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The Sickle-Cell Fiber Revisited. Biomolecules 2023; 13:biom13030413. [PMID: 36979347 PMCID: PMC10046210 DOI: 10.3390/biom13030413] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/25/2023] Open
Abstract
Sickle cell disease is the consequence of a single point mutation on the surface of the β chains of the hemoglobin molecule leading to the formation of rigid polymers that disrupt circulation. It has long been established that the polymers are comprised of seven pairs of double strands that are twisted replicas of the double strands found in crystals. Here, we review several newer developments that elaborate on that simple model and provide deeper insights into the process.
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2
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Silverstein TP. The Proton in Biochemistry: Impacts on Bioenergetics, Biophysical Chemistry, and Bioorganic Chemistry. Front Mol Biosci 2021; 8:764099. [PMID: 34901158 PMCID: PMC8661011 DOI: 10.3389/fmolb.2021.764099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
The proton is the smallest atomic particle, and in aqueous solution it is the smallest hydrated ion, having only two waters in its first hydration shell. In this article we survey key aspects of the proton in chemistry and biochemistry, starting with the definitions of pH and pK a and their application inside biological cells. This includes an exploration of pH in nanoscale spaces, distinguishing between bulk and interfacial phases. We survey the Eigen and Zundel models of the structure of the hydrated proton, and how these can be used to explain: a) the behavior of protons at the water-hydrophobic interface, and b) the extraordinarily high mobility of protons in bulk water via Grotthuss hopping, and inside proteins via proton wires. Lastly, we survey key aspects of the effect of proton concentration and proton transfer on biochemical reactions including ligand binding and enzyme catalysis, as well as pH effects on biochemical thermodynamics, including the Chemiosmotic Theory. We find, for example, that the spontaneity of ATP hydrolysis at pH ≥ 7 is not due to any inherent property of ATP (or ADP or phosphate), but rather to the low concentration of H+. Additionally, we show that acidification due to fermentation does not derive from the organic acid waste products, but rather from the proton produced by ATP hydrolysis.
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Affiliation(s)
- Todd P Silverstein
- Chemistry Department (emeritus), Willamette University, Salem, OR, United States
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3
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Abstract
This chapter reviews how allosteric (heterotrophic) effectors and natural mutations impact hemoglobin (Hb) primary physiological function of oxygen binding and transport. First, an introduction about the structure of Hb is provided, including the ensemble of tense and relaxed Hb states and the dynamic equilibrium of Hb multistate. This is followed by a brief review of Hb variants with altered Hb structure and oxygen binding properties. Finally, a review of different endogenous and exogenous allosteric effectors of Hb is presented with particular emphasis on the atomic interactions of synthetic ligands with altered allosteric function of Hb that could potentially be harnessed for the treatment of diseases.
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Affiliation(s)
- Mostafa H Ahmed
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23219, USA
| | - Mohini S Ghatge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23219, USA.,Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, 23219, USA
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23219, USA. .,Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, 23219, USA.
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4
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Okonjo KO. Bohr effect and oxygen affinity of carp, eel and human hemoglobin: Quantitative analyses provide rationale for the Root effect. Biophys Chem 2018; 242:45-59. [PMID: 30245351 DOI: 10.1016/j.bpc.2018.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/07/2018] [Accepted: 09/07/2018] [Indexed: 11/29/2022]
Abstract
The functional properties of most fish hemoglobins are more complex than those of human hemoglobin. This complexity arises in the form of the Root effect, in which the oxygen affinity of such fish hemoglobins decreases rapidly with pH relative to that of human hemoglobin. Cooperative ligand binding is also diminished below pH ≈ 6.5. The Bohr effect, determined by acid-base titration, has been reported for the Root effect carp and anodic eel hemoglobins. Unlike for mammalian hemoglobins, the Wyman equation for the Bohr effect fails to account quantitatively for these Bohr data. We present a successful quantitative accounting for these data based on evidence for multiple T states in various fish hemoglobins and on their lack of sixhistidine Bohr groups, with pKoxy > pKdeoxy. On the same bases we also provide a rationale for the higher pH sensitivity of the oxygen affinity of carp compared to human hemoglobin.
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Schay G, Kaposi AD, Smeller L, Szigeti K, Fidy J, Herenyi L. Dissimilar flexibility of α and β subunits of human adult hemoglobin influences the protein dynamics and its alteration induced by allosteric effectors. PLoS One 2018; 13:e0194994. [PMID: 29584765 PMCID: PMC5871000 DOI: 10.1371/journal.pone.0194994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/14/2018] [Indexed: 12/19/2022] Open
Abstract
The general question by what mechanism an "effector" molecule and the hemes of hemoglobin interact over widely separated intramolecular distances to change the oxygen affinity has been extensively investigated, and still has remained of central interest. In the present work we were interested in clarifying the general role of the protein matrix and its dynamics in the regulation of human adult hemoglobin (HbA). We used a spectroscopy approach that yields the compressibility (κ) of the protein matrix around the hemes of the subunits in HbA and studied how the binding of heterotropic allosteric effectors modify this parameter. κ is directly related to the variance of volume fluctuation, therefore it characterizes the molecular dynamics of the protein structure. For the experiments the heme groups either in the α or in the β subunits of HbA were replaced by fluorescent Zn-protoporphyrinIX, and series of fluorescence line narrowed spectra were measured at varied pressures. The evaluation of the spectra yielded the compressibility that showed significant dynamic asymmetry between the subunits: κ of the α subunit was 0.17±0.05/GPa, while for the β subunit it was much higher, 0.36±0.07/GPa. The heterotropic effectors, chloride ions, inositol hexaphosphate and bezafibrate did not cause significant changes in κ of the α subunits, while in the β subunits the effectors lead to a significant reduction down to 0.15±0.04/GPa. We relate our results to structural data, to results of recent functional studies and to those of molecular dynamics simulations, and find good agreements. The observed asymmetry in the flexibility suggests a distinct role of the subunits in the regulation of Hb that results in the observed changes of the oxygen binding capability.
