1
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Siar EH, Abellanas-Perez P, Rocha-Martin J, Fernandez-Lafuente R. Tailoring the specificity of ficin versus large hemoglobin and small casein by co-immobilizing inert proteins on the immobilized enzyme layer and further modification with aldehyde dextran. Int J Biol Macromol 2024; 277:134487. [PMID: 39102910 DOI: 10.1016/j.ijbiomac.2024.134487] [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: 05/30/2024] [Revised: 07/31/2024] [Accepted: 08/02/2024] [Indexed: 08/07/2024]
Abstract
Ficin has been immobilized at full loading on glyoxyl agarose beads. Then, ficin was blocked with 2,2'-dipyridyldisulfide. To be effective, the modification must be performed in the presence of 0.5 M urea, as the enzyme was not inhibited under standard conditions, very likely because the catalytic Cys was not fully exposed to the medium. Activity could be fully recovered by incubation with 1 M mercaptoethanol. This biocatalyst could hydrolyze hemoglobin and casein. The objective of this paper was to increase the enzyme specificity versus small proteins by generating steric hindrances to the access of large proteins. The step by step blocking via ionic exchange of the biocatalyst with aminated bovine serum albumin (BSA), aldehyde dextran and a second layer of aminated BSA produced a biocatalyst that maintained its activity versus small synthetic substrates, increased the biocatalyst stability, while reduced its activity to over 50 % versus casein. Interestingly, this treatment almost fully annulled the activity versus hemoglobin, more effectively at 37 °C than at 55 °C. The biocatalyst could be reused 5 times without changes in activity. The changes could be caused by steric hindrances, but it cannot be discarded some changes in enzyme sequence specificity caused by the modifications.
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Affiliation(s)
- El Hocine Siar
- Departamento de Biocatálisis, ICP-CSIC, Campus UAM-CSIC, 28049 Madrid, Spain; Transformation and Food Product Elaboration Laboratory, Nutrition and Food Technology Institute (INATAA), University of Brothers Mentouri Constantine 1, Constantine, Algeria
| | | | - Javier Rocha-Martin
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Complutense University of Madrid, José Antonio Novais 12, Madrid 28040, Spain.
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2
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Biochemical and Bioinformatic Studies of Mutations of Residues at the Monomer-Monomer Interface of Human Ornithine Aminotransferase Leading to Gyrate Atrophy of Choroid and Retina. Int J Mol Sci 2023; 24:ijms24043369. [PMID: 36834788 PMCID: PMC9967328 DOI: 10.3390/ijms24043369] [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: 12/22/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Deficit of human ornithine aminotransferase (hOAT), a mitochondrial tetrameric pyridoxal-5'-phosphate (PLP) enzyme, leads to gyrate atrophy of the choroid and retina (GA). Although 70 pathogenic mutations have been identified, only few enzymatic phenotypes are known. Here, we report biochemical and bioinformatic analyses of the G51D, G121D, R154L, Y158S, T181M, and P199Q pathogenic variants involving residues located at the monomer-monomer interface. All mutations cause a shift toward a dimeric structure, and changes in tertiary structure, thermal stability, and PLP microenvironment. The impact on these features is less pronounced for the mutations of Gly51 and Gly121 mapping to the N-terminal segment of the enzyme than those of Arg154, Tyr158, Thr181, and Pro199 belonging to the large domain. These data, together with the predicted ΔΔG values of monomer-monomer binding for the variants, suggest that the proper monomer-monomer interactions seem to be correlated with the thermal stability, the PLP binding site and the tetrameric structure of hOAT. The different impact of these mutations on the catalytic activity was also reported and discussed on the basis of the computational information. Together, these results allow the identification of the molecular defects of these variants, thus extending the knowledge of enzymatic phenotypes of GA patients.
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3
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Hale OJ, Cooper HJ. Native Mass Spectrometry Imaging and In Situ Top-Down Identification of Intact Proteins Directly from Tissue. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2531-2537. [PMID: 32822168 DOI: 10.1021/jasms.0c00226] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mass spectrometry imaging (MSI) provides information on the spatial distribution of molecules within a biological substrate without the requirement for labeling. Its broad specificity, i.e., the capability to spatially profile any analyte ion detected, constitutes a major advantage over other imaging techniques. A separate branch of mass spectrometry, native mass spectrometry, provides information relating to protein structure through retention of solution-phase interactions in the gas phase. Integration of MSI and native mass spectrometry ("native MSI") affords opportunities for simultaneous acquisition of spatial and structural information on proteins directly from their physiological environment. Here, we demonstrate significant improvements in native MSI and associated protein identification of intact proteins and protein assemblies in thin sections of rat kidney by use of liquid extraction surface analysis on a state-of-the-art Orbitrap mass spectrometer optimized for intact protein analysis. Proteins of up to 47 kDa, including a trimeric protein complex, were imaged and identified.
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Affiliation(s)
- Oliver J Hale
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, U.K
| | - Helen J Cooper
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, U.K
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4
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Astegno A, Conter C, Bertoldi M, Dominici P. Structural Insights into the Heme Pocket and Oligomeric State of Non-Symbiotic Hemoglobins from Arabidopsis thaliana. Biomolecules 2020; 10:E1615. [PMID: 33260415 PMCID: PMC7761212 DOI: 10.3390/biom10121615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 11/18/2022] Open
Abstract
Non-symbiotic hemoglobins AHb1 and AHb2 from Arabidopsis thaliana are hexacoordinate heme-proteins that likely have different biological roles, in view of diverse tissue localization, expression pattern, and ligand binding properties. Herein, we expand upon previous biophysical studies on these isoforms, focusing on their oligomeric states and circular dichroism (CD) characteristics. We found that AHb1 exists in solution in a concentration-dependent monomer-dimer equilibrium, while AHb2 is present only as a monomer. The quaternary structure of AHb1 affects its degree of hexacoordination with the formation of the dimer that enhances pentacoordination. Accordingly, the mutant of a conserved residue within the dimeric interface, AHb1-T45A, which is mostly monomeric in solution, has an equilibrium that is shifted toward a hexacoordinate form compared to the wild-type protein. CD studies further support differences in the globin's structure and heme moiety. The Soret CD spectra for AHb2 are opposite in sense to those for AHb1, reflecting different patterns of heme-protein side chain contacts in the two proteins. Moreover, the smaller contribution of the heme to the near-UV CD in AHb2 compared to AHb1 suggests a weaker heme-protein association in AHb2. Our data corroborate the structural diversity of AHb1 and AHb2 and confirm the leghemoglobin-like structural properties of AHb2.
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Affiliation(s)
- Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy; (A.A.); (C.C.)
| | - Carolina Conter
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy; (A.A.); (C.C.)
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie, 8, 37134 Verona, Italy;
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy; (A.A.); (C.C.)
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5
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Manning LR, Manning JM. Nano gel filtration reveals how fish hemoglobins release oxygen: The Root Effect. Anal Biochem 2020; 599:113730. [PMID: 32289258 DOI: 10.1016/j.ab.2020.113730] [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: 02/23/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 11/15/2022]
Abstract
The Root Effect is to many species of fish what the Bohr Effect is to humans regarding the release of O2 from their hemoglobins at low pH. However, Root Effect hemoglobins accomplish this more extensively than human adult hemoglobin in order to satisfy the diverse oxygen requirements in fish. To understand this difference between fish and human hemoglobins, we studied their subunit interface strengths using very low (nanomolar) concentrations, referred to as nano gel filtration. Root Effect hemoglobins in their CO form dissociate in a tetramer-monomer equilibrium. In contrast, tetramers and dimers but no monomers are found for adult human hemoglobin consistent with its well known tetramer-dimer equilibrium. By analogy to the human variant Hb Kansas and a similar recombinant Hb, both of which readily release oxygen due to an unstable oxygenated structure, the mechanism proposed is that oxygenated Root Effect tetramers release their oxygen to form energetically stable deoxygenated tetramers rather than dissociate to energetically unfavorable oxygenated dimers with labile interfaces. In contrast, the strong binding of CO permits observation of dissociation to monomers, thus revealing an intrinsic property of Root Effect fish hemoglobins enabling it to function as an oxygen pump.
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Affiliation(s)
- Lois R Manning
- Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - James M Manning
- Department of Biology, Northeastern University, Boston, MA, 02115, USA.
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6
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Hale OJ, Sisley EK, Griffiths RL, Styles IB, Cooper HJ. Native LESA TWIMS-MSI: Spatial, Conformational, and Mass Analysis of Proteins and Protein Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:873-879. [PMID: 32159346 PMCID: PMC7147347 DOI: 10.1021/jasms.9b00122] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/13/2020] [Accepted: 02/18/2020] [Indexed: 05/18/2023]
Abstract
We have previously demonstrated native liquid extraction surface analysis (LESA) mass spectrometry imaging of small intact proteins in thin tissue sections. We also showed calculation of collision cross sections for specific proteins extracted from discrete locations in tissue by LESA traveling wave ion mobility spectrometry (TWIMS). Here, we demonstrate an integrated native LESA TWIMS mass spectrometry imaging (MSI) workflow, in which ion mobility separation is central to the imaging experiment and which provides spatial, conformational, and mass information on endogenous proteins in a single experiment. The approach was applied to MSI of a thin tissue section of mouse kidney. The results show that the benefits of integration of TWIMS include improved specificity of the ion images and the capacity to calculate collision cross sections for any protein or protein complex detected in any pixel (without a priori knowledge of the presence of the protein).
