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Hellmann N. Control of kinetics by cooperative interactions. IUBMB Life 2011; 63:329-36. [DOI: 10.1002/iub.459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 02/23/2011] [Indexed: 11/11/2022]
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2
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Hartmann H, Bongers A, Decker H. Small-angle X-ray Scattering-based Three-dimensional Reconstruction of the Immunogen KLH1 Reveals Different Oxygen-dependent Conformations. J Biol Chem 2004; 279:2841-5. [PMID: 14573592 DOI: 10.1074/jbc.m308959200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For decades the respiratory protein keyhole limpet hemocyanin (KLH1) from the marine gastropod Megathura crenulata has been used widely as a potent immunostimulant, useful hapten carrier, and valuable agent in the treatment of bladder carcinoma. Although much information on the immunological properties of KLH1 is available, biochemical and structural data are still incomplete. Small-angle x-ray scattering revealed the existence of two conformations, an oxy state being slightly more compact than the deoxy state. Based on small-angle scattering curves, a newly developed Monte Carlo algorithm delivered a surface representation of proteins. The massive changes of the surfaces of reconstructed didecameric KLH1 molecules are explained as a twist of the two non-covalently associated decameric half-molecules. Upon oxygenation, the KLH1 molecule becomes longer and skinnier. This study provides the first real evidence how a molluscan hemocyanin changes conformation during an allosteric transition.
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Affiliation(s)
- Hermann Hartmann
- Institut für Molekulare Biophysik, Universität Mainz, D-55099 Mainz, Germany.
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3
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Brouwer M, Brouwer-Hoexum T. Glutathione-mediated transfer of copper(I) into American lobster apohemocyanin. Biochemistry 1992; 31:4096-102. [PMID: 1567855 DOI: 10.1021/bi00131a028] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Copper in the cytosol of the hepatopancreas of the American lobster, Homarus americanus, occurs as copper-metallothionein [Cu(I)-MT] and as a copper-glutathione complex [Cu(I)-GSH]. The latter can act in vitro as the source of Cu(I) in the reconstitution of lobster apohemocyanin, whereas Cu(I)-MT cannot. Here we report on the mechanism of the GSH-mediated reconstitution. Binding of Cu(I) to apohemocyanin was measured by its effect on the protein's fluorescence, by ultrafiltration experiments and size-exclusion HPLC. Reconstitution of CO and O2 binding was studied using the [Cu(I)...Cu(I)-CO] fluorescence of hemocyanin and its Cu-O2-Cu charge-transfer band as spectral probes. The hemocyanin oligomer has 1 (1.02 +/- 0.09) high-affinity (apparent Kdiss = 1.67 +/- 0.40 microM) external binding site for ionic Cu(I) per subunit. Binding of Cu(I) to this site is fast and reversible and is followed by a slow, irreversible incorporation of copper into the protein matrix. Movement of the first copper through the matrix to the active site is the rate-limiting step in the reconstitution process. Mononuclear copper sites, once formed, are rapidly converted into biologically active, binuclear copper sites. In accordance with this reaction sequence, the restoration of CO/O2 binding by hemocyanin is a first-order reaction with a half-time of 100 +/- 5 min at pH 6.0. Reconstitution is extremely pH-dependent and proceeds best at those pH values where the architecture of the copper pocket of hemocyanin is open as judged from its extremely low affinity for oxygen and its very fast oxygen dissociation rate.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Brouwer
- Duke University School of the Environment, Duke University Marine Laboratory, Beaufort, North Carolina 28516
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4
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Phillipson PE. An analytic model for kinetics of hemoglobin reacting with ligand. Biophys Chem 1990; 37:91-5. [PMID: 2285806 DOI: 10.1016/0301-4622(90)88010-p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The saturation function Y(t) descriptive of the kinetics of ligand binding by a biological macromolecule such as hemoglobin can be represented by Y(t) = Yeq ([1 + epsilon][1-exp-(sigma 1t])/([1 + epsilon]-epsilon exp-(sigma 1t]), where Yeq is the fraction of sites bound at equilibrium, and sigma 1 and epsilon are parameters which can be determined by kinetics measurements. If the sites bind independently, fixed functional relations hold between the quantities (Yeq, sigma 1, epsilon). These relations do not hold for cooperative ligand binding. The departures of these quantities from that required by the independent sites relations provide a measure of cooperativity. The present formulation, which includes the approximation that the multiplicity of chemical relaxation processes are dominated by a single one, can be extended for more refined applications.