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Affiliation(s)
- Gusztáv Schay
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - András D. Kaposi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - László Smeller
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Judit Fidy
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Levente Herenyi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
- * E-mail:
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6
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Okonjo KO. Bohr effect of human hemoglobin: Separation of tertiary and quaternary contributions based on the Wyman equation. Biophys Chem 2017; 228:87-97. [PMID: 28743047 DOI: 10.1016/j.bpc.2017.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 07/12/2017] [Indexed: 11/19/2022]
Abstract
As a prelude to separating tertiary from quaternary structure contributions to the Bohr effect, we employed the Wyman equation to analyze Bohr data for human hemoglobin to which 2,3-bisphosphoglycerate, 2,3-BPG, is bound. Changes in the pKas of the histidine Bohr groups result in a net reduction of their contributions to the Bohr effect at pH 7.4 compared to their contributions in stripped hemoglobin. The non-histidine 2,3-BPG binding groups - the β-chain terminal amino group and Lys82β - make negative and positive contributions, respectively, to the Bohr effect. The final result is that the Bohr effect at physiological pH is higher for 2,3-BPG bound compared to stripped hemoglobin. Contributions linked to His2β, His77β and His143β enable us to separate tertiary from quaternary Bohr contributions in stripped and in 2,3-BPG bound hemoglobin. Both contributions serve to make the Bohr effect for 2,3-BPG bound hemoglobin higher than for stripped hemoglobin at physiological pH.
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7
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Okonjo KO. Bohr effect of native and chemically modified hemoglobins: Quantitative analyses based on the Wyman equation. Biophys Chem 2017; 226:34-42. [DOI: 10.1016/j.bpc.2017.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/21/2017] [Accepted: 04/13/2017] [Indexed: 11/25/2022]
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8
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Okonjo KO. Bohr effect of avian hemoglobins: Quantitative analyses based on the Wyman equation. J Theor Biol 2016; 410:25-35. [DOI: 10.1016/j.jtbi.2016.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 08/01/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
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9
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Dajnowicz S, Seaver S, Hanson BL, Fisher SZ, Langan P, Kovalevsky AY, Mueser TC. Visualizing the Bohr effect in hemoglobin: neutron structure of equine cyanomethemoglobin in the R state and comparison with human deoxyhemoglobin in the T state. Acta Crystallogr D Struct Biol 2016; 72:892-903. [PMID: 27377386 PMCID: PMC4932920 DOI: 10.1107/s2059798316009049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 06/03/2016] [Indexed: 11/17/2022] Open
Abstract
Neutron crystallography provides direct visual evidence of the atomic positions of deuterium-exchanged H atoms, enabling the accurate determination of the protonation/deuteration state of hydrated biomolecules. Comparison of two neutron structures of hemoglobins, human deoxyhemoglobin (T state) and equine cyanomethemoglobin (R state), offers a direct observation of histidine residues that are likely to contribute to the Bohr effect. Previous studies have shown that the T-state N-terminal and C-terminal salt bridges appear to have a partial instead of a primary overall contribution. Four conserved histidine residues [αHis72(EF1), αHis103(G10), αHis89(FG1), αHis112(G19) and βHis97(FG4)] can become protonated/deuterated from the R to the T state, while two histidine residues [αHis20(B1) and βHis117(G19)] can lose a proton/deuteron. αHis103(G10), located in the α1:β1 dimer interface, appears to be a Bohr group that undergoes structural changes: in the R state it is singly protonated/deuterated and hydrogen-bonded through a water network to βAsn108(G10) and in the T state it is doubly protonated/deuterated with the network uncoupled. The very long-term H/D exchange of the amide protons identifies regions that are accessible to exchange as well as regions that are impermeable to exchange. The liganded relaxed state (R state) has comparable levels of exchange (17.1% non-exchanged) compared with the deoxy tense state (T state; 11.8% non-exchanged). Interestingly, the regions of non-exchanged protons shift from the tetramer interfaces in the T-state interface (α1:β2 and α2:β1) to the cores of the individual monomers and to the dimer interfaces (α1:β1 and α2:β2) in the R state. The comparison of regions of stability in the two states allows a visualization of the conservation of fold energy necessary for ligand binding and release.
