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PLoS Computational Biology Jun 2020Transmembrane helix association is a fundamental step in the folding of helical membrane proteins. The prototypical example of this association is formation of the...
Transmembrane helix association is a fundamental step in the folding of helical membrane proteins. The prototypical example of this association is formation of the glycophorin dimer. While its structure and stability have been well-characterized experimentally, the detailed assembly mechanism is harder to obtain. Here, we use all-atom simulations within phospholipid membrane to study glycophorin association. We find that initial association results in the formation of a non-native intermediate, separated by a significant free energy barrier from the dimer with a native binding interface. We have used transition-path sampling to determine the association mechanism. We find that the mechanism of the initial bimolecular association to form the intermediate state can be mediated by many possible contacts, but seems to be particularly favoured by formation of non-native contacts between the C-termini of the two helices. On the other hand, the contacts which are key to determining progression from the intermediate to the native state are those which define the native binding interface, reminiscent of the role played by native contacts in determining folding of globular proteins. As a check on the simulations, we have computed association and dissociation rates from the transition-path sampling. We obtain results in reasonable accord with available experimental data, after correcting for differences in native state stability. Our results yield an atomistic description of the mechanism for a simple prototype of helical membrane protein folding.
Topics: Dimerization; Glycophorins; Membrane Proteins; Molecular Dynamics Simulation; Protein Binding; Protein Folding; Protein Structure, Secondary
PubMed: 32497094
DOI: 10.1371/journal.pcbi.1007919 -
Current Opinion in Structural Biology Aug 1997Recently, methods for the analysis and design of water-soluble, oligomeric bundles of alpha helices, including coiled coils, have reached a high level of sophistication.... (Review)
Review
Recently, methods for the analysis and design of water-soluble, oligomeric bundles of alpha helices, including coiled coils, have reached a high level of sophistication. These same methods may now be applied to transmembrane helical bundles. Studies of the transmembrane domains of glycophorin, phospholamban, and the M2 protein from influenza A virus exemplify this general approach.
Topics: Calcium-Binding Proteins; Computer Simulation; Glycophorins; Influenza A virus; Membrane Proteins; Models, Molecular; Protein Conformation; Viral Matrix Proteins
PubMed: 9266169
DOI: 10.1016/s0959-440x(97)80111-x -
The Journal of Biological Chemistry Jan 1993Human glycophorin A, B, and E genes are homologous from the 5'-flanking region to 1 kilobase downstream from the exon encoding the transmembrane region. Analysis of... (Comparative Study)
Comparative Study
Human glycophorin A, B, and E genes are homologous from the 5'-flanking region to 1 kilobase downstream from the exon encoding the transmembrane region. Analysis of human Alu sequences at the transition site from the homologous to nonhomologous region suggested that the GPA gene most closely resembles the ancestral gene, whereas GPB and GPE genes arose by homologous recombination within the Alu repetitive sequence, and acquired 3' sequences from an unrelated gene (Kudo, S., and Fukuda, M. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 4619-4623; Kudo, S., and Fukuda, M. (1990) J. Biol. Chem. 265, 1102-1110). To understand glycophorin gene evolution in primate phylogeny, transmembrane and Alu regions of several primate genomes were amplified by the polymerase chain reaction and their sequences were analyzed. These studies revealed that the GPA gene was present in all primates studied, and the GPB gene was present in pygmy chimpanzee, chimpanzee, and gorilla, but absent from orangutan and gibbon. GPE gene was present in all species with a GPB gene, but was detected in only 7 out of 16 gorillas. The 24-base pair insertion sequence found in the transmembrane exon of the human GPE gene was shown to be derived from the ancestral GPB gene and was inserted into the ancestral GPE gene prior to gorilla divergence. The recombination site in the GPA gene was confirmed to be within an Alu repetitive sequence. We conclude that GPB and GPE genes arose from an ancestral GPA gene via two gene duplications occurring during primate evolution, prior to gorilla divergence.