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Affiliation(s)
- P E Phillipson
- Department of Physics, University of Colorado, Boulder 80309-0390
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Samson MR, Klis FM, Homan WL, van Egmond P, Musgrave A, van den Ende H. Composition and properties of the sexual agglutinins of the flagellated green alga Chlamydomonas eugametos. PLANTA 1987; 170:314-321. [PMID: 24232960 DOI: 10.1007/bf00395022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/1986] [Accepted: 11/13/1986] [Indexed: 06/02/2023]
Abstract
Sexual interaction between gametes of opposite mating type (mt) of the unicellular green alga Chlamydomonas eugametos starts with agglutination of the cells via particular glycoproteins on the flagellar surface. Purification of these socalled agglutinins was achieved by a three-step procedure consisting of, successively, gel filtration, anion-exchange chromatography, and high-performance gel filtration. The amino-acid and sugar compositions of both agglutinins showed a high degree of similarity; the most prominent amino acids were hydroxyproline, serine and glycine, and the main sugars were arabinose and galactose. The carbohydrate portions represented about half of the molecular mass of both agglutinins. Using high-performance gel filtration, a calibration curve was constructed for high-molecular-mass compounds from which the Stokes' radius of the sexual agglutinins could be estimated. The mt (+) agglutinin had a Stokes' radius of 39 nm and a sedimentation coefficient of 9.3 S. From these data its molecular mass was estimated to be 1.2·10(6). The corresponding data for the mt (-) agglutinin were 38 nm, 9.7 S and 1.3·10(6), respectively. The biological activity of both agglutinins was destroyed by mild periodate treatment. Treatment with specific glycosidases had a differential effect on the biological activity of the agglutinins. These observations indicate that carbohydrate side-chains are needed for biological activity and perhaps are responsible for the specifity of the sexual agglutinins. A comparison of both agglutinins is given and their possible structure is discussed in relation to their amino-acid and sugar compositions.
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Affiliation(s)
- M R Samson
- Department of Plant Physiology, University of Amsterdam, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands
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Zolla L, Brunori M, Richey B, Gill SJ. Heterogeneous binding of oxygen and carbon monoxide to dissociated molluscan hemocyanin. Biophys Chem 1985; 22:271-80. [PMID: 17007787 DOI: 10.1016/0301-4622(85)80050-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/1985] [Revised: 06/01/1985] [Accepted: 06/07/1985] [Indexed: 11/16/2022]
Abstract
Functional heterogeneity in O2 or CO binding of sites of dissociated molluscan hemocyanin polypeptide chains (Helix pomatia and Octopus vulgaris) has been estimated by an analysis of accurate noncooperative binding curves. Three types of experiments were performed: pure O2 or CO binding, competitive displacement of one ligand by the other, and simultaneous removal of both gases from protein partially saturated with O2 and CO. The data were analyzed in terms of a model which has two fractions of sites with different properties for O2 and CO. The relative proportion of the different binding sites and their affinity constant values were found by the combined use of the three different procedures. All species show a marked functional heterogeneity of sites for O2 binding, while for CO binding it has been observed only in the case of H. pomatia beta-hemocyanin. Moreover, in all three molluscan hemocyanins examined, the two classes of O2-binding sites, although present in different proportions within the polypeptide chains, display similar affinity constant values. The data reported show a good consistency with results obtained using digested and isolated domains, providing confidence in the analytical procedure used. From comparison of the O2/CO affinity ratios (KO2, KCO) of each class it may be suggested that the difference in O2 affinity of two kinds of binding sites is related to a different local structure of the active sites. The results, moreover, unequivocally confirm that binding and displacement of two gaseous ligands to hemocyanin occur by a simple competitive mechanism, although the binding site is structurally complex and the two ligands are bound with different geometries.
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Affiliation(s)
- L Zolla
- Institute of Chemistry, Faculty of Medicine and CNR Center of Molecular Biology, University of Rome 'La Sapienza', 00185 Rome, Italy
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Ellerton HD, Ellerton NF, Robinson HA. Hemocyanin--a current perspective. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1983; 41:143-248. [PMID: 6348872 DOI: 10.1016/0079-6107(83)90028-7] [Citation(s) in RCA: 143] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Kinetics of the equilibration of oxygen with monomeric and octameric hemerythrin from Themiste zostericola. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0005-2795(81)90110-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Torensma R, van der Laan JM, van Bruggen EF. Structural and functional aspects of collar domains of Helix pomatia beta c-hemocyanin. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 668:268-76. [PMID: 7225411 DOI: 10.1016/0005-2795(81)90034-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Digestion of beta c-hemocyanin yielded tubular polymers as well as so-called collars. Analysis of the collar fraction revealed that it consisted of two fragments, one having a relative molecular mass of approx. 125000 and the other a relative molecular mass of approx. 65000. They were separated using ion-exchange chromatography. The large fragment dissociated around pH 9.5 into two components having a molecular mass of approx. 65000. Both fragments bound oxygen and displayed heterotropic interactions. The large fragment bound oxygen with a Hill coefficient less than unity under certain conditions. The fragments differed also in amino acid composition, sugar content, spectral parameters, association-dissociation phenomena and ageing. by comparison with fragments obtained after limited proteolysis of tenth molecules, their location in the polypeptide chain was established.