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Affiliation(s)
- Oliver J. Hale
- School of Biosciences, University of
Birmingham, Edgbaston B15 2TT, U.K.
| | - Emma K. Sisley
- School of Biosciences, University of
Birmingham, Edgbaston B15 2TT, U.K.
| | - Rian L. Griffiths
- School of Biosciences, University of
Birmingham, Edgbaston B15 2TT, U.K.
| | - Iain B. Styles
- School of Computer Science, University of
Birmingham, Edgbaston B15 2TT, U.K.
| | - Helen J. Cooper
- School of Biosciences, University of
Birmingham, Edgbaston B15 2TT, U.K.
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7
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The Interplay between Molten Globules and Heme Disassociation Defines Human Hemoglobin Disassembly. Biophys J 2020; 118:1381-1400. [PMID: 32075750 DOI: 10.1016/j.bpj.2020.01.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/22/2020] [Accepted: 01/27/2020] [Indexed: 12/12/2022] Open
Abstract
Hemoglobin functions as a tetrameric oxygen transport protein, with each subunit containing a heme cofactor. Its denaturation, either in vivo or in vitro, involves autoxidation to methemoglobin, followed by cofactor loss and globin unfolding. We have proposed a global disassembly scheme for human methemoglobin, linking hemin (ferric protoporphyrin IX) disassociation and apoprotein unfolding pathways. The model is based on the evaluation of circular dichroism and visible absorbance measurements of guanidine-hydrochloride-induced disassembly of methemoglobin and previous measurements of apohemoglobin unfolding. The populations of holointermediates and equilibrium disassembly parameters were estimated quantitatively for adult and fetal hemoglobins. The key stages are characterized by hexacoordinated hemichrome intermediates, which are important for preventing hemin disassociation from partially unfolded, molten globular species during early disassembly and late-stage assembly events. Both unfolding experiments and independent small angle x-ray scattering measurements demonstrate that heme disassociation leads to the loss of tetrameric structural integrity. Our model predicts that after autoxidation, dimeric and monomeric hemichrome intermediates occur along the disassembly pathway inside red cells, where the hemoglobin concentration is very high. This prediction suggests why misassembled hemoglobins often get trapped as hemichromes that accumulate into insoluble Heinz bodies in the red cells of patients with unstable hemoglobinopathies. These Heinz bodies become deposited on the cell membranes and can lead to hemolysis. Alternatively, when acellular hemoglobin is diluted into blood plasma after red cell lysis, the disassembly pathway appears to be dominated by early hemin disassociation events, which leads to the generation of higher fractions of unfolded apo subunits and free hemin, which are known to damage the integrity of blood vessel walls. Thus, our model provides explanations of the pathophysiology of hemoglobinopathies and other disease states associated with unstable globins and red cell lysis and also insights into the factors governing hemoglobin assembly during erythropoiesis.
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8
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Manning JM, Manning LR, Dumoulin A, Padovan JC, Chait B. Embryonic and Fetal Human Hemoglobins: Structures, Oxygen Binding, and Physiological Roles. Subcell Biochem 2020; 94:275-296. [PMID: 32189304 DOI: 10.1007/978-3-030-41769-7_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
During the past two decades, significant advances have been made in our understanding of the human fetal and embryonic hemoglobins made possible by the availability of pure, highly characterized materials and novel methods, e.g., nano gel filtration, to study their properties and to correct some misconceptions. For example, whereas the structures of the human adult, fetal, and embryonic hemoglobins are very similar, it has generally been assumed that functional differences between them are due to primary sequence effects. However, more recent studies indicate that the strengths of the interactions between their subunits are very different leading to changes in their oxygen binding properties compared to adult hemoglobin. Fetal hemoglobin in the oxy conformation is a much stronger tetramer than adult hemoglobin and dissociates to dimers 70-times less than adult hemoglobin. This property may form the basis for its protective effect against malaria. A major source of the increased strength of fetal hemoglobin resides within the A-helix of its gamma subunit as demonstrated in studies with the hybrid hemoglobin Felix and related hybrids. Re-activating fetal hemoglobin synthesis in vivo is currently a major focus of clinical efforts designed to treat sickle cell anemia since it inhibits the aggregation of sickle hemoglobin. The mechanisms for both the increased oxygen affinity of fetal hemoglobin and its decreased response to DPG have been clarified. Acetylated fetal hemoglobin, which makes up 10-20% of total fetal hemoglobin, has a significantly weakened tetramer structure suggesting a similar role for other kinds of protein acetylation. Embryonic hemoglobins have the weakest tetramer and dimer structures. In general, the progressively increasing strength of the subunit interfaces of the hemoglobin family during development from the embryonic to the fetal and ultimately to the adult types correlates with their temporal appearance and disappearance in vivo, i.e., ontogeny.
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Affiliation(s)
- James M Manning
- Department of Biology, Northeastern University, Boston, MA, 02115, USA.
| | - Lois R Manning
- Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - Antoine Dumoulin
- Department of Developability, Pierre Fabre Research Centre, Castres, 81106, France
| | - Julio C Padovan
- Laboratory of Gaseous Ion Chemistry, Rockefeller University, New York, NY, 10065, USA
| | - Brian Chait
- Laboratory of Gaseous Ion Chemistry, Rockefeller University, New York, NY, 10065, USA
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9
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Gianquinto E, Moscetti I, De Bei O, Campanini B, Marchetti M, Luque FJ, Cannistraro S, Ronda L, Bizzarri AR, Spyrakis F, Bettati S. Interaction of human hemoglobin and semi-hemoglobins with the Staphylococcus aureus hemophore IsdB: a kinetic and mechanistic insight. Sci Rep 2019; 9:18629. [PMID: 31819099 PMCID: PMC6901573 DOI: 10.1038/s41598-019-54970-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022] Open
Abstract
Among multidrug-resistant bacteria, methicillin-resistant Staphylococcus aureus is emerging as one of the most threatening pathogens. S. aureus exploits different mechanisms for its iron supply, but the preferred one is acquisition of organic iron through the expression of hemoglobin (Hb) receptors. One of these, IsdB, belonging to the Isd (Iron-Regulated Surface Determinant) system, was shown to be essential for bacterial growth and virulence. Therefore, interaction of IsdB with Hb represents a promising target for the rational design of a new class of antibacterial molecules. However, despite recent investigations, many structural and mechanistic details of complex formation and heme extraction process are still elusive. By combining site-directed mutagenesis, absorption spectroscopy, surface plasmon resonance and molecular dynamics simulations, we tackled most of the so far unanswered questions: (i) the exact complex stoichiometry, (ii) the microscopic kinetic rates of complex formation, (iii) the IsdB selectivity for binding to, and extracting heme from, α and β subunits of Hb, iv) the role of specific amino acid residues and structural regions in driving complex formation and heme transfer, and (v) the structural/dynamic effect played by the hemophore on Hb.
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Affiliation(s)
- Eleonora Gianquinto
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy
| | - Ilaria Moscetti
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy
| | - Omar De Bei
- Department of Food and Drug, University of Parma, Parma, 43124, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, Parma, 43124, Italy.,Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy
| | - Marialaura Marchetti
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy.,Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy
| | - F Javier Luque
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB) and Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona, Santa Coloma de Gramenet, 08921, Spain
| | - Salvatore Cannistraro
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy
| | - Luca Ronda
- Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy.,Department of Medicine and Surgery, University of Parma, Parma, 43126, Italy.,Institute of Biophysics, National Research Council, Pisa, 56124, Italy
| | - Anna Rita Bizzarri
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy.
| | - Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy.
| | - Stefano Bettati
- Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy. .,Department of Medicine and Surgery, University of Parma, Parma, 43126, Italy. .,Institute of Biophysics, National Research Council, Pisa, 56124, Italy.
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10
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Meng F, Kassa T, Jana S, Wood F, Zhang X, Jia Y, D’Agnillo F, Alayash AI. Comprehensive Biochemical and Biophysical Characterization of Hemoglobin-Based Oxygen Carrier Therapeutics: All HBOCs Are Not Created Equally. Bioconjug Chem 2018; 29:1560-1575. [DOI: 10.1021/acs.bioconjchem.8b00093] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Fantao Meng
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Tigist Kassa
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Sirsendu Jana
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Francine Wood
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Xiaoyuan Zhang
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Yiping Jia
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Felice D’Agnillo
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Abdu I. Alayash
- Laboratory of Biochemistry and Vascular Biology, Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
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11
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Montioli R, Zamparelli C, Borri Voltattorni C, Cellini B. Oligomeric State and Thermal Stability of Apo- and Holo- Human Ornithine δ-Aminotransferase. Protein J 2017; 36:174-185. [PMID: 28345116 PMCID: PMC5432616 DOI: 10.1007/s10930-017-9710-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Human ornithine δ-aminotransferase (hOAT) (EC 2.6.1.13) is a mitochondrial pyridoxal 5′-phosphate (PLP)-dependent aminotransferase whose deficit is associated with gyrate atrophy, a rare autosomal recessive disorder causing progressive blindness and chorioretinal degeneration. Here, both the apo- and holo-form of recombinant hOAT were characterized by means of spectroscopic, kinetic, chromatographic and computational techniques. The results indicate that apo and holo-hOAT (a) show a similar tertiary structure, even if apo displays a more pronounced exposure of hydrophobic patches, (b) exhibit a tetrameric structure with a tetramer-dimer equilibrium dissociation constant about fivefold higher for the apoform with respect to the holoform, and (c) have apparent Tm values of 46 and 67 °C, respectively. Moreover, unlike holo-hOAT, apo-hOAT is prone to unfolding and aggregation under physiological conditions. We also identified Arg217 as an important hot-spot at the dimer–dimer interface of hOAT and demonstrated that the artificial dimeric variant R217A exhibits spectroscopic properties, Tm values and catalytic features similar to those of the tetrameric species. This finding indicates that the catalytic unit of hOAT is the dimer. However, under physiological conditions the apo-tetramer is slightly less prone to unfolding and aggregation than the apo-dimer. The possible implications of the data for the intracellular stability and regulation of hOAT are discussed.
