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BRESLOW ESTHER, STAHL GLENNL, WALTER RODERICH. (L-2-HYDROXY-3-MERCAPTOPROPIONIC-ACID)OXYTOCIN. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1980.tb02907.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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ABERCROMBIE DAVIDM, KANMERA TATSUHIKO, ANGAL SAROJANI, TAMAOKI HIDETSUNE, CHAIKEN IRWINM. Cooperative interactions in neurophysin-neuropeptide hormonecomplexes. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1984.tb00950.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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Eubanks S, Nguyen TL, Peyton D, Breslow E. Modulation of dimerization, binding, stability, and folding by mutation of the neurophysin subunit interface. Biochemistry 2000; 39:8085-94. [PMID: 10891091 DOI: 10.1021/bi0001527] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bovine neurophysins, which have typically served as the paradigm for neurophysin behavior, are metastable in their disulfide-paired folded state and require ligand stabilization for efficient folding from the reduced state. Studies of unliganded porcine neurophysin (oxytocin-associated class) demonstrated that its dimerization constant is more than 90-fold greater than that of the corresponding bovine protein at neutral pH and showed that the increased dimerization constant is accompanied by an increase in stability sufficient to allow efficient folding of the reduced protein in the absence of ligand peptide. Using site-specific mutagenesis of the bovine protein and expression in Escherichia coli, the functional differences between the bovine and porcine proteins were shown to be attributable solely to two subunit interface mutations in the porcine protein, His to Arg at position 80 and Glu to Phe at position 81. Mutation of His-80 alone to Arg had a relatively small impact on dimerization, while mutation to either Glu or Asp markedly reduced dimerization in the unliganded state, albeit with apparent retention of the positive linkage between dimerization and binding. Comparison of the peptide-binding constants of the different mutants additionally indicated that substitution of His-80 led to modifications in binding affinity and specificity that were independent of effects on dimerization. The results demonstrate the importance of the carboxyl domain segment of the subunit interface in modulating neurophysin properties and suggest a specific contribution of the energetics of ligand-induced conformational change in this region to the overall thermodynamics of binding. The potential utility to future studies of the self-folding and monomeric mutants generated by altering the interface is noted.
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Affiliation(s)
- S Eubanks
- Department of Biochemistry, The Joan and Sanford I. Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10021, USA
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Doyle ML, Holt JM, Ackers GK. Effects of NaCl on the linkages between O2 binding and subunit assembly in human hemoglobin: titration of the quaternary enhancement effect. Biophys Chem 1997; 64:271-87. [PMID: 9127950 DOI: 10.1016/s0301-4622(96)02235-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Oxygen binding by human hemoglobin (Hb) and the coupled reactions of dimer-tetramer assembly were studied over a range of NaCl concentrations (from 0.08 M to 1.4 M) at pH 7.4 and 21.5 degrees C. A strategy of multi-dimensional analysis was employed [G.K. Ackers and H.R. Halvorson, Proc. Natl. Acad. Sci. U.S.A., 91, (1974) 4312] to optimize the resolution of the contributions to cooperativity and their heterotropic salt linkages at each stoichiometric degree of O2 binding. A wide range of Hb concentration was utilized at each [NaCl] in which O2-linked subunit assembly reactions contributed significantly to the positions and shapes of the binding isotherms. Kinetic determinations yielded forward and reverse rate constants for assembly of the unligated species. Amplitudes for the assembly rate data had concentration dependences in agreement with the independently determined dimer-tetramer assembly constants of oxyhemoglobin. Concentration-dependent binding isotherms were analyzed, in combination with the kinetically determined equilibrium constants, to yield salt-linked components of cooperativity at the four stages of oxygenation. The principal results of this study were as follows. (i) Assembly of fully oxygenated Hb tetramers is opposed by NaCl: the dimer-to-tetramer equilibrium constant becomes two orders of magnitude less favorable over the [NaCl] range 0.08 M to 1.4 M. By contrast, for deoxy-Hb the assembly equilibrium constant is reduced only two-fold. (ii) Oxygen binding to dimers is non-cooperative over the entire salt range, whereas dimer affinity is slightly favored by increasing the NaCl concentration. (iii) Overall affinity of tetramers for O2 is opposed by NaCl, becoming an order of magnitude less favorable over the range employed. Most of this decrease occurs at the fourth binding step, which shows a large, salt-mediated quaternary enhancement effect; i.e., the assembly of dimers into tetramers at 0.08 M NaCl is accompanied by an eight-fold increase in O2 affinity. (iv) The quaternary enhancement effect at the last O2-binding step is titrated progressively by salt until it reaches a negligible value near the highest [NaCl] of this study. The lowest [NaCl] condition (0.08 M) elicits the greatest tetramer cooperativity with the largest maximal Hill coefficient and the greatest suppression of intermediates. Possible origins and mechanistic implications of these phenomena are considered.
