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Trueba-Gómez R, Rosenfeld-Mann F, Estrada-Juárez H. Prediction of the antigenic regions in eight RhD variants identified by computational biology. Vox Sang 2024; 119:590-597. [PMID: 38523363 DOI: 10.1111/vox.13620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/23/2024] [Accepted: 03/08/2024] [Indexed: 03/26/2024]
Abstract
BACKGROUND AND OBJECTIVES Changes in RHD generate variations in protein structure that lead to antigenic variants. The classical model divides them into quantitative (weak and Del) and qualitative (partial D). There are two types of protein antigens: linear and conformational. Computational biology analyses the theoretical assembly of tertiary protein structures and allows us to identify the 'topological' differences between isoforms. Our aim was to determine the theoretical antigenic differences between weak RhD variants compared with normal RhD based on structural analysis using bioinformatic techniques. MATERIALS AND METHODS We analysed the variations in secondary structures and hydrophobicity of RHD*01, RHD*01W.1, W2, W3, RHD*09.03.01, RHD*09.04, RHD*11, RHD*15 and RHD*21. We then modelled the tertiary structure and calculated their probable antigenic regions, intra-protein interactions, displacement and membrane width and compared them with Rhce. RESULTS The 10 proteins are similar in their secondary structure and hydrophobicity, with the main differences observed in the exofacial coils. We identified six potential antigenic regions: one that is unique to RhD (R3), one that is common to all D (R6), three that are highly variable among RhD isoforms (R1, R2 and R4), one that they share with Rhce (R5) and two that are unique to Rhce (Ra and Rbc). CONCLUSION The alloimmunization capacity of these subjects could be explained by the variability of the antigen pattern, which is not necessarily recognized or recognized with lower intensity by the commercially available antibodies, and not because they have a lower protein concentration in the membrane.
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Affiliation(s)
- Rocio Trueba-Gómez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes," Coordinación de Hematología Perinatal, Mexico City, Mexico
- Comité de Trombosis y Hemostasia AMEH-CLAHT, A.C., Mexico City, Mexico
| | | | - Higinio Estrada-Juárez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes," Coordinación de Hematología Perinatal, Mexico City, Mexico
- Comité de Trombosis y Hemostasia AMEH-CLAHT, A.C., Mexico City, Mexico
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Floch A, Galochkina T, Pirenne F, Tournamille C, de Brevern AG. Molecular dynamics of the human RhD and RhAG blood group proteins. Front Chem 2024; 12:1360392. [PMID: 38566898 PMCID: PMC10985258 DOI: 10.3389/fchem.2024.1360392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction: Blood group antigens of the RH system (formerly known as "Rhesus") play an important role in transfusion medicine because of the severe haemolytic consequences of antibodies to these antigens. No crystal structure is available for RhD proteins with its partner RhAG, and the precise stoichiometry of the trimer complex remains unknown. Methods: To analyse their structural properties, the trimers formed by RhD and/or RhAG subunits were generated by protein modelling and molecular dynamics simulations were performed. Results: No major differences in structural behaviour were found between trimers of different compositions. The conformation of the subunits is relatively constant during molecular dynamics simulations, except for three large disordered loops. Discussion: This work makes it possible to propose a reasonable stoichiometry and demonstrates the potential of studying the structural behaviour of these proteins to investigate the hundreds of genetic variants relevant to transfusion medicine.
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Affiliation(s)
- Aline Floch
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Tatiana Galochkina
- Université Paris Cité and Université des Antilles and Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, DSIMB Bioinformatics team, Paris, France
| | - France Pirenne
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Christophe Tournamille
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Alexandre G. de Brevern
- Université Paris Cité and Université des Antilles and Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, DSIMB Bioinformatics team, Paris, France
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Trueba-Gómez R, Rosenfeld-Mann F, Baptista-González HA, Domínguez-López ML, Estrada-Juárez H. Use of computational biology to compare the theoretical tertiary structures of the most common forms of RhCE and RhD. Vox Sang 2023; 118:881-890. [PMID: 37559188 DOI: 10.1111/vox.13509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 07/11/2023] [Accepted: 07/21/2023] [Indexed: 08/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Computational biology analyses the theoretical tertiary structure of proteins and identifies the 'topological' differences between RhD and RhCE. Our aim was to identify the theoretical structural differences between the four isoforms of RhCE and RhD using computational biological tools. MATERIALS AND METHODS Physicochemical profile was determined by hydrophobicity and electrostatic potential analysis. Secondary and tertiary structures were generated using computational biology tools. The structures were evaluated and validated using Ramachandran algorithm, which calculates the single score, p-value and root mean square deviation (RMSD). Structures were overlaid on local refinement of 'RhAG-RhCE-ANK' (PBDID 7uzq) and RhAG to compare their spatial distribution within the membrane. RESULTS All proteins differed in surface area and electrostatic distance due to variations in hydrophobicity and electrostatic potential. The RMSD between RhD and RhCE was 0.46 ± 0.04 Å, and the comparison within RhCE was 0.57 ± 0.08 Å. The percentage of amino acids in the hydrophobic thickness was 50.24% for RhD while for RhCE it ranged between 73.08% and 76.68%. The RHAG hydrophobic thickness was 34.2 Å, and RhCE's hydrophobic thickness was 33.83 Å. We suggest that the C/c antigens differ exofacially at loops L1 and L2. For the E/e antigens, the difference lies in L6. By contrast, L4 is the same for all proteins except Rhce. CONCLUSION The physicochemical properties of Rh proteins made them different, although their genes are homologous. Using computational biology, we model structures with sufficient precision, similar to those obtained experimentally. An amino acid variation alters the folding of the tertiary structure and the interactions with other proteins, modifying the electrostatic environment, the spatial conformations and therefore the antigenic recognition.