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Affiliation(s)
- Riccardo Montioli
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy.
| | | | - Carla Borri Voltattorni
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Barbara Cellini
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
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12
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Abstract
Removal of heme from human hemoglobin (Hb) results in formation of an apoglobin heterodimer. Titration of this apodimer with guanidine hydrochloride (GdnHCl) leads to biphasic unfolding curves indicating two distinct steps. Initially, the heme pocket unfolds and generates a dimeric intermediate in which ∼50% of the original helicity is lost, but the α1β1 interface is still intact. At higher GdnHCl concentrations, this intermediate dissociates into unfolded monomers. This structural interpretation was verified by comparing GdnHCl titrations for adult human hemoglobin A (HbA), recombinant fetal human hemoglobin (HbF), recombinant Hb cross-linked with a single glycine linker between the α chains, and recombinant Hbs with apolar heme pocket mutations that markedly stabilize native conformations in both subunits. The first phase of apoHb unfolding is independent of protein concentration, little affected by genetic cross-linking, but significantly shifted toward higher GdnHCl concentrations by the stabilizing distal pocket mutations. The second phase depends on protein concentration and is shifted to higher GdnHCl concentrations by genetic cross-linking. This model for apoHb unfolding allowed us to quantitate subtle differences in stability between apoHbA and apoHbF, which suggest that the β and γ heme pockets have similar stabilities, whereas the α1γ1 interface is more resistant to dissociation than the α1β1 interface.
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Affiliation(s)
- Premila P Samuel
- Department of BioSciences and ‡Department of Chemistry, Rice University , Houston, Texas 77251, United States
| | - William C Ou
- Department of BioSciences and ‡Department of Chemistry, Rice University , Houston, Texas 77251, United States
| | - George N Phillips
- Department of BioSciences and ‡Department of Chemistry, Rice University , Houston, Texas 77251, United States
| | - John S Olson
- Department of BioSciences and ‡Department of Chemistry, Rice University , Houston, Texas 77251, United States
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13
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Bissé E, Schaeffer-Reiss C, Van Dorsselaer A, Alayi TD, Epting T, Winkler K, Benitez Cardenas AS, Soman J, Birukou I, Samuel PP, Olson JS. Hemoglobin Kirklareli (α H58L), a New Variant Associated with Iron Deficiency and Increased CO Binding. J Biol Chem 2016; 292:2542-2555. [PMID: 28011635 DOI: 10.1074/jbc.m116.764274] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/19/2016] [Indexed: 11/06/2022] Open
Abstract
Mutations in hemoglobin can cause a wide range of phenotypic outcomes, including anemia due to protein instability and red cell lysis. Uncovering the biochemical basis for these phenotypes can provide new insights into hemoglobin structure and function as well as identify new therapeutic opportunities. We report here a new hemoglobin α chain variant in a female patient with mild anemia, whose father also carries the trait and is from the Turkish city of Kirklareli. Both the patient and her father had a His-58(E7) → Leu mutation in α1. Surprisingly, the patient's father is not anemic, but he is a smoker with high levels of HbCO (∼16%). To understand these phenotypes, we examined recombinant human Hb (rHb) Kirklareli containing the α H58L replacement. Mutant α subunits containing Leu-58(E7) autoxidize ∼8 times and lose hemin ∼200 times more rapidly than native α subunits, causing the oxygenated form of rHb Kirklareli to denature very rapidly under physiological conditions. The crystal structure of rHb Kirklareli shows that the α H58L replacement creates a completely apolar active site, which prevents electrostatic stabilization of bound O2, promotes autoxidation, and enhances hemin dissociation by inhibiting water coordination to the Fe(III) atom. At the same time, the mutant α subunit has an ∼80,000-fold higher affinity for CO than O2, causing it to rapidly take up and retain carbon monoxide, which prevents denaturation both in vitro and in vivo and explains the phenotypic differences between the father, who is a smoker, and his daughter.
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Affiliation(s)
- Emmanuel Bissé
- From the Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center, Hugstetterstrasse 55, D-79106 Freiburg, Germany
| | - Christine Schaeffer-Reiss
- the BioOrganic Mass Spectrometry Laboratory (LSMBO), IPHC, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg, France.,the IPHC, CNRS, UMR7178, 67087 Strasbourg, France, and
| | - Alain Van Dorsselaer
- the BioOrganic Mass Spectrometry Laboratory (LSMBO), IPHC, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg, France.,the IPHC, CNRS, UMR7178, 67087 Strasbourg, France, and
| | - Tchilabalo Dilezitoko Alayi
- the BioOrganic Mass Spectrometry Laboratory (LSMBO), IPHC, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg, France.,the IPHC, CNRS, UMR7178, 67087 Strasbourg, France, and
| | - Thomas Epting
- From the Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center, Hugstetterstrasse 55, D-79106 Freiburg, Germany
| | - Karl Winkler
- From the Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center, Hugstetterstrasse 55, D-79106 Freiburg, Germany
| | | | - Jayashree Soman
- the BioSciences Department, Rice University, Houston, Texas 77281
| | - Ivan Birukou
- the BioSciences Department, Rice University, Houston, Texas 77281
| | - Premila P Samuel
- the BioSciences Department, Rice University, Houston, Texas 77281
| | - John S Olson
- the BioSciences Department, Rice University, Houston, Texas 77281
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14
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Tidemand KD, Christensen HEM, Hoeck N, Harris P, Boesen J, Peters GH. Stabilization of tryptophan hydroxylase 2 by l-phenylalanine-induced dimerization. FEBS Open Bio 2016; 6:987-999. [PMID: 27761358 PMCID: PMC5055035 DOI: 10.1002/2211-5463.12100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022] Open
Abstract
Tryptophan hydroxylase 2 (TPH2) catalyses the initial and rate‐limiting step in the biosynthesis of serotonin, which is associated with a variety of disorders such as depression, obsessive compulsive disorder, and schizophrenia. Full‐length TPH2 is poorly characterized due to low purification quantities caused by its inherent instability. Three truncated variants of human TPH2 (rchTPH2; regulatory and catalytic domain, NΔ47‐rchTPH2; truncation of 47 residues in the N terminus of rchTPH2, and chTPH2; catalytic domain) were expressed, purified, and examined for changes in transition temperature, inactivation rate, and oligomeric state. chTPH2 displayed 14‐ and 11‐fold higher half‐lives compared to rchTPH2 and NΔ47‐rchTPH2, respectively. Differential scanning calorimetry experiments demonstrated that this is caused by premature unfolding of the less stable regulatory domain. By differential scanning fluorimetry, the unfolding transitions of rchTPH2 and NΔ47‐rchTPH2 are found to shift from polyphasic to apparent two‐state by the addition of l‐Trp or l‐Phe. Analytical gel filtration revealed that rchTPH2 and NΔ47‐rchTPH2 reside in a monomer–dimer equilibrium which is significantly shifted toward dimer in the presence of l‐Phe. The dimerizing effect induced by l‐Phe is accompanied by a stabilizing effect, which resulted in a threefold increase in half‐lives of rchTPH2 and NΔ47‐rchTPH2. Addition of l‐Phe to the purification buffer significantly increases the purification yields, which will facilitate characterization of hTPH2.
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Affiliation(s)
- Kasper D Tidemand
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | | | - Niclas Hoeck
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Pernille Harris
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Jane Boesen
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Günther H Peters
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
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15
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Effects of interface mutations on the dimerization of alanine glyoxylate aminotransferase and implications in the mistargeting of the pathogenic variants F152I and I244T. Biochimie 2016; 131:137-148. [PMID: 27720751 DOI: 10.1016/j.biochi.2016.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/02/2016] [Accepted: 10/02/2016] [Indexed: 11/21/2022]
Abstract
In this work the dimerization process of the minor allelic form of human alanine glyoxylate aminotransferase, a pyridoxal 5'-phosphate enzyme, was investigated. Bioinformatic analyses followed by site-directed mutagenesis, size exclusion chromatography and catalytic activity experiments allowed us to identify Arg118, Phe238 and Phe240 as interfacial residues not essential for transaminase activity but important for dimer-monomer dissociation. The apo and the holo forms of the triple mutant R118A-Mi/F238S-Mi/F240S-Mi display a dimer-monomer equilibrium dissociation constant value at least ~260- and 31-fold larger, respectively, than the corresponding ones of AGT-Mi. In the presence of PLP, the apomonomer of the triple mutant undergoes a biphasic process: the fast phase represents the formation of an inactive PLP-bound monomer, while the slow phase depicts the monomer-monomer association that parallels the regain of transaminase activity. The latter events occur with a rate constant of ~0.02 μM-1min-1. In the absence of PLP, the apomonomer is also able to dimerize but with a rate constant value ~2700-fold lower. Thereafter, the possible interference with the dimerization process of AGT-Mi exerted by the mutated residues in the I244T-Mi and F152I-Mi variants associated with Primary Hyperoxaluria type 1 was investigated by molecular dynamics simulations. On the basis of the present and previous studies, a model for the dimerization process of AGT-Mi, I244T-Mi and F152I-Mi, which outlines the structural defects responsible for the complete or partial mistargeting of the pathogenic variants, was proposed and discussed.
