNA in reticulocytes. The proadhesive effects of inhibiting LAT1 could be overcome by supplemental L-CSNO (S-nitroso-L-cysteine), but not D-CSNO or L-Cys, and suggest a basal anti-adhesive role for stereospecific intercellular SNO transport. This study reveals for the first time a novel role of LAT1 in the export of SNOs from RBCs to prevent their adhesion to ECs. The findings have implications for the mechanisms of intercellular SNO signalling, and for thrombosis, sickle cell disease, and post-storage RBC transfusion, when RBC adhesivity is increased.

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