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Affiliation(s)
- M L Doyle
- Macromolecular Sciences Department, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406, USA
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5
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Abstract
A synthetic procedure was developed for the direct immobilization on preactivated affinity supports of peptidic ligands requiring free alpha-amino groups to recognize their targets properly. The peptidic ligand is assembled by solid-phase peptide synthesis on an octa-branched heptalysine core through a polyglycine spacer, similar to the method developed for the production of multiple antigenic peptides. After deblocking from the resin, peptide is dialysed, lyophylized and used directly for coupling to preactivated supports. Following immobilization, only a limited number of peptide chains are covalently linked to the solid phase, leaving the remainder facing the mobile phase and sufficiently spaced to interact properly. This procedure was applied successfully to the design, synthesis and oriented immobilization of a multimeric tripeptide ligand (Met-Tyr-Phe) for affinity purification of bovine neurophysin.
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Affiliation(s)
- G Fassina
- Protein Engineering Unit, Tecnogen ScpA, Milan, Italy
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Hasselbacher CA, Schwartz GP, Glass JD, Laws WR. Neurophysin-neurohypophyseal hormone interactions: studies using a dansylated vasotocin analogue. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1991; 38:459-68. [PMID: 1820072 DOI: 10.1111/j.1399-3011.1991.tb01527.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have synthesized a neurohypophyseal hormone analogue containing an extrinsic fluorescence probe by linking a dansyl (DNS) group to the epsilon-amino group of the lysine at residue 8 of vasotocin. The fluorescence properties of this analogue have been characterized by steady-state and time-resolved spectroscopic methods and compared with those of epsilon-DNS-lysine and the dansylated carboxyl terminal tripeptide Pro-Lys(DNS)-GlyNH2. The binding of this hormone analogue to purified isoforms of bovine neurophysins, the natural carrier proteins of the neurohypophyseal hormones, results in changes in several fluorescence parameters of the dansyl probe. These changes include an increase in intensity and average lifetime, a shift of the emission band to higher energies, and an increase in the emission anisotropy. Anisotropy changes have been used to determine dissociation constants for binding to these neurophysin isoforms. Based on the changes in the fluorescence properties of the dansyl probe, the dansyl group itself interacts with the protein. The degree of the dansyl-neurophysin interaction, however, appears to be different for the full sequence isoform of neurophysin I and the Val89 isoform of neurophysin II.
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Affiliation(s)
- C A Hasselbacher
- Department of Biochemistry, Mount Sinai School of Medicine, New York, NY
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Chun PW, Milov DE, Jou WS. Quantitative reappraisal of general expressions for multivalent protein binding in subunit-exchange chromatography. Biophys Chem 1990; 38:131-41. [PMID: 2085648 DOI: 10.1016/0301-4622(90)80048-c] [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: 12/30/2022]
Abstract
Quantitative expressions have been derived for bivalent equilibria with immobilized ligand systems and for the equilibria for an immobilized protein whose self-association is modified by binding with a soluble ligand, as analyzed by affinity chromatography. These general expressions have been applied in a reexamination of multivalency in the affinity chromatography of antibodies, as reported by Eilat and Chaiken (Biochemistry 18 (1979) 790) and also to studies of neurophysin-peptide hormone interactions using glass matrices reported by Swaisgood and Chaiken (Biochemistry 25 (1986) 4148).