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16
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Storz JF, Natarajan C, Moriyama H, Hoffmann FG, Wang T, Fago A, Malte H, Overgaard J, Weber RE. Oxygenation properties and isoform diversity of snake hemoglobins. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1178-91. [PMID: 26354849 DOI: 10.1152/ajpregu.00327.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/02/2015] [Indexed: 11/22/2022]
Abstract
Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis platura (Elapidae). We analyzed allosteric properties of snake Hbs in terms of the Monod-Wyman-Changeux model and Adair four-step thermodynamic model. Hbs from each of the three species exhibited high intrinsic O2 affinities, low cooperativities, small Bohr factors in the absence of phosphates, and high sensitivities to ATP. Oxygenation properties of the snake Hbs could be explained entirely by allosteric transitions in the quaternary structure of intact tetramers, suggesting that ligation-dependent dissociation of Hb tetramers into αβ-dimers is not a universal feature of snake Hbs. Surprisingly, the major Hb isoform of the South American rattlesnake is homologous to the minor HbD of other amniotes and, contrary to the pattern of Hb isoform differentiation in birds and turtles, exhibits a lower O2 affinity than the HbA isoform.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska;
| | | | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, Mississippi; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, Mississippi; and
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Hans Malte
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Johannes Overgaard
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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17
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Astegno A, Capitani G, Dominici P. Functional roles of the hexamer organization of plant glutamate decarboxylase. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1854:1229-37. [PMID: 25614413 DOI: 10.1016/j.bbapap.2015.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/30/2014] [Accepted: 01/07/2015] [Indexed: 11/20/2022]
Abstract
Glutamate decarboxylase (GAD) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the α-decarboxylation of glutamate to γ-aminobutyrate. A unique feature of plant GAD is the presence of a calmodulin (CaM)-binding domain at its C-terminus. In plants, transient elevation of cytosolic Ca²⁺ in response to different types of stress is responsible for GAD activation via CaM. The crystal structure of GAD isoform 1 from Arabidopsis thaliana (AtGAD1) shows that the enzyme is a hexamer composed of a trimer of dimers. Herein, we show that in solution AtGAD1 is in a dimer-hexamer equilibrium and estimate the dissociation constant (Kd) for the hexamer under different conditions. The association of dimers into hexamers is promoted by several conditions, including high protein concentrations and low pH. Notably, binding of Ca²⁺/CaM1 abolishes the dissociation of the AtGAD1 oligomer. The AtGAD1 N-terminal domain is critical for maintaining the oligomeric state as removal of the first 24 N-terminal residues dramatically affects oligomerization by producing a dimeric enzyme. The deleted mutant retains decarboxylase activity, highlighting the dimeric nature of the basic structural unit of AtGAD1. Site-directed mutagenesis identified Arg24 in the N-terminal domain as a key residue since its mutation to Ala prevents hexamer formation in solution. Both dimeric mutant enzymes form a stable hexamer in the presence of Ca²⁺/CaM1. Our data clearly reveal that the oligomeric state of AtGAD1 is highly responsive to a number of experimental parameters and may have functional relevance in vivo in the light of the biphasic regulation of AtGAD1 activity by pH and Ca²⁺/CaM1 in plant cells. This article is part of a special issue titled "Cofactor-Dependent Proteins: Evolution, Chemical Diversity and Bio-applications."
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Affiliation(s)
- Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, Verona (VR), Italy.
| | | | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, Verona (VR), Italy
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18
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Switching between the Alternative Structures and Functions of a 2-Cys Peroxiredoxin, by Site-Directed Mutagenesis. J Mol Biol 2013; 425:4556-68. [DOI: 10.1016/j.jmb.2013.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/28/2013] [Accepted: 09/02/2013] [Indexed: 12/28/2022]
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19
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Fluorescence Study of the Membrane Effects of Aggregated Lysozyme. J Fluoresc 2013; 23:1229-37. [DOI: 10.1007/s10895-013-1254-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/17/2013] [Indexed: 11/27/2022]
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20
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Propylbenzmethylation at Val-1(α) markedly increases the tetramer stability of the PEGylated hemoglobin: A comparison with propylation at Val-1(α). Biochim Biophys Acta Gen Subj 2012; 1820:2044-51. [DOI: 10.1016/j.bbagen.2012.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 09/15/2012] [Accepted: 09/20/2012] [Indexed: 11/19/2022]
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21
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Manning JM, Popowicz AM, Padovan JC, Chait BT, Manning LR. Intrinsic regulation of hemoglobin expression by variable subunit interface strengths. FEBS J 2011; 279:361-9. [PMID: 22129306 DOI: 10.1111/j.1742-4658.2011.08437.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The expression of the six types of human Hb subunits over time is currently considered to be regulated mainly by transcription factors that bind to upstream control regions of the gene (the 'extrinsic' component of regulation). Here, we describe how subunit pairing and further assembly to tetramers in the liganded state is influenced by the affinity of subunits for one another (the 'intrinsic' component of regulation). The adult Hb dimers have the strongest subunit interfaces and the embryonic Hbs the weakest, with fetal Hbs being of intermediate strength, corresponding to the temporal order of their expression. These variable subunit binding strengths and the attenuating effects of acetylation contribute to the differences with which these Hb types form functional O(2) -binding tetramers consistent with gene switching.
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Affiliation(s)
- James M Manning
- Department of Biology, Northeastern University, Boston, MA 02115, USA.
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22
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Kang Y, Douglas DJ. Gas-phase ions of human hemoglobin A, F, and S. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:1187-1196. [PMID: 21953101 DOI: 10.1007/s13361-011-0138-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/16/2011] [Accepted: 03/18/2011] [Indexed: 05/31/2023]
Abstract
Hemoglobin (Hb) (α(2)β(2)) is a tetrameric protein-protein complex. Collision cross sections, hydrogen exchange levels, and tandem mass spectrometry have been used to investigate the properties of gas-phase monomer, dimer, and tetramer ions of adult human hemoglobin (Hb A, α(2)β(2)), and two variant hemoglobins: fetal hemoglobin (Hb F, α(2)γ(2)) and sickle hemoglobin (Hb S, α(2)β(2), E6V[β]). All three proteins give similar mass spectra. Monomers of Hb S and Hb F have similar cross sections, ca. 10% greater than those of Hb A. Cross sections of dimer ions of Hb S are 11% greater than those of Hb A and 6% greater than those of Hb F. Tetramers of Hb S are 13% larger than tetramers of Hb A or Hb F. Monomers and dimers of all three Hb have similar hydrogen-deuterium exchange (HDX) levels. Tetramers of Hb S exchange 16% more hydrogens than Hb A and Hb F. In tandem mass spectrometry, monomers of Hb S and Hb F require ca. 10% greater internal energy for heme loss than Hb A. Dimers (+11) of Hb A and Hb S dissociate to monomers with asymmetrical charge division; dimers of Hb F (+11) dissociate with nearly equal charge division. Tetramer ions dissociate to monomers and trimers, unlike solution Hb, which dissociates to dimers. The most stable dimers are from Hb S; the most stable tetramers from Hb F. The results with Hb S show that a single mutation in the β chain can change the physical properties of this gas-phase protein-protein complex.
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Affiliation(s)
- Yang Kang
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
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23
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Manning LR, Popowicz AM, Padovan J, Chait BT, Russell JE, Manning JM. Developmental expression of human hemoglobins mediated by maturation of their subunit interfaces. Protein Sci 2010; 19:1595-9. [PMID: 20572018 DOI: 10.1002/pro.441] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Different types of human hemoglobins (Hbs) consisting of various combinations of the embryonic, fetal, and adult Hb subunits are present at certain times during development representing a major paradigm of developmental biology that is still not understood and one which we address here. We show that the subunit interfaces of these Hbs have increasing bonding strengths as demonstrated by their distinct distribution of tetramers, dimers, and monomers during gel filtration at very low-Hb concentration. This maturation is mediated by competition between subunits for more favorable partners with stronger subunit interactions. Thus, the protein products of gene expression can themselves have a role in the developmental process due to their intrinsic properties.