Topics: Amino Acid Sequence; Animals; Base Sequence; Biological Evolution; Exons; Glycophorins; Gorilla gorilla; Humans; Molecular Sequence Data; Multigene Family; Pan troglodytes; Polymerase Chain Reaction; Primates; Repetitive Sequences, Nucleic Acid; Sequence Homology, Nucleic Acid; Sialoglycoproteins
PubMed: 8420995
DOI: No ID Found -
Blood Oct 1992
Review
Topics: Chromosomes, Human, Pair 4; Erythrocyte Membrane; Glycophorins; Humans; Molecular Structure; Mutation
PubMed: 1391951
DOI: No ID Found -
Journal of Cellular and Molecular... Aug 2021Anaemia is one of the leading causes of disability in young adults and is associated with increased morbidity and mortality in elderly. With a global target to reduce...
Anaemia is one of the leading causes of disability in young adults and is associated with increased morbidity and mortality in elderly. With a global target to reduce the disease burden of anaemia, recent researches focus on novel compounds with the ability to induce erythropoiesis and regulate iron homeostasis. We aimed to explore the biological events and potential polypharmacological effects of water-extracted olive leaf (WOL) on human bone marrow-derived haematopoietic stem cells (hHSCs) using a comprehensive gene expression analysis. HPLC analysis identifies six bioactive polyphenols in the WOL. Treatment with WOL for 12 days regulated gene expressions related to erythroid differentiation, oxygen homeostasis, iron homeostasis, haem metabolism and Hb biosynthesis in hHSCs. Functional clustering analysis reveals several major functions of WOL such as ribosomal biogenesis and mitochondrial translation machinery, glycolytic process, ATP biosynthesis and immune response. Additionally, the colonies of both primitive and mature erythroid progenitors, CFU-E and BFU-E, were significantly increased in WOL-treated hHSCs. The expressions of erythroid markers, CD47, glycophorin A (GYPA), and transferrin receptor (TFRC) and adult Hb subunits-HBA and HBB were also confirmed in immunofluorescent staining and flow cytometer analysis in WOL-treated hHSCs. It is well known that induction of lineage-specific differentiation, as well as the maturation of early haematopoietic precursors into fully mature erythrocytes, involves multiple simultaneous biological events and complex signalling networks. In this regard, our genome-wide transcriptome profiling with microarray study on WOL-treated hHSCs provides general insights into the multitarget prophylactic and/or therapeutic potential of WOL in anaemia and other haematological disorders.
Topics: CD47 Antigen; Cells, Cultured; Erythropoiesis; Glycophorins; Hematopoietic Stem Cells; Hemoglobins; Humans; K562 Cells; Olea; Plant Extracts; Plant Leaves; Receptors, Transferrin; Transcriptome
PubMed: 34180123
DOI: 10.1111/jcmm.16752 -
European Journal of Biochemistry Nov 1988Glycophorins A and B are homologous glycoproteins of the red cell membrane which carry the blood-group MN and Ss antigens, respectively, and are encoded by two distinct...
Glycophorins A and B are homologous glycoproteins of the red cell membrane which carry the blood-group MN and Ss antigens, respectively, and are encoded by two distinct genes closely linked on chromosome 4, which are probably derived from each other by duplication during evolution. The lack of glycophorin A is associated with the rare phenotype En(a-), indicating individuals who are defective for MN antigens, as well as for the Ena antigens, also located on this glycoprotein. The En(a-) condition is heterogenous and includes two categories of variants exemplified by the Finnish and the English types referred to as En(Fin) and En(UK), respectively. By Southern blot and preliminary genomic clone analyzes we have compared the status of the genes for glycophorins A and B, as well as that of the gene encoding glycophorin C, another unrelated red cell membrane glycoprotein, in the En(a-) variants and in the En(a+) control donors. Our data indicate that the En(Fin) variant is homozygous for a complete deletion of the glycophorin A gene without any detectable abnormality of the genes encoding glycophorins B or C. In the genome of the En(UK) variant, with the presumed genotype Mk/En(UK), and where the Mk condition abolishes the expression of MN and Ss antigens, we have identified several abnormalities of the glycophorin A and B genes, but the glycophorin C gene was unaffected. Our results strongly support the view that in Mk chromosome the glycophorin A and B genes are largely deleted, whereas the En(UK) chromosome probably contains a gene fusion product encoding a hybrid glycoprotein AM-B, composed of the N-terminal portion of a blood group M-type glycophorin A and of the C-terminal portion of glycophorin B. The determination of the 5' and 3' limits of the hybrid gene and elucidation of the mechanism involved will require sequencing of the rearranged DNA of the variant and a full knowledge of the organization of the glycophorin A and B genes.