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Affiliation(s)
- P W Chun
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville 32610
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8
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Structural requirements of peptide hormone binding for peptide-potentiated self-association of bovine neurophysin II. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68275-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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9
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Abercrombie DM, Chaiken IM. Oxytocin and vasopressin: photoaffinity labeling of neurophysins, secretory granule hormone-binding proteins. Pharmacol Ther 1987; 33:209-19. [PMID: 3310032 DOI: 10.1016/0163-7258(87)90065-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- D M Abercrombie
- Molecular, Cellular, and Nutritional Endocrinology Branch, National Institute of Arthritis, Bethesda, Maryland 20892
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10
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Scarlata SF, Royer CA. Ligand-induced asymmetry as observed through fluorophore rotations and free energy couplings: application to neurophysin. Biochemistry 1986; 25:4925-9. [PMID: 3768323 DOI: 10.1021/bi00365a030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Changes that occur in subunit neurophysin structure upon ligand binding were explored by two methods. First, the thermal coefficient of the viscosity around the subunit tyrosine was monitored, which yields information on the environmental flexibility and free rotational space of the fluorophore. Initially, it was determined that the environmental flexibility and the free space around each subunit tyrosine are unperturbed upon dimerization. Binding of the tripeptide analogue of oxytocin causes the once homologous environments of the subunit tyrosines to become drastically different such that one moves onto a closely packed environment whereas the other moves into a region of larger free space. Even though the subunits as seen by each tyrosine are very different, the specific binding sites as seen by the ligands are similar. It was also found that ligand binding is stabilized by ring stacking and that energy transfer occurs between the tyrosine of the ligand and the neurophysin subunit tyrosine. Second, changes in subunit structure upon ligation were also followed by the determination of the order of free energy coupling between ligand binding and oligomerization, which tells how each ligand affects the subunit affinity. Since the binding of ligand is cooperative and induces dimer formation, there is second-order coupling between ligand binding and dimerization and the binding of the second ligand is responsible for the increase in subunit affinity.
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Swaisgood HE, Chaiken IM. Analytical high-performance affinity chromatography: evaluation by studies of neurophysin self-association and neurophysin-peptide hormone interaction using glass matrices. Biochemistry 1986; 25:4148-55. [PMID: 3741847 DOI: 10.1021/bi00362a024] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bovine neurophysin II (BNP II) was covalently immobilized on both nonporous and porous (200-nm pore diameter) glass beads and incorporated in a high-performance liquid chromatograph to evaluate analytical high-performance affinity chromatography as a microscale method for characterizing biomolecular interactions. By extension of the theoretical treatment of analytical affinity chromatography, both the self-association of neurophysin and its binding of the peptide hormone vasopressin were characterized by using a single chromatographic column containing immobilized neurophysin predominantly in the monomer form. Both [3H] [Arg8]vasopressin (AVP) and 125I-BNP II were rapidly eluted (less than 25 min). The relatively symmetrical elution peaks obtained allowed calculation of both equilibrium dissociation constants and kinetic dissociation rate constants. The dissociation constant measured chromatographically for the AVP-immobilized neurophysin complex, KM/L = 11 microM with porous glass beads and 75 microM with nonporous glass (NPG) beads, was in reasonable agreement with those previously obtained by curve fitting of Scatchard plots (16-20 microM) and from binding to [BNP II]Sepharose (50 microM). The values obtained are larger than that for dissociation of AVP from BNP II dimer, by a factor consistent with the intended nature of immobilized BNP II as monomers. Chromatography of BNP II on the [BNP II]NPG gave a dimer dissociation constant of 166 microM, a value in excellent agreement with that derived from equilibrium sedimentation studies (172 microM). In contrast to the agreement of chromatographic equilibrium binding constants with those measured in solution, the dissociation rate, k-3, determined from the variance of the affinity chromatographic elution profile with nonporous beads, was several orders of magnitude smaller than the solution counterpart.(ABSTRACT TRUNCATED AT 250 WORDS)