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Affiliation(s)
- Lois R Manning
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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24
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25
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Hu T, Li D, Meng F, Prabhakaran M, Acharya SA. Increased Inter Dimeric Interaction of Oxy Hemoglobin is Necessary for Attenuation of Redutive Pegylation Promoted Dissociation of Tetramer. ACTA ACUST UNITED AC 2010; 39:69-78. [DOI: 10.3109/10731199.2010.501756] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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26
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Galvagnion C, Smith MTJ, Broom A, Vassall KA, Meglei G, Gaspar JA, Stathopulos PB, Cheyne B, Meiering EM. Folding and association of thermophilic dimeric and trimeric DsrEFH proteins: Tm0979 and Mth1491. Biochemistry 2009; 48:2891-906. [PMID: 19290646 DOI: 10.1021/bi801784d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although the majority of natural proteins exist as protein-protein complexes, the molecular basis for the formation and regulation of such interactions and the evolution of protein interfaces remain poorly understood. We have investigated these phenomena by characterizing the thermal and chemical denaturation of thermophilic DsrEFH proteins that have a common subunit fold but distinct quaternary structures: homodimeric Tm0979 and homotrimeric Mth1491. Tm0979 forms a moderate affinity dimer, and a monomeric intermediate is readily populated at equilibrium and during folding kinetics. In contrast, the Mth1491 trimer has extremely high stability, so that a monomeric form is not measurably populated at equilibrium, although it may be during folding kinetics. A common mechanism for evolution of quaternary structures may be facile formation of a relatively stable monomeric species, with stabilizing intermolecular interactions centering on alternative environments for a beta-strand at the edge of the monomer, augmented by malleable hydrophobic interactions. The exceptional trimer stability arises from a remarkably slow unfolding rate constant, 6.5 x 10(-13) s(-1), which is a common characteristic of highly stable thermophilic and/or oligomeric proteins. The folding characteristics of Tm0979 and Mth1491 have interesting implications for assembly and regulation of homo- and heterooligomeric proteins in vivo.
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Affiliation(s)
- Céline Galvagnion
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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27
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Li D, Hu T, Manjula BN, Acharya SA. Extension Arm Facilitated Pegylation of αα-Hemoglobin with Modifications Targeted Exclusively to Amino Groups: Functional and Structural Advantages of Free Cys-93(β) in the PEG-Hb Adduct. Bioconjug Chem 2009; 20:2062-70. [DOI: 10.1021/bc900170e] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dongxia Li
- Departments of Physiology and Biophysics, and of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Tao Hu
- Departments of Physiology and Biophysics, and of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Belur N. Manjula
- Departments of Physiology and Biophysics, and of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Seetharama A. Acharya
- Departments of Physiology and Biophysics, and of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
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28
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Pimenova T, Pereira CP, Schaer DJ, Zenobi R. Characterization of high molecular weight multimeric states of human haptoglobin and hemoglobin-based oxygen carriers by high-mass MALDI MS. J Sep Sci 2009; 32:1224-30. [DOI: 10.1002/jssc.200800625] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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29
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Hu T, Li D, Manjula BN, Brenowitz M, Prabhakaran M, Acharya SA. PEGylation of Val-1(alpha) destabilizes the tetrameric structure of hemoglobin. Biochemistry 2009; 48:608-16. [PMID: 19119852 DOI: 10.1021/bi801880y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A hexaPEGylated hemoglobin (Hb), (Propyl-PEG5K)(6)-Hb, is essentially in alphabeta dimers (Hu et al. (2007) Biochem. J. 402, 143-151). In order to provide a biochemical insight into the tetramer-dimer dissociation of this PEGylated Hb, we prepared and characterized two PEGylated Hbs site-specifically modified at Val-1(alpha) and at Val-1(beta), respectively. PEGylation at Val-1(alpha) and at Val-1(beta) increase the tetramer-dimer dissociation constant (K(d)) of Hb by 2 and 1 order of magnitude, respectively. Accordingly, the sites of PEGylation can determine the tetramer stability of the PEGylated Hb. In order to determine the role of the polyethylene glycol (PEG) chains on the tetramer stability of Hb, we prepared a propylated Hb site-specifically modified at Val-1(alpha). Interestingly, site-specific propylation of Hb at Val-l(alpha) stabilizes the Hb tetramer by 1 order of magnitude. Therefore, conjugation of the PEG chains at Val-1(alpha) can greatly destabilize the tetramer stability of Hb. On the structural aspects, the PEG chains conjugated at Va-1(alpha) unfavorably alter the heme environment and quaternary structure and destabilize the alpha1beta2 interface of Hb. On the functional aspects, the PEG chains conjugated at Val-1(alpha) decrease the Hill coefficient, the Bohr effect of Hb and the sensitization to the presence of the allosteric effectors. In contrast, PEGylation of Hb at Val-1(beta) gives rise to less pronounced structural alteration and different functional change.
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Affiliation(s)
- Tao Hu
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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30
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Manning LR, Russell JE, Padovan JC, Chait BT, Popowicz A, Manning RS, Manning JM. Human embryonic, fetal, and adult hemoglobins have different subunit interface strengths. Correlation with lifespan in the red cell. Protein Sci 2007; 16:1641-58. [PMID: 17656582 PMCID: PMC2203358 DOI: 10.1110/ps.072891007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The different types of naturally occurring, normal human hemoglobins vary in their tetramer-dimer subunit interface strengths (stabilities) by three orders of magnitude in the liganded (CO or oxy) state. The presence of embryonic zeta-subunits leads to an average 20-fold weakening of tetramer-dimer interfaces compared to corresponding hemoglobins containing adult alpha-subunits. The dimer-monomer interfaces of these hemoglobins differ by at least 500-fold in their strengths; such interfaces are weak if they contain zeta-subunits and exchange with added beta-subunits in the form of beta(4) (HbH) significantly faster than do those with alpha-subunits. Subunit exchange occurs at the level of the dimer, although tetramer formation reciprocally influences the amount of dimer available for exchange. Competition between subunit types occurs so that pairs of weak embryonic hemoglobins can exchange subunits to form the stronger fetal and adult hemoglobins. The dimer strengths increase in the order Hb Portland-2 (zeta(2)beta(2)) < Hb Portland-1 (zeta(2)gamma(2)) approximately equal Hb Gower-1 (zeta(2)epsilon(2)) < Hb Gower-2 (alpha(2)epsilon(2)) < HbF(1) < HbF (alpha(2)gamma(2)) < HbA(2) (alpha(2)delta(2)), i.e., from embryonic to fetal to adult types, representing maturation from weaker to stronger monomer-monomer subunit contacts. This increasing order recapitulates the developmental order in which globins are expressed (embryonic --> fetal --> adult), suggesting that the intrinsic binding properties of the subunits themselves regarding the strengths of interfaces they form with competing subunits play an important role in the dynamics of protein assemblies and networks.
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Affiliation(s)
- Lois R Manning
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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31
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Stenmark P, Ogg D, Flodin S, Flores A, Kotenyova T, Nyman T, Nordlund P, Kursula P. The structure of human collapsin response mediator protein 2, a regulator of axonal growth. J Neurochem 2006; 101:906-17. [PMID: 17250651 DOI: 10.1111/j.1471-4159.2006.04401.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Axonal growth cone guidance is a central process in nervous system development and repair. Collapsin response mediator protein 2 (CRMP-2) is a neurite extension-promoting neuronal cytosolic molecule involved in the signalling of growth inhibitory cues from external stimuli, such as semaphorin 3A and the myelin-associated glycoprotein. We have determined the crystal structure of human tetrameric CRMP-2, which is structurally related to the dihydropyriminidases; however, the active site is not conserved. The wealth of earlier functional mapping data for CRMP-2 are discussed in light of the three-dimensional structure of the protein. The differences in oligomerisation interfaces between CRMP-1 and CRMP-2 are used to model CRMP-1/2 heterotetramers.
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Affiliation(s)
- Pål Stenmark
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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32
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David R, Beck-Sickinger AG. Identification of the dimerisation interface of human interleukin-8 by IL-8-variants containing the photoactivatable amino acid benzoyl-phenylalanine. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 36:385-91. [PMID: 17024463 DOI: 10.1007/s00249-006-0100-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Revised: 07/26/2006] [Accepted: 08/25/2006] [Indexed: 11/29/2022]
Abstract
The three-dimensional structure of human interleukin-8 (hIL-8) was determined by the use of NMR and X-ray methodology. At high concentrations interleukin-8 and many other chemokines form a non-covalent homodimer. Several studies have been performed to investigate the relevance of the dimer on receptor activation and led to contradictory results. In order to obtain a better understanding of the dimerisation process, covalently linked homo- and heterodimers were produced by photo-induced dimerisation of hIL-8 analogues that contain the photo-activatable amino acid p-benzoyl-phenylalanine (Bpa) at different positions. Whereas the N-terminal fragment (1-54) was expressed as recombinant thioester, the C-terminal fragments (55-77) that contain Bpa either at position 65 or 74 were obtained by solid-phase peptide synthesis. The segments were combined by expressed protein ligation and led to full length IL-8 variants containing the non-proteinogenic amino acid Bpa at single positions. IP(3) activity tests showed high biological activity for the CXCR1-GFP receptor for both variants comparable to that of the native ligand. The refolded and purified ligation-products were used for dimer formation by UV-irradiation. The analysis of the reaction mixture was performed by gel-electrophoresis and mass spectrometry and showed that dimer formation of IL-8 occurred in a position dependent manner. [Bpa(74)]hIL-8 has a high tendency to form covalent dimers whereas no dimer formation was observed for the variant with Bpa at position 65. Accordingly one residue of the dimerisation interface could be identified.