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Affiliation(s)
- Steven Dajnowicz
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - Sean Seaver
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - B. Leif Hanson
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - S. Zoë Fisher
- Scientific Activities Division, Science Directorate, European Spallation Source, PO Box 176, 221 00 Lund, Sweden
| | - Paul Langan
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Andrey Y. Kovalevsky
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Timothy C. Mueser
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
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10
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Bohr effect of hemoglobins: Accounting for differences in magnitude. J Theor Biol 2015; 380:436-43. [DOI: 10.1016/j.jtbi.2015.06.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/08/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022]
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Affiliation(s)
- Yue Yuan
- Department of Biological Sciences Carnegie Mellon University Pittsburgh, PA 15213
| | - Ming F. Tam
- Department of Biological Sciences Carnegie Mellon University Pittsburgh, PA 15213
| | - Virgil Simplaceanu
- Department of Biological Sciences Carnegie Mellon University Pittsburgh, PA 15213
| | - Chien Ho
- Department of Biological Sciences Carnegie Mellon University Pittsburgh, PA 15213
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12
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Okonjo KO, Olatunde AM, Fodeke AA, Babalola JO. Bohr effect of human hemoglobin A: Magnitude of negative contributions determined by the equilibrium between two tertiary structures. Biophys Chem 2014; 190-191:41-9. [DOI: 10.1016/j.bpc.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/04/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
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13
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Noguchi H, Campbell KL, Ho C, Unzai S, Park SY, Tame JRH. Structures of haemoglobin from woolly mammoth in liganded and unliganded states. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1441-9. [PMID: 23090393 DOI: 10.1107/s0907444912029459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/28/2012] [Indexed: 11/11/2022]
Abstract
The haemoglobin (Hb) of the extinct woolly mammoth has been recreated using recombinant genes expressed in Escherichia coli. The globin gene sequences were previously determined using DNA recovered from frozen cadavers. Although highly similar to the Hb of existing elephants, the woolly mammoth protein shows rather different responses to chloride ions and temperature. In particular, the heat of oxygenation is found to be much lower in mammoth Hb, which appears to be an adaptation to the harsh high-latitude climates of the Pleistocene Ice Ages and has been linked to heightened sensitivity of the mammoth protein to protons, chloride ions and organic phosphates relative to that of Asian elephants. To elucidate the structural basis for the altered homotropic and heterotropic effects, the crystal structures of mammoth Hb have been determined in the deoxy, carbonmonoxy and aquo-met forms. These models, which are the first structures of Hb from an extinct species, show many features reminiscent of human Hb, but underline how the delicate control of oxygen affinity relies on much more than simple overall quaternary-structure changes.
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Affiliation(s)
- Hiroki Noguchi
- Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Yokohama 230-0045, Japan
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14
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Yuan Y, Shen TJ, Gupta P, Ho NT, Simplaceanu V, Tam TCS, Hofreiter M, Cooper A, Campbell KL, Ho C. A biochemical--biophysical study of hemoglobins from woolly mammoth, Asian elephant, and humans. Biochemistry 2011; 50:7350-60. [PMID: 21806075 DOI: 10.1021/bi200777j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study is aimed at investigating the molecular basis of environmental adaptation of woolly mammoth hemoglobin (Hb) to the harsh thermal conditions of the Pleistocene ice ages. To this end, we have carried out a comparative biochemical-biophysical characterization of the structural and functional properties of recombinant hemoglobins (rHb) from woolly mammoth (rHb WM) and Asian elephant (rHb AE) in relation to human hemoglobins Hb A and Hb A(2) (a minor component of human blood). We have obtained oxygen equilibrium curves and calculated O(2) affinities, Bohr effects, and the apparent heat of oxygenation (ΔH) in the presence and absence of allosteric effectors [inorganic phosphate and inositol hexaphosphate (IHP)]. Here, we show that the four Hbs exhibit distinct structural properties and respond differently to allosteric effectors. In addition, the apparent heat of oxygenation (ΔH) for rHb WM is less negative than that of rHb AE, especially in phosphate buffer and the presence of IHP, suggesting that the oxygen affinity of mammoth blood was also less sensitive to temperature change. Finally, (1)H NMR spectroscopy data indicates that both α(1)(β/δ)(1) and α(1)(β/δ)(2) interfaces in rHb WM and rHb AE are perturbed, whereas only the α(1)δ(1) interface in Hb A(2) is perturbed compared to that in Hb A. The distinct structural and functional features of rHb WM presumably facilitated woolly mammoth survival in the Arctic environment.
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Affiliation(s)
- Yue Yuan
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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15
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Safo MK, Ahmed MH, Ghatge MS, Boyiri T. Hemoglobin-ligand binding: understanding Hb function and allostery on atomic level. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:797-809. [PMID: 21396487 DOI: 10.1016/j.bbapap.2011.02.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 10/18/2022]
Abstract
The major physiological function of hemoglobin (Hb) is to bind oxygen in the lungs and deliver it to the tissues. This function is regulated and/or made efficient by endogenous heterotropic effectors. A number of synthetic molecules also bind to Hb to alter its allosteric activity. Our purpose is to review the current state of Hb structure and function that involves ensemble of tense and relaxed hemoglobin states and the dynamic equilibrium of the multistate due to the binding of endogenous heterotropic or synthetic allosteric effectors. The review also discusses the atomic interactions of synthetic ligands with the function or altered allosteric function of Hb that could be potentially harnessed for the treatment of diseases. This article is part of a Special Issue entitled: Protein Structure and Function in the Crystalline State.
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Affiliation(s)
- Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23219, USA.