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Affiliation(s)
- Rocio Trueba-Gómez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
- Posgrado en Ciencias Químico Biológicas, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Fany Rosenfeld-Mann
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
| | - Hector A Baptista-González
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
| | - María L Domínguez-López
- Posgrado en Ciencias Químico Biológicas, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Higinio Estrada-Juárez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
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Flegel WA. Proceed with care: the "uncommon" serologic weak D phenotypes. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2021; 19:272-276. [PMID: 34704554 PMCID: PMC8297679 DOI: 10.2450/2021.0147-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
- Huazhong University of Science and Technology, Wuhan, Hubei, China
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Raud L, Le Tertre M, Vigneron L, Ka C, Richard G, Callebaut I, Chen JM, Férec C, Le Gac G, Fichou Y. Missense RHD single nucleotide variants induce weakened D antigen expression by altering splicing and/or protein expression. Transfusion 2021; 61:2468-2476. [PMID: 34110623 DOI: 10.1111/trf.16538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/09/2021] [Accepted: 04/28/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Although D variant phenotype is known to be due to genetic defects, including rare missense single nucleotide variants (SNVs), within the RHD gene, few studies have addressed the molecular and cellular mechanisms driving this altered expression. We and others showed previously that splicing is commonly disrupted by SNVs in constitutive splice sites and their vicinity. We thus sought to investigate whether rare missense SNVs located in "deep" exonic regions could also impair this mechanism. STUDY DESIGN AND METHODS Forty-six missense SNVs reported within exons 6 and 7 were first selected from the Human RhesusBase. Their respective effect on splicing was assessed by using an in vitro assay. An RhD-negative cell model was further generated by using the CRISPR-Cas9 approach. RhD-mutated proteins were overexpressed in the newly created model, and cell membrane expression of the D antigen was measured by flow cytometry. RESULTS Minigene splicing assay showed that 14 of 46 (30.4%) missense SNVs alter splicing. Very interestingly, further investigation of two missense SNVs, which both affect codon 338 and confer a weak D phenotype, showed various mechanisms: c.1012C>G (p.Leu338Val) disrupts splicing only, while c.1013T>C (p.Leu338Pro) alters only the protein structure, in agreement with in silico prediction tools and 3D protein structure visualization. CONCLUSION Our functional data set suggests that missense SNVs damage quantitatively D antigen expression by, at least, two different mechanisms (splicing alteration and protein destabilization) that may act independently. These data thereby contribute to extend the current knowledge of the molecular mechanisms governing weakened D expression.
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Affiliation(s)
- Loann Raud
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Marlène Le Tertre
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | | | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Gaëlle Richard
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Gérald Le Gac
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
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Floch A, Pirenne F, Barrault A, Chami B, Toly-Ndour C, Tournamille C, de Brevern AG. Insights into anti-D formation in carriers of RhD variants through studies of 3D intraprotein interactions. Transfusion 2021; 61:1286-1301. [PMID: 33586199 DOI: 10.1111/trf.16301] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/04/2020] [Accepted: 01/13/2021] [Indexed: 01/11/2023]
Abstract
BACKGROUND Many RhD variants associated with anti-D formation (partial D) in carriers exposed to the conventional D antigen carry mutations affecting extracellular loop residues. Surprisingly, some carry mutations affecting transmembrane or intracellular domains, positions not thought likely to have a major impact on D epitopes. STUDY DESIGN AND METHODS A wild-type Rh trimer (RhD1 RhAG2 ) was modeled by comparative modeling with the human RhCG structure. Taking trimer conformation, residue accessibility, and position relative to the lipid bilayer into account, we redefine the domains of the RhD protein. We generated models for RhD variants carrying one or two amino acid substitutions associated with anti-D formation in published articles (25 variants) or abstracts (12 variants) and for RHD*weak D type 38. We determined the extracellular substitutions and compared the interactions of the variants with those of the standard RhD. RESULTS The findings of the three-dimensional (3D) analysis were correlated with anti-D formation for 76% of RhD variants: 15 substitutions associated with anti-D formation concerned extracellular residues, and structural differences in intraprotein interactions relative to standard RhD were observed in the others. We discuss the mechanisms by which D epitopes may be modified in variants in which the extracellular residues are identical to those of standard RhD and provide arguments for the benignity of p.T379M (RHD*DAU0) and p.G278D (RHD*weak D type 38) in transfusion medicine. CONCLUSION The study of RhD intraprotein interactions and the precise redefinition of residue accessibility provide insight into the mechanisms through which RhD point mutations may lead to anti-D formation in carriers.
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Affiliation(s)
- Aline Floch
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - France Pirenne
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Aurélie Barrault
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Btissam Chami
- Etablissement francais du sang Ile-de-France, Creteil, France
| | - Cécile Toly-Ndour
- Unité Fonctionnelle d'expertise en Immuno-Hémobiologie Périnatale, Centre National de Référence en Hémobiologie Périnatale (CNRHP), Service de Médecine Fœtale, Pôle Périnatalité, Hôpital Trousseau, GH HUEP, APHP, Paris, France
| | - Christophe Tournamille
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Alexandre G de Brevern
- Laboratoire d'Excellence GR-Ex, Paris, France.,Université de Paris, Biologie Intégrée du Globule Rouge UMR_S1134, Inserm, Université de la Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine (INTS), Paris, France
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