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Affiliation(s)
- Ralf David
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany
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Grunwald EW, Richards MP. Studies with myoglobin variants indicate that released hemin is the primary promoter of lipid oxidation in washed fish muscle. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:4452-60. [PMID: 16756380 DOI: 10.1021/jf0603228] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Variants of sperm whale myoglobin (Mb) were used to assess the mechanism of heme protein-mediated lipid oxidation in washed cod muscle. A myoglobin variant with high hemin affinity (V68T) was an exceptionally poor promoter of lipid oxidation, while a Mb variant with low hemin affinity (H97A) was a potent promoter of lipid oxidation. V68T releases hemin slowly due to the ability of threonine to hydrogen bond with coordinated water and the distal histidine within the heme crevice. H97A rapidly releases hemin because the relatively small alanine residue creates a channel for water to easily enter the heme crevice which weakens the covalent linkage of hemin to the proximal histidine. A variant sensitive to heme degradation (L29F/H64Q) was a weaker promoter of lipid oxidation compared to wild-type Mb. This suggests that degrading the heme ring and releasing iron decreased the ability of Mb to promote lipid oxidation. Free radicals resulting from hemin-mediated decomposition of lipid hydroperoxides have the capacity to propagate lipid oxidation and degrade hemin catalyst. This may explain why heme proteins behave as reactants rather than "catalysts" of lipid oxidation in washed cod. Collectively these studies strongly suggest that released hemin is the critical entity that drives heme protein-mediated lipid oxidation in washed fish muscle.
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Affiliation(s)
- Eric W Grunwald
- Meat Science and Muscle Biology Laboratory, Department of Animal Sciences, University of Wisconsin-Madison, 1805 Linden Drive West, Madison, Wisconsin 53706, USA
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Vasseur-Godbillon C, Hamdane D, Marden MC, Baudin-Creuza V. High-yield expression in Escherichia coli of soluble human α-hemoglobin complexed with its molecular chaperone. Protein Eng Des Sel 2006; 19:91-7. [PMID: 16390839 DOI: 10.1093/protein/gzj006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The alpha-subunits of human hemoglobin (Hb) have been more difficult to express than beta-chains owing to the high instability of alpha-chains. Here, we describe the production in Escherichia coli of a soluble recombinant alpha-Hb with human alpha-hemoglobin-stabilizing protein (AHSP), its molecular chaperone. To succeed in this expression, we have constructed a vector pGEX-alpha-AHSP which contains two cassettes arranged in tandem in the same orientation permitting to express alpha-hemoglobin and human AHSP. While the GST-alpha-Hb alone was expressed in E.coli as insoluble protein, even after adding lysate containing recombinant AHSP, the expression vector pGEX-alpha-AHSP permits the co-expression of soluble GST-alpha-Hb and GST-AHSP. The alpha-Hb, produced at a high yield of 12 to 20 mg per liter of culture, was then purified as a complex with its chaperone. Biochemical and biophysical properties of recombinant AHSP/recombinant alpha-Hb complex were similar to those of recombinant AHSP/native alpha-Hb complex as assessed by UV/visible and CO or O(2) binding properties. This co-expression technique can be use to study the interaction between a molecular chaperone and its target protein and, more generally, this system would be particularly interesting for the study of partner proteins when one or both proteins are individually unstable.
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Lee HS, Kim JS, Shim K, Kim JW, Inouye K, Oneda H, Kim YW, Cheong KA, Cha H, Woo EJ, Auh JH, Lee SJ, Kim JW, Park KH. Dissociation/association properties of a dodecameric cyclomaltodextrinase. Effects of pH and salt concentration on the oligomeric state. FEBS J 2006; 273:109-21. [PMID: 16367752 DOI: 10.1111/j.1742-4658.2005.05047.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
As an effort to elucidate the quaternary structure of cyclomaltodextrinase I-5 (CDase I-5) as a function of pH and salt concentration, the dissociation/association processes of the enzyme were investigated under various pH and salt conditions. Previous crystallographic analysis of CDase I-5 indicated that it existed exclusively as a dodecamer at pH 7.0, forming an assembly of six 3D domain-swapped dimeric subunits. In the present study, analytical ultracentrifugation analysis suggested that CDase I-5 was present as a dimer in the pH range of 5.0-6.0, while the dodecameric form was predominant at pH values above 6.5. No dissociation of the dodecamer was observed at pH 7.0 and the above. Gel filtration chromatography showed that CDase I-5 dissociated into dimers at a rate of 8.58 x 10(-2) h(-1) at pH 6.0. A mutant enzyme with three histidine residues (H49, H89, and H539) substituted with valines dissociated into dimers faster than the wild-type enzyme at both pH 6.0 and 7.0. The tertiary structure indicated that the effect of pH on dissociation of the oligomer was mainly due to the protonation of H539. Unlike the pH-dependent process, the dissociation of wild-type CDase I-5 proceeded very fast at pH 7.0 in the presence of 0.2-1.0 M of KCl. Stopped-flow spectrophotometric analysis at various concentrations of KCl showed that the rate constants of dissociation (kd) from dodecamers into dimers were 5.96 s(-1) and 7.99 s(-1) in the presence of 0.2 M and 1.0 M of KCl, respectively.
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Affiliation(s)
- Hee-Seob Lee
- Center for Agricultural Biomaterials, and School of Agricultural Biotechnology, Seoul National University, Seoul, Korea
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36
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Richards MP, Dettmann MA, Grunwald EW. Pro-oxidative characteristics of trout hemoglobin and myoglobin: a role for released heme in oxidation of lipids. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:10231-8. [PMID: 16366720 DOI: 10.1021/jf051923m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The molecular mass of trout myoglobin was 16017 Da based on electrospray ionization mass spectrometry. A Root effect (low oxygen affinity at pH 6.3) was determined in trout hemoglobin but not myoglobin. At pH 6.3, myoglobin autoxidized more rapidly (3.5-fold) as compared to anodic hemoglobin. Anodic hemoglobin was a better catalyst of lipid oxidation in washed cod muscle as compared to myoglobin at pH 6.3. This suggested that some process other than met heme protein formation was the rate-limiting step in lipid oxidation processes. Heme loss rates were determined using the apomyoglobin mutant H64Y prepared from sperm whale. Anodic hemoglobin released its heme group much more rapidly than myoglobin. In comparisons of anodic and cathodic hemoglobins, heme loss rate better predicted the onset of lipid oxidation than autoxidation rate. These studies collectively suggest that heme dissociation has a primary role in the ability of different heme proteins to promote lipid oxidation processes.
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Affiliation(s)
- Mark P Richards
- Meat Science and Muscle Biology Laboratory, Department of Animal Sciences, University of Wisconsin--Madison, 1805 Linden Drive West, Madison, Wisconsin 53706, USA.
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Ashiuchi M, Yagami T, Willey RJ, Padovan JC, Chait BT, Popowicz A, Manning LR, Manning JM. N-terminal acetylation and protonation of individual hemoglobin subunits: position-dependent effects on tetramer strength and cooperativity. Protein Sci 2005; 14:1458-71. [PMID: 15929996 PMCID: PMC2253374 DOI: 10.1110/ps.041267405] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The presence of alanine (Ala) or acetyl serine (AcSer) instead of the normal Val residues at the N-terminals of either the alpha- or the beta-subunits of human adult hemoglobin confers some novel and unexpected features on the protein. Mass spectrometric analysis confirmed that these substitutions were correct and that they were the only ones. Circular dichroism studies indicated no global protein conformational changes, and isoelectric focusing showed the absence of impurities. The presence of Ala at the N-terminals of the alpha-subunits of liganded hemoglobin results in a significantly increased basicity (increased pK(a) values) and a reduction in the strength of subunit interactions at the allosteric tetramer-dimer interface. Cooperativity in O(2) binding is also decreased. Substitution of Ala at the N-terminals of the beta-subunits gives neither of these effects. The substitution of Ser at the N terminus of either subunit leads to its complete acetylation (during expression) and a large decrease in the strength of the tetramer-dimer allosteric interface. When either Ala or AcSer is present at the N terminus of the alpha-subunit, the slope of the plot of the tetramer-dimer association/dissociation constant as a function of pH is decreased by 60%. It is suggested that since the network of interactions involving the N and C termini of the alpha-subunits is less extensive than that of the beta-subunits in liganded human hemoglobin disruptions there are likely to have a profound effect on hemoglobin function such as the increased basicity, the effects on tetramer strength, and on cooperativity.
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Affiliation(s)
- Makoto Ashiuchi
- Department of Biology, Mugar Life Sciences Building, Room 134, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
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Ioanitescu AI, Dewilde S, Kiger L, Marden MC, Moens L, Van Doorslaer S. Characterization of nonsymbiotic tomato hemoglobin. Biophys J 2005; 89:2628-39. [PMID: 16040738 PMCID: PMC1366763 DOI: 10.1529/biophysj.105.060582] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The nonsymbiotic tomato hemoglobin SOLly GLB1 (Solanum lycopersicon) is shown to form a homodimer of approximately 36 kDa with a high affinity for oxygen. Furthermore, our combined ultraviolet/visible, resonance Raman, and continuous wave electron paramagnetic resonance (EPR) measurements reveal that a mixture of penta- and hexacoordination of the heme iron is found in the deoxy ferrous form, whereas the ferric form shows predominantly a bis-histidine ligation (F8His-Fe(2+/3+)-E7His). This differs from the known forms of vertebrate hemoglobins and myoglobins. We have successfully applied our recently designed pulsed-EPR strategy to study the low-spin ferric form of tomato hemoglobin. These experiments reveal that, in ferric SOLly GLB1, one of the histidine planes is rotated 20 degrees (+/-10 degrees ) away from a N(heme)-Fe-N(heme) axis. Additionally, the observed g-values indicate a quasicoplanarity of the histidine ligands. From the HYSCORE (hyperfine sublevel correlation) measurements, the hyperfine and nuclear quadrupole couplings of the heme and histidine nitrogens are identified and compared with known EPR/ENDOR data of vertebrate Hbs and cytochromes. Finally, the ligand binding kinetics, which also indicate that the ferrous tomato Hb is only partially hexacoordinated, will be discussed in relation with the heme-pocket structure. The similarities and differences with other known nonsymbiotic plant hemoglobins will be highlighted.