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Kovalevsky A, Chatake T, Shibayama N, Park SY, Ishikawa T, Mustyakimov M, Fisher SZ, Langan P, Morimoto Y. Protonation states of histidine and other key residues in deoxy normal human adult hemoglobin by neutron protein crystallography. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:1144-52. [PMID: 21041929 PMCID: PMC2967419 DOI: 10.1107/s0907444910025448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 06/28/2010] [Indexed: 11/10/2022]
Abstract
The protonation states of the histidine residues key to the function of deoxy (T-state) human hemoglobin have been investigated using neutron protein crystallography. These residues can reversibly bind protons, thereby regulating the oxygen affinity of hemoglobin. By examining the OMIT F(o)-F(c) and 2F(o)-F(c) neutron scattering maps, the protonation states of 35 of the 38 His residues were directly determined. The remaining three residues were found to be disordered. Surprisingly, seven pairs of His residues from equivalent α or β chains, αHis20, αHis50, αHis58, αHis89, βHis63, βHis143 and βHis146, have different protonation states. The protonation of distal His residues in the α(1)β(1) heterodimer and the protonation of αHis103 in both subunits demonstrates that these residues may participate in buffering hydrogen ions and may influence the oxygen binding. The observed protonation states of His residues are compared with their ΔpK(a) between the deoxy and oxy states. Examination of inter-subunit interfaces provided evidence for interactions that are essential for the stability of the deoxy tertiary structure.
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Affiliation(s)
- Andrey Kovalevsky
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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Kovalevsky AY, Chatake T, Shibayama N, Park SY, Ishikawa T, Mustyakimov M, Fisher Z, Langan P, Morimoto Y. Direct determination of protonation states of histidine residues in a 2 A neutron structure of deoxy-human normal adult hemoglobin and implications for the Bohr effect. J Mol Biol 2010; 398:276-91. [PMID: 20230836 DOI: 10.1016/j.jmb.2010.03.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 03/06/2010] [Accepted: 03/09/2010] [Indexed: 11/26/2022]
Abstract
We have investigated the protonation states of histidine residues (potential Bohr groups) in the deoxy form (T state) of human hemoglobin by direct determination of hydrogen (deuterium) positions with the neutron protein crystallography technique. The reversible binding of protons is key to the allosteric regulation of human hemoglobin. The protonation states of 35 of the 38 His residues were directly determined from neutron scattering omit maps, with 3 of the remaining residues being disordered. Protonation states of 5 equivalent His residues--alpha His20, alpha His50, alpha His89, beta His143, and beta His146--differ between the symmetry-related globin subunits. The distal His residues, alpha His58 and beta His63, are protonated in the alpha 1 beta 1 heterodimer and are neutral in alpha 2 beta 2. Buried residue alpha His103 is found to be protonated in both subunits. These distal and buried residues have the potential to act as Bohr groups. The observed protonation states of His residues are compared to changes in their pK(a) values during the transition from the T to the R state and the results provide some new insights into our understanding of the molecular mechanism of the Bohr effect.
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Affiliation(s)
- Andrey Y Kovalevsky
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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Soller BR, Yang Y, Lee SMC, Wilson C, Hagan RD. Noninvasive determination of exercise-induced hydrodgen ion threshold through direct optical measurement. J Appl Physiol (1985) 2008; 104:837-44. [DOI: 10.1152/japplphysiol.00849.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The intensity of exercise above which oxygen uptake (V̇o2) does not account for all of the required energy to perform work has been associated with lactate accumulation in the blood (lactate threshold, LT) and elevated carbon dioxide output (gas exchange threshold). An increase in hydrogen ion concentration ([H+]) is approximately concurrent with elevation of blood lactate and CO2 output during exercise. Near-infrared spectra (NIRS) and invasive interstitial fluid pH (pHm) were measured in the flexor digitorum profundus during handgrip exercise to produce a mathematical model relating the two measures with an estimated error of 0.035 pH units. This NIRS pHm model was subsequently applied to spectra collected from the vastus lateralis of 10 subjects performing an incremental-intensity cycle protocol. Muscle oxygen saturation (SmO2) was also calculated from spectra. We hypothesized that a H+ threshold could be identified for these subjects and that it would be different from but correlated with the LT. Lactate, gas exchange, SmO2, and H+ thresholds were determined as a function of V̇o2 using bilinear regression. LT was significantly different from both the gas exchange threshold (Δ = 0.27 ± 0.29 l/min) and H+ threshold (Δ = 0.29 ± 0.23 l/min), but the gas exchange threshold was not significantly different from the H+ threshold (Δ = 0.00 ± 0.38 l/min). The H+ threshold was strongly correlated with LT ( R2 = 0.95) and the gas exchange threshold ( R2 = 0.85). This initial study demonstrates the feasibility of noninvasive pHm estimations, the determination of H+ threshold, and the relationship between H+ and classical metabolic thresholds during incremental exercise.