Topics: Blotting, Southern; Chromosomes, Human, Pair 4; DNA; DNA Probes; Genes; Glycophorins; Humans; Multigene Family; Nucleic Acid Hybridization; Sialoglycoproteins
PubMed: 3197721
DOI: 10.1111/j.1432-1033.1988.tb14413.x -
Science (New York, N.Y.) Dec 2013Erythropoietin is a signaling glycoprotein that controls the fundamental process of erythropoiesis, orchestrating the production and maintenance of red blood cells. As...
Erythropoietin is a signaling glycoprotein that controls the fundamental process of erythropoiesis, orchestrating the production and maintenance of red blood cells. As administrated clinically, erythropoietin has a polypeptide backbone with complex dishomogeneity in its carbohydrate domains. Here we describe the total synthesis of homogeneous erythropoietin with consensus carbohydrate domains incorporated at all of the native glycosylation sites. The oligosaccharide sectors were built by total synthesis and attached stereospecifically to peptidyl fragments of the wild-type primary sequence, themselves obtained by solid-phase peptide synthesis. The glycopeptidyl constructs were joined by chemical ligation, followed by metal-free dethiylation, and subsequently folded. This homogeneous erythropoietin glycosylated at the three wild-type aspartates with N-linked high-mannose sialic acid-containing oligosaccharides and O-linked glycophorin exhibits Procrit-level in vivo activity in mice.
Topics: Amino Acid Sequence; Animals; Aspartic Acid; Cells, Cultured; Consensus Sequence; Dose-Response Relationship, Drug; Erythrocyte Count; Erythropoietin; Glycophorins; Glycosylation; Injections, Subcutaneous; Mannose; Mice; Mice, Inbred C57BL; Molecular Sequence Data; N-Acetylneuraminic Acid; Oligosaccharides; Reticulocytes
PubMed: 24337294
DOI: 10.1126/science.1245095 -
European Journal of Biochemistry Feb 1981The human erythroid cell line, K562, synthesizes the major red cell sialoglycoprotein, glycophorin A. We have isolated an mRNA fraction which codes for glycophorin A...
The human erythroid cell line, K562, synthesizes the major red cell sialoglycoprotein, glycophorin A. We have isolated an mRNA fraction which codes for glycophorin A from K562 cells and studied the synthesis of the sialoglycoprotein in a rabbit reticulocyte cell-free system. In the absence of membranes a precursor form of glycophorin A was synthesized. This was identified using specific anti-(glycophorin A) serum. The apparent molecular weight of the carbohydrate-free precursor of glycophorin A was 19 500. This exceeds the molecular weight of the glycophorin A apoprotein by approximately 5000. In the presence of membranes from dog pancreas, the synthesized glycophorin A precursor was N-glycosylated and probably also O-glycosylated. The oligosaccharide chains remained incomplete and the glycoprotein synthesized in vitro corresponded to the glycosylated precursor of glycophorin A obtained in intact cells.
Topics: Animals; Cell Line; Cell-Free System; Erythrocytes; Glycophorins; Humans; Protein Biosynthesis; RNA, Messenger; Rabbits; Reticulocytes; Sialoglycoproteins
PubMed: 7215358
DOI: 10.1111/j.1432-1033.1981.tb05159.x -
Biochimica Et Biophysica Acta Nov 2016Several lines of evidence suggest that glycophorin A (GPA) interacts with band 3 in human erythrocyte membranes including: i) the existence of an epitope shared between...