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12
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Nichol LW, Winzor DJ. Calculation of asymptotic boundary shapes from experimental mass migration patterns. Methods Enzymol 1986; 130:6-18. [PMID: 3773751 DOI: 10.1016/0076-6879(86)30004-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Nichol LW, Winzor DJ. The binding of a ligand to an acceptor undergoing indefinite self-association. J Theor Biol 1985; 117:597-608. [PMID: 4094454 DOI: 10.1016/s0022-5193(85)80241-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Explicit expressions are derived which describe the binding of a univalent ligand to equivalent and independent sites on each state of an acceptor undergoing indefinite self-association that is governed by an isodesmic equilibrium constant KI. From considerations of systems in which the same site-binding constant kA applies to all acceptor-ligand interactions, the general forms of binding curves and Scatchard plots are deduced for situations in which binding sites are either created or lost at each monomer-monomer interface. Greater generality is then introduced into the model by allowing ligand interactions with polymeric acceptor states to be governed by a site-binding constant kp that differs in magnitude from that for monomeric acceptor kA. Finally, experimental results with the glutamate dehydrogenase-GTP and lysozyme-saccharide systems are used to illustrate ways in which the present quantitative expressions may be applied to the characterization of inteactions between a ligand and an indefinitely self-associating acceptor.
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Whittaker BA, Allewell NM, Carlson J, Breslow E. Enthalpies of ligand binding to bovine neurophysins. Biochemistry 1985; 24:2782-90. [PMID: 4027226 DOI: 10.1021/bi00332a028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Flow microcalorimetry and batch microcalorimetry have been used to survey the energetics of ligand binding by bovine neurophysins I and II. Calorimetry studies were supplemented by van't Hoff analyses of binding constants determined by circular dichroism. Free energies of binding of a series of di- and tripeptides that bind to the strong hormone binding site of neurophysin were partitioned into their enthalpic and entropic components. The results indicate that, at 25 degrees C, the binding of most peptides is an enthalpy-driven reaction associated with negative entropy and heat capacity changes. Studies elsewhere, supported by evidence here, indicate that the principal component of the negative enthalpy change does not arise from the increase in neurophysin dimerization associated with peptide binding. Accordingly, the negative enthalpy change is attributed to direct bonding interactions with peptide and possibly also to peptide-induced changes in tertiary or quaternary organization. Comparison of the binding enthalpies of different peptides indicated two types of bonding interactions that contribute to the negative enthalpy change of peptide ligation. Substitution of an aromatic- or sulfur-containing side chain for an aliphatic side chain in position 1 of bound peptides led to increases in negative enthalpy of from 1 to 6 kcal/mol, demonstrating that interactions typically classified as hydrophobic can have a significant exothermic component at 25 degrees C. Similarly, loss of hydrogen bonding potential in the peptide decreased the enthalpy change upon binding, in keeping with the expected enthalpic contribution of hydrogen bonds. In particular, the data suggested that the peptide backbone between residues 2 and 3 and the phenolic hydroxyl group in position 2 participate in hydrogen bonding.(ABSTRACT TRUNCATED AT 250 WORDS)
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Na GC, Timasheff SN. Measurement and analysis of ligand-binding isotherms linked to protein self-associations. Methods Enzymol 1985; 117:496-519. [PMID: 4079813 DOI: 10.1016/s0076-6879(85)17027-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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16