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Rezaei-Zarchi S, Saboury AA, Norouzi P, Hong J, Ahmadian S, Ganjali MR, Moosavi-Movahedi AA, Moghaddam AB, Javed A. Use of silver nanoparticles as an electron transfer facilitator in electrochemical ligand-binding of haemoglobin. J APPL ELECTROCHEM 2007. [DOI: 10.1007/s10800-007-9343-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Rezaei-Zarchi S, Saboury AA, Ghourchian H, Hong J, Barzegar A, Norouzi P, Moosavi-Movahedi AA, Ganjali MR, Javed A. Electrochemical investigation of the effect of some organic phosphates on haemoglobin. J Biosci 2007; 32:271-8. [PMID: 17435319 DOI: 10.1007/s12038-007-0027-y] [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: 11/26/2022]
Abstract
The effects of DPG,IHP,GTP,GDP and GMP on the structure and stability of haemoglobin were electrochemically investigated with an iodide-modified silver electrode in 0.01 M KNO 3 at pH 7.0.Anodic and cathodic peaks of haemoglobin were observed at 250 mV and 12 mV with a formal potential value of 133 mV vs.Ag/AgCl.The effects of different concentrations of DPG,IHP,GTP,GDP and GMP on the anaerobic redox reaction were determined. The results showed that DPG and IHP can lead to a positive shift in the reduction peak of haemoglobin,indicating that the oxidation peak shift of haemoglobin was small as a result of stabilization of the reduced state and destabilization of the R-like state of haemoglobin.GTP elicited a more positive shift in the cathodic and anodic peaks of haemoglobin at a higher concentration,signifying that it has a low-affinity binding site on haemoglobin.The positive shift of the cathodic and anodic peaks revealed a slight variation in the structure and indicated the unfolding of haemoglobin in the presence of high concentrations of GTP.Our study also showed that GDP and GMP did not cause significant shift the cathodic and anodic peaks of haemoglobin even at high concentrations,refuting the existence of specific GDP-and GMP-binding sites on the protein.Moreover,the iodide-modified silver electrode method proved to be easy and useful in investigating the effects of ligands or other effectors on haemoglobin in solution.
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Affiliation(s)
- S Rezaei-Zarchi
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
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Ceccarelli M, Ruggerone P, Anedda R, Fais A, Era B, Sollaino MC, Corda M, Casu M. Structure-function relationship in a variant hemoglobin: a combined computational-experimental approach. Biophys J 2006; 91:3529-41. [PMID: 16844744 PMCID: PMC1614504 DOI: 10.1529/biophysj.106.083170] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2006] [Accepted: 05/19/2006] [Indexed: 11/18/2022] Open
Abstract
Our study examines the functional and structural effects of amino acid substitution in the distal side of beta-chains of human Hb Duarte (alpha(2)beta(2)(62Ala-->Pro)). We have compared the functional properties of the purified Hb Duarte with those of HbA, and through proton NMR and molecular dynamics simulations we have investigated their tertiary and quaternary structures. The variant exhibits an increased oxygen affinity with a normal Hill coefficient and Bohr effect. The abnormal function of Hb Duarte is attributed to the presence of a proline residue at the beta62 position, since the functional properties of another Hb variant in the same position, Hb J-Europa (beta(62Ala-->Asp)), have been described as normal. Thereafter (1)H-NMR studies have shown that the beta62 Ala-->Pro substitution causes structural modifications of the tertiary structure of the beta globins, leaving the quaternary structure unaltered. These results have been confirmed by extensive all-atom molecular dynamics simulations. All these findings lead to the conclusion that the beta62 Ala-->Pro substitution produces a destabilization of the E-helix extending downward to the CD corner. Particularly, a cavity near the distal histidine of the beta-chains, connecting the heme pocket to the solvent, is affected, altering the functional properties of the protein molecule.
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Affiliation(s)
- Matteo Ceccarelli
- CNR-INFM SLACS, Dipartimento di Fisica, Università di Cagliari, I-09042 Monserrato, Italy
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22
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Eaton WA, Henry ER, Hofrichter J, Mozzarelli A. Is cooperative oxygen binding by hemoglobin really understood? ACTA ACUST UNITED AC 2006. [DOI: 10.1007/bf02904506] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Berenbrink M. Evolution of vertebrate haemoglobins: Histidine side chains, specific buffer value and Bohr effect. Respir Physiol Neurobiol 2006; 154:165-84. [PMID: 16481225 DOI: 10.1016/j.resp.2006.01.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 01/04/2006] [Accepted: 01/05/2006] [Indexed: 11/23/2022]
Abstract
This review highlights the use of analytical tools, recently developed in the comparative method of evolutionary biology, for the study of haemoglobin (Hb) adaptation. It focuses on the functional consequences of a previously largely ignored structural feature of Hb, namely the degree and positional specificity of histidine (His) substitution in Hb chains. The importance of His side chains for hydrogen ion buffering, blood CO(2) transport capacity and the molecular mechanism of the Bohr effect in vertebrate Hbs is discussed. Using phylogenetically independent contrasts, a significant correlation between the specific buffer value of Hb and the number of predicted physiological buffer groups from Hb sequence data is shown. In a new result, the evolution of the number of physiological buffer groups in 77 vertebrate species is reconstructed on a phylogenetic tree. The analysis predicts that teleost fishes, passeriform birds and some snakes have independently evolved a much-reduced specific buffer value of Hb, possibly for enhancing the efficiency of an acid load to change oxygen affinity via the Bohr effect. This analysis demonstrates how in comparative physiology analysis of genetic databases in an evolutionary framework can identify candidate species for further experimental in vitro and whole animal studies.
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Affiliation(s)
- Michael Berenbrink
- School of Biological Sciences, The University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK.
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24
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Abstract
All vertebrate embryos produce a specific erythroid cell population--primitive erythrocytes--early in development. These cells are characterized by expression of the specific embryonic haemoglobins. Many aspects of primitive erythropoiesis and the physiological function of primitive red cells are still enigmatic. Nevertheless, recent years have seen intensive efforts to characterize in greater detail the molecular events underlying the initiation of erythropoiesis in vertebrate embryos. Several key genes have been identified that are necessary for primitive and the subsequent definitive erythropoiesis, which differs in several aspect from primitive erythropoiesis. This review gives in its first part a short overview dealing with comparative aspects of primitive and early definitive erythropoiesis in higher and lower vertebrates and in the second part we discuss the physiological function of primitive red cells based mainly on results from mammalian and avian embryos.