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Affiliation(s)
- A Iulia Ioanitescu
- Departments of Physics and Biomedical Sciences, University of Antwerp, Antwerp, Belgium
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Geva A, Clark JJ, Zhang Y, Popowicz A, Manning JM, Neufeld EJ. Hemoglobin Jamaica plain--a sickling hemoglobin with reduced oxygen affinity. N Engl J Med 2004; 351:1532-8. [PMID: 15470216 DOI: 10.1056/nejmoa040771] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A baby girl presented with symptomatic sickle cell disease exacerbated by mild hypoxemia, despite a newborn-screening diagnosis of sickle cell trait. DNA sequencing of the beta globin gene revealed that her maternal beta globin allele was normal. Her paternal allele had not only the expected sickle-trait mutation, betaGlu6Val, but also a second, charge-neutral mutation, betaLeu68Phe. Analysis of the patient's hemoglobin revealed that the double-mutant protein, which we called "hemoglobin Jamaica Plain," had severely reduced oxygen affinity. Structural modeling suggested destabilization of the oxy conformation as a molecular mechanism for sickling in a heterozygote at an ambient partial pressure of oxygen.
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Affiliation(s)
- Alon Geva
- Division of Hematology-Oncology, Children's Hospital Boston, MA 02115, USA
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40
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Baudin-Creuza V, Vasseur-Godbillon C, Pato C, Préhu C, Wajcman H, Marden MC. Transfer of Human α- to β-Hemoglobin via Its Chaperone Protein. J Biol Chem 2004; 279:36530-3. [PMID: 15220346 DOI: 10.1074/jbc.m405389200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha-hemoglobin-stabilizing protein (AHSP), a small protein of 102 amino acids, is synthesized in red blood cell precursors. It binds specifically to alpha-hemoglobin (alpha-Hb) subunits acting as a chaperone protein, preventing the formation of alpha-hemoglobin-cytotoxic precipitates. We have engineered recombinant AHSP in a pGEX vector to study the functional consequence of interaction between AHSP and alpha-Hb. By in vitro binding assays, we have isolated the complexes glutathione S-transferase-AHSP.alpha-Hb and AHSP.alpha-Hb. The latter assembles as a heterodimer based on size-exclusion chromatography. These complexes exhibited monophasic CO binding kinetics, as observed for isolated alpha- and beta-subunits of hemoglobin. However, the rate of CO (or oxygen) binding to alpha-hemoglobin bound to its chaperone is three times slower than that observed for isolated alpha-hemoglobin, demonstrating a form that is intermediate to the R- and T-hemoglobin states. The physiologically relevant replacement of the chaperone by beta-hemoglobin chains could be detected by both ligand binding kinetics and tryptophan fluorescence quenching.
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41
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Fablet C, Marden MC, Green BN, Ho C, Pagnier J, Baudin-Creuza V. Stable octameric structure of recombinant hemoglobin alpha(2)beta(2)83 Gly-->Cys. Protein Sci 2003; 12:690-5. [PMID: 12649426 PMCID: PMC2323840 DOI: 10.1110/ps.0234403] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have engineered a recombinant hemoglobin (rHb betaG83C) based on the variant Hb Ta-Li, which oligomerizes through intertetramer disulfide bonds. Size exclusion chromatography and electrospray ionization mass spectrometry show that the rHb betaG83C assembles into an oligomeric structure the size of a dimer of tetramers. The oligomer has carbon monoxide-binding properties similar to those of natural human hemoglobin. Unlike HbA, the oligomer does not participate in dimer exchange. The CO kinetics, auto-oxidation rate, and gel filtration experiments on the oligomeric betaG83C did not show the usual concentration dependence, implying that it does not dissociate easily into smaller species. The octamer could be dissociated by the use of reducing agents. The action of reduced glutathione on oligomeric betaG83C exhibited biphasic kinetics for the loss of the octameric form, with a time constant for the rapid phase of about 2 h at 1 mM glutathione. However, the size of oligomer betaG83C was not modified after incubation with fresh plasma.
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Baudin-Creuza V, Vasseur-Godbillon C, Kister J, Domingues E, Poyart C, Marden M, Pagnier J. Importance of helices A and H in oxygen binding differences between bovine and human hemoglobins. Hemoglobin 2002; 26:373-84. [PMID: 12484632 DOI: 10.1081/hem-120016374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Human and bovine hemoglobins (Hbs) exhibit several functional differences. They have a similar oxygen affinity in the presence of 2,3-diphosphoglycerate (2,3-DPG); however, bovine Hb has a greatly diminished 2,3-DPG effect, which itself is chloride dependent. The question is to determine whether these differences have a common structural origin, or whether they evolved in an independent fashion. The decreased 2,3-DPG effect can be partially reproduced by mutations at the effector binding sites, substituting the betaNA1 valine-NA2 histidine present in human Hb with a methionine. While changes of human Hb at these sites could provoke the bovine characteristic of the lower 2,3-DPG effect, the oxygen affinities of these mutated Hbs were not as low as that of the bovine Hb. Modifications responsible for tertiary structural modifications of helix A in human Hb might help shift the N-terminal methionine position, thereby locking helix A in place. We replaced the residues proline beta5(A2), arginine beta104(G6), and tyrosine beta130(H8) of human Hb by the residues present in bovine beta-globin, namely alanine, lysine, and phenylalanine, respectively. These mutations did not allow us to obtain a low oxygen affinity recombinant Hb (rHb). This indicates that other factors also influence oxygen binding and the effects are only partially coupled.
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Affiliation(s)
- Véronique Baudin-Creuza
- Institut National de la Santé et de la Recherche Médicale Unité 473, 84, rue du Général Leclerc, 94276 Le Kremlin-Bicêtre, France.
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Li X, Briehl RW, Bookchin RM, Josephs R, Wei B, Manning JM, Ferrone FA. Sickle hemoglobin polymer stability probed by triple and quadruple mutant hybrids. J Biol Chem 2002; 277:13479-87. [PMID: 11782463 DOI: 10.1074/jbc.m108149200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
As part of an effort to understand the interactions in HbS polymerization, we have produced and studied a recombinant triple mutant, D6A(alpha)/D75Y(alpha)/E121R(beta), and a quadruple mutant comprising the preceding mutation plus the natural genetic mutation of sickle hemoglobin, E6V(beta). These recombinant hemoglobins expressed in yeast were extensively characterized, and their structure and oxygen binding cooperativity were found to be normal. Their tetramer-dimer dissociation constants were within a factor of 2 of HbA and HbS. Polymerization of these mutants mixed with HbS was investigated by a micromethod based on volume exclusion by dextran. The elevated solubility of mixtures of HbS with HbA and HbF in dextran could be accurately predicted without any variable parameters. Relative to HbS, the copolymerization probability of the quadruple mutant/HbS hybrid was found to be 6.2, and the copolymerization probability for the triple mutant/HbS hybrid was 0.52. The pure quadruple mutant had a solubility slightly above that of its hybrid with HbS. One way to explain these results is to require significant cis-trans differences in the polymer and that HbA assemble above 42.5 g/dl. A second way to explain these data is by the modification of motional freedom, thereby changing vibrational entropy in the polymer.
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Affiliation(s)
- Xianfeng Li
- Department of Biochemistry, Northeastern University, Boston, Massachusetts 02115, USA
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44
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Kluger R. 2001 Lemieux Award Lecture Organic chemistry and hemoglobin: Benefits from controlled alteration. CAN J CHEM 2002. [DOI: 10.1139/v01-200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hemoglobin carries oxygen in circulation within red cells but does not function outside the cells because it fails not only to release oxygen but also dissociates into dimers that make up the tetrameric protein. Bifunctional anionic acylating agents that contain a structurally rigid bridge introduce cross-links that stabilize hemoglobin and alter its oxygen affinity so that it could be used to carry oxygen outside cells. Nitric oxide binds to hemoglobin and in circulation this causes undesirable increases in blood pressure. It had been reported that higher weight collections of hemoglobin do not cause vasoconstriction. Reagents with two pairs of reaction sites joined by a rigid link connect and cross-link two hemoglobins. The resulting bis-tetramers lack the cooperativity of the native protein and bind oxygen too tightly to be useful; occupation by oxygen blocks the sites from nitric oxide. Nitric oxide may be delivered from thionitrosyl groups, which occur in hemoglobin in the red cell. Cross-linked hemoglobin can be specifically nitrosylated. These species can then serve as circulating sources of nitric oxide resulting from an internal electron transfer.Key words: proteins, hemoglobin, cross-link, red cells, cooperativity, connecting.