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Brouwer M, Bonaventura C, Bonaventura J. Effect of oxygen and allosteric effects on structural stability of oligomeric hemocyanins of the arthropod, Limulus polyphemus, and the mollusc, Helix pomatia. Biochemistry 1981; 20:1842-8. [PMID: 7225359 DOI: 10.1021/bi00510a020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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386 - Polarographic studies on perfluorocarbon emulsion, hemoglobin and erythrocyte as oxygen carriers. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0302-4598(80)87006-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Takagi M, Hayashi K. Polarographic studies on perfluorocarbon emulsion, hemoglobin and erythrocyte as oxygen carriers. J Electroanal Chem (Lausanne) 1980. [DOI: 10.1016/s0022-0728(80)80244-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Brouwer M, Ryan M, Bonaventura J, Bonaventura C. Functional and structural properties of Murex fulvescens hemocyanin: isolation of two different subunits required for reassociation of a molluscan hemocyanin. Biochemistry 1978; 17:2810-5. [PMID: 28744 DOI: 10.1021/bi00607a017] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zolla L, Kuiper HA, Vecchini P, Antonini E, Brunori M. Dissociation and oxygen-binding behaviour of beta-hemocyanin from Helix pomatia. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 87:467-73. [PMID: 28226 DOI: 10.1111/j.1432-1033.1978.tb12397.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Kuiper HA, Brunori M, Antonini E. Kinetics of the Bohr effect in the reaction of Helix pomatia beta-hemocyanin with oxygen. Biochem Biophys Res Commun 1978; 82:1062-9. [PMID: 29614 DOI: 10.1016/0006-291x(78)90295-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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van Driel R, Kuiper HA, Antonini E, Brunori M. Kinetics of the co-operative reaction of Helix pomatia hemocyanin with oxygen. Oxygen binding at low and intermediate oxygen saturations. J Mol Biol 1978; 121:431-9. [PMID: 671545 DOI: 10.1016/0022-2836(78)90392-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Kuiper HA, Antonini E, Brunori M. Kinetic control of co-operativity in the oxygen binding of Panulirus interruptus hemocyanin. J Mol Biol 1977; 116:569-76. [PMID: 22762 DOI: 10.1016/0022-2836(77)90084-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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van Driel R, van Bruggen EF. Functional properties of chemically modified hemocyanin. Fixation of hemocyanin in the low and the high oxygen affinity state by reaction with a bifunctional imido ester. Biochemistry 1975; 14:730-5. [PMID: 1115769 DOI: 10.1021/bi00675a013] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hemocyanin of Helix pomatia is a respiratory protein with a molecular weight of 9 times 10-6; it contains 180 oxygen binding sites. The reaction of hemocyanin with the bifunctional reagent dimethyl suberimido ester, which reacts with amino groups, has been studied. Up to 75 per cent of the amino groups can be modified without inactivation of oxygen binding sites or dissociation of the protein, It appears that hemocyanin can be fixed in a state with low oxygen affinity by modification of the deoxy protein, and in a state with high oxygen affinity by modification of the oxy protein. Using conditions under which native hemocyanin binds oxygen cooperatively (Hill coefficient 2.9), modification of deoxy- and oxyhemocyanin yields derivatives with different oxygen affinities (P50 equals 10 and 2.2 mm, respectively). Both the deoxy and oxy derivatives show strongly reduced cooperativity (Hill coefficients 1.4 and 1.1, respectively). Modification of oxy- and deoxyhemocyanin subunits (molecular weight one-tenth of the native protein), which bind oxygen noncooperatively, results in derivatives with oxygen binding properties identical with those of unmodified subunits. Parallel experiments have been carried out with a unifunctional reagent, methyl acetoimido ester. Modification of partially oxygenated hemocyanin under conditions at which the protein binds oxygen cooperatively yeilds derivatives with redued cooperativity (Hill coefficents 1.1-1.2) and an oxygen affinity depending on the oxygen saturation whivh modification had been carried out. The results are consistent with a simple two-state model for the cooperativity of oxygen binding by these giant hemocyanin molecules.
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Siezen RJ, van Bruggen EF. Structure and properties of hemocyanins. XII. Electron microscopy of dissociation products of Helix pomatia alpha-hemocyanin: quaternary structure. J Mol Biol 1974; 90:77-89. [PMID: 4453014 DOI: 10.1016/0022-2836(74)90257-5] [Citation(s) in RCA: 92] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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