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Affiliation(s)
- R Baumann
- Physiologisches Institut, University of Regensburg, Germany.
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25
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Sun Y, Liu X, Fan C, Zhang W, Li G. Electrochemical investigation of the chloride effect on hemoglobin. Bioelectrochemistry 2004; 64:23-7. [PMID: 15219242 DOI: 10.1016/j.bioelechem.2004.01.003] [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] [Received: 04/21/2003] [Revised: 01/05/2004] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
Direct electron transfer between hemoglobin and gold electrode is achieved at both a bare and a 4, 4'-bipyridine-modified gold electrode in the presence of chloride ions. The addition of chloride to hemoglobin solution also increases the reversibility of the direct electrochemistry and shifts the formal potential of hemoglobin to the negative direction. While the existence of chloride does not significantly change the tertiary structure of the protein, it might induce a slight variation of the structure, which is beneficial to the electrochemical response. It is suggested that the chloride binding to hemoglobin is a combination of specific and unspecific bindings.
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Affiliation(s)
- Yuting Sun
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China
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26
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Barrick D, Lukin JA, Simplaceanu V, Ho C. Nuclear magnetic resonance spectroscopy in the study of hemoglobin cooperativity. Methods Enzymol 2004; 379:28-54. [PMID: 15051350 DOI: 10.1016/s0076-6879(04)79002-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Doug Barrick
- Department of Biophysics, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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27
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Lukin JA, Ho C. The Structure−Function Relationship of Hemoglobin in Solution at Atomic Resolution. Chem Rev 2004; 104:1219-30. [PMID: 15008621 DOI: 10.1021/cr940325w] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jonathan A Lukin
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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28
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Tsai CH, Simplaceanu V, Ho NT, Shen TJ, Wang D, Spiro TG, Ho C. Site mutations disrupt inter-helical H-bonds (alpha14W-alpha67T and beta15W-beta72S) involved in kinetic steps in the hemoglobin R-->T transition without altering the free energies of oxygenation. Biophys Chem 2003; 100:131-42. [PMID: 12646359 DOI: 10.1016/s0301-4622(02)00274-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Three recombinant mutant hemoglobins (rHbs) of human normal adult hemoglobin (Hb A), rHb (alphaT67V), rHb (betaS72A), and rHb (alphaT67V, betaS72A), have been constructed to test the role of the tertiary intra-subunit H-bonds between alpha67T and alpha14W and between beta72S and beta15W in the cooperative oxygenation of Hb A. Oxygen-binding studies in 0.1 M sodium phosphate buffer at 29 degrees C show that rHb (alphaT67V), rHb (betaS72A), and rHb (alphaT67V, betaS72A) exhibit oxygen-binding properties similar to those of Hb A. The binding of oxygen to these rHbs is highly cooperative, with a Hill coefficient of approximately 2.8, compared to approximately 3.1 for Hb A. Proton nuclear magnetic resonance (NMR) studies show that rHb (alphaT67V), rHb (betaS72A), rHb (alphaT67V, betaS72A), and Hb A have similar quaternary structures in the alpha(1)beta(2) subunit interfaces. In particular, the inter-subunit H-bonds between alpha42Tyr and beta99Asp and between beta37Trp and alpha94Asp are maintained in the mutants in the deoxy form. There are slight perturbations in the distal heme pocket region of the alpha- and beta-chains in the mutants. A comparison of the exchangeable 1H resonances of Hb A with those of these three rHbs suggests that alpha67T and beta72S are H-bonded to alpha14W and beta15W, respectively, in the CO and deoxy forms of Hb A. The absence of significant free energy changes for the oxygenation process of these three rHbs compared to those of Hb A, even though the inter-helical H-bonds are abolished, indicates that these two sets of H-bonds are of comparable strength in the ligated and unligated forms of Hb A. Thus, the mutations at alphaT67V and betaS72A do not affect the overall energetics of the oxygenation process. The preserved cooperativity in the binding of oxygen to these three mutants also implies that there are multiple interactions involved in the oxygenation process of Hb A.
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Affiliation(s)
- Ching-Hsuan Tsai
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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29
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Pomponi M, Bertonati C, Patamia M, Marta M, Derocher AE, Lydersen C, Kovacs KM, Wiig O, Bårdgard AJ. Polar bear hemoglobin and human Hb A0: same 2,3-diphosphoglycerate binding site but asymmetry of the binding? Hemoglobin 2002; 26:363-71. [PMID: 12484631 DOI: 10.1081/hem-120016373] [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
Polar bear (Ursus maritimus) hemoglobin (Hb) shows a low response to 2,3-diphosphoglycerate (2,3-DPG), compared to human Hb A0, even though these proteins have the same 2,3-DPG-binding site. In addition, polar bear Hb shows a high response to chloride and an alkaline Bohr effect (deltalog P50/deltapH) that is significantly greater than that of human Hb A0. The difference in sequence Pro (Hb A0)-->Gly (polar bear Hb) at position A2 in the A helix seems to be critical for reduced binding of 2,3-DPG. Our results also show that the A2 position may influence not only the flexibility of the A helix, but that differences in flexibility of the first turn of the A helix may affect the unloading of oxygen for the intrinsic ligand affinities of the alpha and beta chains. However, preferential binding to either chain can only take place if there is appreciable asymmetric binding of the phosphoric effector. Regarding this point, 31P NMR data suggest a loss of symmetry of the 2,3-DPG-binding site in the deoxyHb-2,3-DPG complex.