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Chaiken IM. Neurophysin-neuropeptide hormone complexes: biosynthetic origin and noncovalent interactions. Biopolymers 1983; 22:355-62. [PMID: 6673764 DOI: 10.1002/bip.360220146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Rholam M, Nicolas P, Cohen P. Binding of neurohypophyseal peptides to neurophysin dimer promotes formation of compact and spherical complexes. Biochemistry 1982; 21:4968-73. [PMID: 7138841 DOI: 10.1021/bi00263a021] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Previous hydrodynamic studies [Rholam, M., & Nicolas, P. (1981) Biochemistry 20, 5837-5843] have demonstrated that the dimerization of a neurophysin monomer (prolate ellipsoid with an axial ratio, due to asymmetry, of 5.2) results in a decreased asymmetry (axial ratio, due to asymmetry, of 3.6) as the consequence of a side-by-side association process. By a combination of hydrodynamic measurements, including the use of sedimentation velocity, viscometry, and fluorescence polarization spectroscopy, the influence of hormone binding on the shape and asymmetry properties of the neurophysin dimer was evaluated. The binding of ocytocin, vasopressin, and the tripeptide analogue of the N-terminal sequence of ocytocin, Cys(S-Me)-Tyr-Ile-NH2, results in an increase of S020,W and a decrease in both the reduced viscosity and rotational relaxation time of the bis-liganded dimeric species vs. the nonliganded form. The axial ratio (a/b) due to asymmetry of the ligand-bound dimers was found in each case to be equal to, or slightly greater than, 1.0, indicating a compact spherical shape (Stokes radius 21 A). The profound alteration on molecular dimensions observed upon ligand binding is shown to be the consequence of a ligand-induced conformational change and might explain the intradimeric binding sites positive cooperativity. It is tentatively proposed that the pseudospherical shape of the neurophysin-hormone complexes may enhance the stability of neurophysin and contribute to the prevention of leakage of neuropeptides through the membrane of neurosecretory granules. The data provide a remarkable example of a small protein with a high content in disulfide links and that undergoes conspicuous changes in conformation under the influence of nonapeptide, or tripeptide, ligands.
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18
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Abercrombie DM, McCormick WM, Chaiken IM. Photoaffinity labeling of the hormone binding site of neurophysin. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34917-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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19
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Tauc P, Leconte C, Kerbiriou D, Thiry L, Hervé G. Coupling of homotropic and heterotropic interactions in Escherichia coli aspartate transcarbamylase. J Mol Biol 1982; 155:155-68. [PMID: 7042988 DOI: 10.1016/0022-2836(82)90442-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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20
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Rholam M, Nicolas P. Side-by-side dimerization of neurophysin: sedimentation velocity, viscometry, and fluorescence polarization studies. Biochemistry 1981; 20:5837-43. [PMID: 7295705 DOI: 10.1021/bi00523a029] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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21
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Lord ST, Breslow E. Synthesis of peptide spin-labels that bind to neurophysin and their application to distance measurements within neurophysin complexes. Biochemistry 1980; 19:5593-602. [PMID: 7459333 DOI: 10.1021/bi00565a021] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The synthesis of two spin-labels capable of binding to the hormone-binding site(s) of neurophysin is described. The two spin-labels are 4-(glycyl-L-phenylalanylamido)-2,2,6,6-tetramethylpiperidinyl-1-oxy and S-[[[3-(2,2,5,5-tetramethylpyrrolidine-1-oxy)amino]carbonyl]methyl]-L-cysteinyl -L-tyrosine amide; synthesis of the former is achieved by a novel route to circumvent problems associated with nitroxide instability under standard conditions of peptide deblocking. NMR studies of the effects of binding these spin-labels on relaxation rates of individual proton resonances of neurophysin were used to calculate correlation times and distances between the bound nitroxides and the observed protons. The results indicate that residue 3 of peptides bound to the strong site of neurophysin is greater than or equal to 14 A from Tyr-49 and argue against a distance of < 5 A between the ortho ring protons of Tyr-49 and those of residue 2 of peptides bound to the strong site. Alternatively, the data suggest that the previously observed nuclear Overhauser effect between these protons reflects spin diffusion at the strong site and a contribution of uncertain magnitude from a second but very weak binding site; this second site is close to Tyr-49 and is detected by the increased relaxation rate of Tyr-49 ring protons when 4-(glycyl-L-phenylalanylamido)-2,2,6,6-tetramethylpiperidinyl-1-oxy is displaced from the strong site by competing diamagnetic peptide. Additionally, the data indicate that residue 3 of bound peptides at the strong site is distant from His-80 but approximately 12 A from the amino terminus. The extended side chain of residue 1 of peptides at the strong site is calculated as less than or equal to 10 A from Tyr-49.