Several lines of evidence suggest that glycophorin A (GPA) interacts with band 3 in human erythrocyte membranes including: i) the existence of an epitope shared between band 3 and GPA in the Wright b blood group antigen, ii) the fact that antibodies to GPA inhibit the diffusion of band 3, iii) the observation that expression of GPA facilitates trafficking of band 3 from the endoplasmic reticulum to the plasma membrane, and iv) the observation that GPA is diminished in band 3 null erythrocytes. Surprisingly, there is also evidence that GPA does not interact with band 3, including data showing that: i) band 3 diffusion increases upon erythrocyte deoxygenation whereas GPA diffusion does not, ii) band 3 diffusion is greatly restricted in erythrocytes containing the Southeast Asian Ovalocytosis mutation whereas GPA diffusion is not, and iii) most anti-GPA or anti-band 3 antibodies do not co-immunoprecipitate both proteins. To try to resolve these apparently conflicting observations, we have selectively labeled band 3 and GPA with fluorescent quantum dots in intact erythrocytes and followed their diffusion by single particle tracking. We report here that band 3 and GPA display somewhat similar macroscopic and microscopic diffusion coefficients in unmodified cells, however perturbations of band 3 diffusion do not cause perturbations of GPA diffusion. Taken together the collective data to date suggest that while weak interactions between GPA and band 3 undoubtedly exist, GPA and band 3 must have separate interactions in the membrane that control their lateral mobility.
Topics: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; Animals; Anion Exchange Protein 1, Erythrocyte; Biotin; Biotinylation; Camelus; Erythrocyte Membrane; Fluorescence; Gene Expression; Glycophorins; Humans; Molecular Imaging; Molecular Probes; Protein Transport; Quantum Dots; Recombinant Proteins; Single-Domain Antibodies
PubMed: 27580023
DOI: 10.1016/j.bbamem.2016.08.012 -
Blood Advances Jan 2018Lutheran/basal cell adhesion molecule (Lu/BCAM) is a transmembrane adhesion molecule expressed by erythrocytes and endothelial cells that can interact with the...
Lutheran/basal cell adhesion molecule (Lu/BCAM) is a transmembrane adhesion molecule expressed by erythrocytes and endothelial cells that can interact with the extracellular matrix protein laminin-α5. In sickle cell disease, Lu/BCAM is thought to contribute to adhesion of sickle erythrocytes to the vascular wall, especially during vaso-occlusive crises. On healthy erythrocytes however, its function is unclear. Here we report that Lu/BCAM is activated during erythrocyte aging. We show that Lu/BCAM-mediated binding to laminin-α5 is restricted by interacting, in cis, with glycophorin-C-derived sialic acid residues. Following loss of sialic acid during erythrocyte aging, Lu/BCAM is released from glycophorin-C and allowed to interact with sialic acid residues on laminin-α5. Decreased glycophorin-C sialylation, as observed in individuals lacking exon 3 of glycophorin-C, the so-called Gerbich phenotype, was found to correlate with increased Lu/BCAM-dependent binding to laminin-α5. In addition, we identified the sialic acid-binding site within the third immunoglobulin-like domain within Lu/BCAM that accounts for the interaction with glycophorin-C and laminin-α5. Last, we present evidence that neuraminidase-expressing pathogens, such as , can similarly induce Lu/BCAM-mediated binding to laminin-α5, by cleaving terminal sialic acid residues from the erythrocyte membrane. These results shed new light on the mechanisms contributing to increased adhesiveness of erythrocytes at the end of their lifespan, possibly facilitating their clearance. Furthermore, this work may contribute to understanding the pathology induced by neuraminidase-positive bacteria, because they are especially harmful to patients suffering from sickle cell disease and are associated with the occurrence of vaso-occlusive crises.
Topics: Anemia, Sickle Cell; Binding Sites; Cell Adhesion; Cell Adhesion Molecules; Erythrocyte Aging; Glycophorins; Humans; Laminin; Lutheran Blood-Group System; N-Acetylneuraminic Acid; Neuraminidase
PubMed: 29344581
DOI: 10.1182/bloodadvances.2017013094