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Affiliation(s)
- Massimo Pomponi
- Istituto di Biochimica, Università Cattolica Sacro Cuore, Facoltà di Medicina A. Gemelli Largo F. Vito 1, 00168 Roma, Italia.
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30
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Abstract
By introducing an additional H-bond in the alpha(1)beta(2) subunit interface or altering the charge properties of the amino acid residues in the alpha(1)beta(1) subunit interface of the hemoglobin molecule, we have designed and expressed recombinant hemoglobins (rHbs) with low oxygen affinity and high cooperativity. Oxygen-binding measurements of these rHbs under various experimental conditions show interesting properties in response to pH (Bohr effect) and allosteric effectors. Proton nuclear magnetic resonance studies show that these rHbs can switch from the oxy (or CO) quaternary structure (R) to the deoxy quaternary structure (T) without changing their ligation states upon addition of an allosteric effector, inositol hexaphosphate, and/or reduction of the ambient temperature. These results indicate that if we can provide extra stability to the T state of the hemoglobin molecule without perturbing its R state, we can produce hemoglobins with low oxygen affinity and high cooperativity. Some of these rHbs are also quite stable against autoxidation compared to many of the known abnormal hemoglobins with altered oxygen affinity and cooperativity. These results have provided new insights into the structure-function relationship in hemoglobin.
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Affiliation(s)
- Ching-Hsuan Tsai
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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31
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Noble RW, Kwiatkowski LD, Hui HL, Bruno S, Bettati S, Mozzarelli A. Correlation of protein functional properties in the crystal and in solution: the case study of T-state hemoglobin. Protein Sci 2002; 11:1845-9. [PMID: 12070336 PMCID: PMC2373653 DOI: 10.1110/ps.0205702] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The relevance of three-dimensional structures of proteins, determined by X-ray crystallography, is an important issue that is becoming even more critical in light of the Structural Genomics Initiative. As a case study, a detailed comparison of functional properties of the T quaternary states of genetically or chemically modified human hemoglobins (Hbs) in solution and in the crystal was performed. Oxygen affinities of Hbs in crystals correlate with the rate constants of their initial combination with carbon monoxide (CO) in solution, indicating that changes in ligand affinity caused by the modifications are similarly observed in both physical states.
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Affiliation(s)
- Robert W Noble
- Department of Medicine, State University of New York (SUNY) at Buffalo, Veterans Administration Medical Center, 3495 Bailey Avenue, Buffalo, NY 14215, USA.
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32
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Simplaceanu V, Lukin JA, Fang TY, Zou M, Ho NT, Ho C. Chain-selective isotopic labeling for NMR studies of large multimeric proteins: application to hemoglobin. Biophys J 2000; 79:1146-54. [PMID: 10920044 PMCID: PMC1301010 DOI: 10.1016/s0006-3495(00)76368-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Multidimensional, multinuclear NMR has the potential to elucidate the mechanisms of allostery and cooperativity in multimeric proteins under near-physiological conditions. However, NMR studies of proteins made up of non-equivalent subunits face the problem of severe resonance overlap, which can prevent the unambiguous assignment of resonances, a necessary step in interpreting the spectra. We report the application of a chain-selective labeling technique, in which one type of subunit is labeled at a time, to carbonmonoxy-hemoglobin A (HbCO A). This labeling method can be used to extend previous resonance assignments of key amino acid residues, which are important to the physiological function of hemoglobin. Among these amino acid residues are the surface histidyls, which account for the majority of the Bohr effect. In the present work, we report the results of two-dimensional heteronuclear multiple quantum coherence (HMQC) experiments performed on recombinant (15)N-labeled HbCO A. In addition to the C2-proton (H epsilon(1)) chemical shifts, these spectra also reveal the corresponding C4-proton (H delta(2)) resonances, correlated with the N epsilon(2) and N delta(1) chemical shifts of all 13 surface histidines per alpha beta dimer. The HMQC spectrum also allows the assignment of the H delta(1), H epsilon(1), and N epsilon(1) resonances of all three tryptophan residues per alpha beta dimer in HbCO A. These results indicate that heteronuclear NMR, used with chain-selective isotopic labeling, can provide resonance assignments of key regions in large, multimeric proteins, suggesting an approach to elucidating the solution structure of hemoglobin, a protein with molecular weight 64.5 kDa.