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Pearlmutter AF, Dalton EJ. Stopped-flow investigation of nitrated bovine neurophysin monomer binding to oxytocin. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1980; 16:477-81. [PMID: 7216623 DOI: 10.1111/j.1399-3011.1980.tb02972.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
By use of stopped-flow kinetic data, we have measured the kinetics of mononitrated neurophysin I monomer binding to oxytocin. The association constant was 1.3(+/-0.3) x 10(5) M-1s-1 and the dissociation rate constant was 2.0(+/-0.5)s-1 for protonated oxytocin binding. Both rates are significantly slower than those observed for neurophysin dimer. These data suggest that the binding process by which the monomer binds oxytocin is not identical to that of dimer.
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Tellam R, Winzor DJ. Effect of phosphate on the macromolecular state of bovine neurophysin. Arch Biochem Biophys 1980; 201:20-4. [PMID: 7396497 DOI: 10.1016/0003-9861(80)90482-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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24
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Sawada Y, Audhya TK, Walter R. Bovine neurophysin lipid complex. Their isolation, characterization and reaggregation. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1979; 14:317-25. [PMID: 521214 DOI: 10.1111/j.1399-3011.1979.tb01939.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A lipid-containing neurophysin fraction was isolated and purified from bovine posterior pituitary glands by acid extraction and affinity chromatography on a heparin-Sepharose 4B column. This lipid-rich fraction was found to be composed of noncovalent aggregates of neurophysin proteins and phospholipids such as phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl serine and sphingomyelin. The lipid-containing neuophysin was delipidated by treatment with choloform-methanol. The resultant apoproteins were characterized as bovine neuroions were developed for the reaggregation of purified bovine neurophysin-I and -II with lipids extracted from bovine posterior pituitary and hypothalamus and with synthetic lecithin. The resultant neurophysin lipid complexes have been shown to band upon isopycnic centrifugation at densities different from those of the respective purified bovine neurophysins.
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Chaiken IM. Preparative and analytical affinity chromatography of neurophysins on methionyl-tyrosyl-phenylalanyl-aminohexyl-agarose. Anal Biochem 1979; 97:302-8. [PMID: 525794 DOI: 10.1016/0003-2697(79)90076-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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26
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Audhya TK, Seif SM, Robinson AG, Krieger DT, Arruda JA, Kurtzman NA, Walter R. Biological and immunological studies of lipid-containing neurophysin of rat and reaggregated lipid complex. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 572:483-91. [PMID: 219896 DOI: 10.1016/0005-2760(79)90155-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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27
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28
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Lord ST, Breslow E. Identification and observation of alkyl proton resonances of the amino-terminal residues of bovine neurophysins. Evidence for conformational differences between neurophysin-I and neurophysin-II. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1979; 13:71-7. [PMID: 33930 DOI: 10.1111/j.1399-3011.1979.tb01851.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Analysis of the 220 MHz proton magnetic resonance spectra of bovine neurophysins-I and -II and of the effects of pH and succinylation of these spectra has allowed identification of the -CH3 proton resonances of the amino-terminal alanine of both proteins and of the -CH3 resonances of methionine-2 of neurophysin-II. The alanine -CH3 resonance of neurophysin-I is a sharp doublet at all pH values between 1 and 10.5 indicating relatively few restrictions on its mobility. By contrast, the -CH3 resonances of the amino-terminal alanine and methionine-2 of neurophysin-II undergo pH-dependent changes in broadening compatible with the formation of an intramolecular salt-bridge at neutral pH between the protonated alpha-amino and an unprotonated side chain carboxyl. The results suggest that differeces in the properties of the two proteins are partially mediated by conformational differences involving their amino-terminal sequences. The potential usefulness of the amino-terminal resonances as n.m.r. 'reporter' signals is additionally demonstrated by studies of the effects of spin labels on the neurophysin-I amino-terminal alanine resonance; these studies place the amino-terminus of neurophysin-I approximately 14 A from residue 3 of peptides bound to the strong neurophysin hormone-binding site.