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Yagami T, Ballard BT, Padovan JC, Chait BT, Popowicz AM, Manning JM. N-terminal contributions of the gamma-subunit of fetal hemoglobin to its tetramer strength: remote effects at subunit contacts. Protein Sci 2002; 11:27-35. [PMID: 11742119 PMCID: PMC2368781 DOI: 10.1110/ps.30602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The greatly increased tetramer strength of liganded fetal hemoglobin compared with adult hemoglobin is shown by its 70-fold smaller tetramer-dimer dissociation constant. This property has been shown previously to be only partially caused by the 5-amino-acid differences at both types of interfaces in each hemoglobin. A major contributor to tetramer strengthening is the 18-amino-acid N-terminal A helix of the gamma-subunit of fetal hemoglobin, which differs from the beta-subunit of adult hemoglobin at eight amino acid residues. This long-distance communication between the A helix and the distant C helix and FG helical corner comprising the subunit contacts at the allosteric interface represents internal signaling. Physiologically, its greater tetramer strength endows fetal hemoglobin with the capacity to abstract oxygen from maternal adult hemoglobin. It also leads to resistance of fetal red cells to the malaria parasite because the HbF tetramer does not dissociate to dimers as readily as HbA; dimers are digested by malaria proteases but tetramers are not. In this communication, we report which sites on the A helix of the gamma-subunit are important for tetramer strengthening in HbF by substituting certain amino acids in the beta-subunit by the corresponding residues in the gamma-subunit. The recombinant hemoglobins containing up to five replacements together have been extensively characterized. Mass values were within 1 unit of theory. Gly 1 (gamma) of HbF with its high pK(a) of 8.1 compared with a 7.1 value for Val 1 (beta) of HbA creates a highly electropositive N terminus that may couple with the electronegative sequence just after it on the gamma-subunit. The Leu 3 to Phe replacement has no apparent role; however, position 5 is important because replacement of Pro 5 (beta) by Glu 5 (gamma) promotes tetramer strengthening. The Glu --> Asp replacement at position 7 enhances this effect because of the lower pK(a) of Asp but the Val --> Ile substitution at position 11 has no effect. Thus, the three positive/negative sites at positions 1, 5, and 7 account for practically all of the tetramer strength of HbF, as illustrated by an electrostatic surface potential analysis. The pathway by which information is transmitted to the distant allosteric subunit interfaces is currently under study. Oxygen-binding properties of the hemoglobins with charged substitutions more closely resemble those of HbA rather than those of HbF. Thus, whereas the A helix has a major role in controlling the strength of interactions at the tetramer-dimer allosteric interface, oxygen-binding properties of HbA and HbF are influenced by sequences in the C helix and at the FG helical corner constituting the allosteric interface.
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Affiliation(s)
- Takeshi Yagami
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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46
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Baudin-Creuza V, Fablet C, Zal F, Green BN, Promé D, Marden MC, Pagnier J, Wajcman H. Hemoglobin Porto Alegre forms a tetramer of tetramers superstructure. Protein Sci 2002; 11:129-36. [PMID: 11742129 PMCID: PMC2368782 DOI: 10.1110/ps.35702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The effects of the mutation beta9(A6)Ser --> Cys on the interactions between the human hemoglobin molecules were investigated, and comparisons were made with other variants having an additional cysteine residue. In hemoglobin Porto Alegre (PA), the beta9 mutation induces polymerization by forming interchain disulfide bonds via the extra cysteine. The hemolysate from a heterozygote was separated by gel filtration into a tetrameric fraction and a higher-molecular-weight oligomeric fraction (30%). Reversed-phase high-performance liquid chromatography and electrospray ionization mass spectrometry (ESI-MS) under denaturing conditions showed that the tetrameric fraction contained only normal alpha- and beta-chains, whereas the oligomeric fraction contained only normal alpha-chain and disulfide-linked beta(PA) dimer. Under native conditions, ESI-MS of the oligomeric fraction revealed a principal complex of mass 258,400 Da corresponding to a tetramer of tetramers, and 10% of minor components. Transmission electron microscopy corroborated this structure by showing four spheres of 140 A diameter surrounding a central cavity. Equilibrium experiments on the oligomer at different concentrations, using gel filtration and dimer exchange experiments with metHbA-CN, showed that the tetramer of tetramers dissociates into smaller species, probably by breaking the dimer-dimer allosteric interface. None of the other variants investigated formed such a large oligomer.
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47
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Dorfman R, Walsh PN. Noncovalent interactions of the Apple 4 domain that mediate coagulation factor XI homodimerization. J Biol Chem 2001; 276:6429-38. [PMID: 11092900 DOI: 10.1074/jbc.m010340200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Apple 4 (A4) domain of human plasma factor XI (FXI) was used to investigate the process of FXI noncovalent dimer formation. Recombinant 6-histidine-tagged A4 domain proteins were prepared utilizing a bacterial expression system. Purification was accomplished under denaturing conditions, followed by a refolding protocol to facilitate correct disulfide bond formation. Analysis of the A4 domain (C321S mutant) by size exclusion chromatography indicated the presence of a slowly equilibrating reversible monomer-dimer equilibrium. The elution profiles reveal highly symmetrical peaks for both dimeric and monomeric species with elution times that were highly reproducible for varying amounts of both the dimeric and monomeric species. The monomer-dimer equilibrium was found to be dependent upon changes in both pH and salt concentration. Under conditions approximating physiologic salt concentration and pH (20 mm HEPES, 100 mm NaCl, and 1 mm EDTA, pH 7.4), it was determined that the monomer-dimer equilibrium was characterized by a dissociation constant (K(D)) value of 229 +/- 26 nm with a calculated Delta G value of 9.1 kcal/mol. This report identifies electrostatic contributions and the presence of a hydrophobic component that mediate interactions at the A4 domain interface. The rate of dissociation for the recombinant A4 domain C321S mutant was examined by monitoring the increase in 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid dipotassium salt fluorescence under dissociating conditions, giving a value for a dissociation rate constant (k(off)) of 4.3 x 10(-3) s(-1).
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Affiliation(s)
- R Dorfman
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Metzler DE, Metzler CM, Sauke DJ. How Macromolecules Associate. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50010-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Inagaki K, Inagaki J, Dumoulin A, Padovan JC, Chait BT, Popowicz A, Manning LR, Manning JM. Expression and properties of recombinant HbA2 (alpha2delta2) and hybrids containing delta-beta sequences. JOURNAL OF PROTEIN CHEMISTRY 2000; 19:649-62. [PMID: 11307949 DOI: 10.1023/a:1007196118200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hemoglobin A2 (alpha2delta2), which is present at low concentration (1-2%) in the circulating red cells of normal individuals, has two important features that merit its study, i.e., it inhibits polymerization of sickle HbS and its elevated concentration in some thalassemias is a useful clinical diagnostic. However, reports on its functional properties regarding O2 binding are conflicting. We have attempted to resolve these discrepancies by expressing, for the first time, recombinant hemoglobin A2 and systematically studying its functional properties. The construct expressing HbA2 contains only alpha and delta genes so that the extensive purification required to isolate natural HbA2 is circumvented. Although natural hemoglobin A2 is expressed at low levels in vivo, the amount of recombinant alpha2delta2 expressed in yeast is similar to that found for adult hemoglobin A and for fetal hemoglobin F when the alpha + beta or the alpha + gamma genes, respectively, are present on the construct. Recombinant HbA2 is stable, i.e., not easily oxidized, and it is a cooperative functional hemoglobin with tetramer-dimer dissociation properties like those of adult HbA. However, its intrinsic oxygen affinity and response to the allosteric regulators chloride and 2,3-diphosphoglycerate are lower than the corresponding properties for adult hemoglobin. Molecular modeling studies which attempt to understand these properties of HbA2 are described.
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50
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Baudin-Creuza V, Vasseur-Godbillon C, Griffon N, Kister J, Kiger L, Poyart C, Marden MC, Pagnier J. Additive effects of beta chain mutations in low oxygen affinity hemoglobin betaF41Y,K66T. J Biol Chem 1999; 274:25550-4. [PMID: 10464287 DOI: 10.1074/jbc.274.36.25550] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In order to decrease significantly the oxygen affinity of human hemoglobin, we have associated the mutation betaF41Y with another point mutation also known to decrease the oxygen affinity of Hb. We have synthesized a recombinant Hb (rHb) with two mutations in the beta chains: rHb betaF41Y,K66T. In the absence of 2, 3-diphosphoglycerate, additive effects of the mutations are evident, since the doubly mutated Hb exhibits a larger decrease in oxygen affinity than for the individual single mutations. In the presence of 2,3-diphosphoglycerate, the second mutation did not significantly increase the P(50) value relative to the single mutations. However, the kinetics of CO binding still indicate combined effects on the allosteric equilibrium, as evidenced by more of the slow bimolecular phase characteristic of binding to the deoxy conformation. Dimer-tetramer equilibrium studies indicate an increase in stability of the mutants relative to rHb A; the double mutant rHb betaF41Y, K66T at pH 7.5 showed a K(4,2) value of 0.26 microM. Despite the lower oxygen affinity, the single mutant betaF41Y and double mutant betaF41Y,K66T show only a moderate increase of 20% in the autoxidation rate. These mutations are thus of interest in developing a Hb-based blood substitute.
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Affiliation(s)
- V Baudin-Creuza
- INSERM, Unité 473, 84 rue du Général Leclerc, 94276 Le Kremlin-Bicêtre Cedex, France.
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