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Affiliation(s)
- V Simplaceanu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 USA
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33
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Bruno S, Bettati S, Manfredini M, Mozzarelli A, Bolognesi M, Deriu D, Rosano C, Tsuneshige A, Yonetani T, Henry ER. Oxygen binding by alpha(Fe2+)2beta(Ni2+)2 hemoglobin crystals. Protein Sci 2000; 9:683-92. [PMID: 10794410 PMCID: PMC2144622 DOI: 10.1110/ps.9.4.683] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately. Previous studies have characterized the oxygen binding by alpha(Ni2+)2beta(Fe2+)2 crystals. Here, we have determined the three-dimensional (3D) structure and oxygen binding of alpha(Fe2+)2beta(Ni2+)2 crystals grown from polyethylene glycol solutions. Polarized absorption spectra were recorded at different oxygen pressures with light polarized parallel either to the b or c crystal axis by single crystal microspectrophotometry. The oxygen pressures at 50% saturation (p50s) are 95 +/- 3 and 87 +/- 4 Torr along the b and c crystal axes, respectively, and the corresponding Hill coefficients are 0.96 +/- 0.06 and 0.90 +/- 0.03. Analysis of the binding curves, taking into account the different projections of the alpha hemes along the optical directions, indicates that the oxygen affinity of alpha1 hemes is 1.3-fold lower than alpha2 hemes. Inspection of the 3D structure suggests that this inequivalence may arise from packing interactions of the Hb tetramer within the monoclinic crystal lattice. A similar inequivalence was found for the beta subunits of alpha(Ni2+)2beta(Fe2+)2 crystals. The average oxygen affinity of the alpha subunits (p50 = 91 Torr) is about 1.2-fold higher than the beta subunits (p50 = 110 Torr). In the absence of cooperativity, this heterogeneity yields an oxygen binding curve of Hb A with a Hill coefficient of 0.999. Since the binding curves of Hb A crystals exhibit a Hill coefficient very close to unity, these findings indicate that oxygen binding by T-state hemoglobin is noncooperative, in keeping with the Monod, Wyman, and Changeux model.
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Affiliation(s)
- S Bruno
- Institute of Biochemical Sciences, University of Parma, Italy
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34
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Srinivasulu S, Malavalli A, Prabhakaran M, Nagel RL, Acharya AS. Inhibition of beta(S)-chain dependent polymerization by synergistic complementation of contact site perturbations of alpha-chain: application of semisynthetic chimeric alpha-chains. PROTEIN ENGINEERING 1999; 12:1105-11. [PMID: 10611404 DOI: 10.1093/protein/12.12.1105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mouse alpha(1-30)-horse alpha(31-141) chimeric alpha-chain, a semisynthetic super-inhibitory alpha-chain, inhibits beta(S)-chain dependent polymerization better than both parent alpha-chains. Although contact site sequence differences are absent in the alpha(1-30) region of the chimeric chain, the four sequence differences of the region alpha(17-22) could induce perturbations of the side chains at alpha(16), alpha(20) and alpha(23), the three contact sites of the region. A synergistic complementation of such contact site perturbation with that of horse alpha(31-141) probably results in the super-inhibitory activity of the chimeric alpha-chain. The inhibitory contact site sequence differences, by themselves, could also exhibit similar synergistic complementation. Accordingly, the polymerization inhibitory activity of Hb Le-Lamentin (LM) mutation [His20(alpha)-->Gln], a contact site sequence difference, engineered into human-horse chimeric alpha-chain has been investigated to map such a synergistic complementation. Gln20(alpha) has little effect on the O(2) affinity of HbS, but in human-horse chimeric alpha-chain it reduces the O(2) affinity slightly. In the chimeric alpha-chain, Gln20(alpha) increased sensitivity of the betabeta cleft for the DPG influence, reflecting a cross-talk between the alpha(1)beta(1) interface and betabeta cleft in this semisynthetic chimeric HbS. In the human alpha-chain frame, the polymerization inhibitory activity of Gln20(alpha) is higher compared with horse alpha(1-30), but lower than mouse alpha(1-30). Gln20(alpha) synergistically complements the inhibitory propensity of horse alpha(31-141). However, the inhibitory activity of LM-horse chimeric alpha-chain is still lower than that of mouse-horse chimeric alpha-chain. Therefore, perturbation of multiple contact sites in the alpha(1-30) region of the mouse-horse chimeric alpha-chain and its linkage with the inhibitory propensity of horse alpha(31-141) has been now invoked to explain the super-inhibitory activity of the chimeric alpha-chain. The 'linkage-map' of contact sites can serve as a blueprint for designing synergistic complementation of multiple contact sites into alpha-chains as a strategy for generating super-inhibitory antisickling hemoglobins for gene therapy of sickle cell disease.
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Affiliation(s)
- S Srinivasulu
- Division of Hematology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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35
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Wang D, Zhao X, Shen TJ, Ho C, Spiro TG. Role of Interhelical H-Bonds (Wα14−Tα67 and Wβ15−Sβ72) in the Hemoglobin Allosteric Reaction Path Evaluated by UV Resonance Raman Spectroscopy of Site-Mutants. J Am Chem Soc 1999. [DOI: 10.1021/ja992228w] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daojing Wang
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Xiaojie Zhao
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Tong-Jian Shen
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Chien Ho
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Thomas G. Spiro
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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36
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Loupiac C, Kruk N, Valat P, Alpert B. Protein relaxation without a geminate phase in nanosecond photodissociated CO carp hemoglobin. Chem Phys Lett 1999. [DOI: 10.1016/s0009-2614(99)00136-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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37
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Zhao X, Wang D, Spiro TG. A UV Resonance Raman Monitor of Histidine Protonation in Proteins: Bohr Protons in Hemoglobin. J Am Chem Soc 1998. [DOI: 10.1021/ja974040n] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaojie Zhao
- Department of Chemistry, Princeton University Princeton, New Jersey 08544
| | - Daojing Wang
- Department of Chemistry, Princeton University Princeton, New Jersey 08544
| | - Thomas G. Spiro
- Department of Chemistry, Princeton University Princeton, New Jersey 08544
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38
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Ackers GK. Deciphering the molecular code of hemoglobin allostery. ADVANCES IN PROTEIN CHEMISTRY 1998; 51:185-253. [PMID: 9615171 DOI: 10.1016/s0065-3233(08)60653-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- G K Ackers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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