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Deslauriers R, Smith IC, Stahl GL, Walter R. Studies of the interaction of bovine neurophysin-II with [1-hemi-D-(3-13C)cystine] oxytocin and [1-hemi-(3-13C)cystine] oxytocin. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1979; 13:78-87. [PMID: 33931 DOI: 10.1111/j.1399-3011.1979.tb01852.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Audhya T, Walter R. Neurophysin.lipid complexes. Characterization of lipid-containing neurophysin from rat posterior pituitary, delipidation, and reaggregation. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)37917-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Cohen P, Nicolas P, Camier M. Biochemical aspects of neurosecretion: neurophysin--neurohypophyseal hormone complexes. CURRENT TOPICS IN CELLULAR REGULATION 1979; 15:263-318. [PMID: 527370 DOI: 10.1016/b978-0-12-152815-7.50011-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Blumenstein M, Hruby VJ, Yamamoto DM. Evidence from hydrogen-1 and carbon-13 nuclear magnetic resonance studies that the dissociation rate of oxytocin from bovine neurophysin at neutral pH is slow. Biochemistry 1978; 17:4971-7. [PMID: 31171 DOI: 10.1021/bi00616a018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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33
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Baghurst PA, Nichol LW, Winzor DJ. Conditions for the existence of critical points in Scatchard plots of binding results. J Theor Biol 1978; 74:523-34. [PMID: 732342 DOI: 10.1016/0022-5193(78)90239-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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34
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Nicolas P, Wolff J, Camier M, Di Bello C, Cohen P. Importance of neurophysin dimer and of tyrosine-49 in the binding of neurohypophyseal peptides. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)40868-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Lord ST, Breslow E. Nuclear magnetic resonance spin label studies of neurophysin: evidence for secondary peptide-binding sites. Biochem Biophys Res Commun 1978; 80:63-70. [PMID: 564188 DOI: 10.1016/0006-291x(78)91104-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Bonne D, Nicolas P, Lauber M, Camier M, Tixier-vidal A, Cohen P. Evidence for an adenylate-cyclase activity in neurosecretory granule membranes from bovine neurohypophysis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 78:337-42. [PMID: 913403 DOI: 10.1111/j.1432-1033.1977.tb11745.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Purified bovine neurosecretory granules and their corresponding membranes were prepared after fractionation and purification processes from bovine pituitaries. An adenylate cyclase activity was detected both in the granules (apparent Km = 0.5 mM) and the corresponding preparations of the membranes (apparent Km = 0.5 mM). This enzyme was activated by fluoride in a way markedly dependent on the concentration of this ion, and with a maximum for a concentration of F- = 3.5 mM. The cyclase activity was also significantly enhanced by GTP. The reaction rate showed a strong dependence on the molar ration [Mg2+]/[ATP] with maximal velocity for 7. It is suggested that this activity might play an important role in the control and regulation of neurosecretion in the neurohypophysis.
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