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Ross LE, Xiao X, Lowe ME. Identification of amino acids in human colipase that mediate adsorption to lipid emulsions and mixed micelles. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1052-9. [PMID: 23470256 DOI: 10.1016/j.bbalip.2013.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/29/2013] [Accepted: 02/25/2013] [Indexed: 10/27/2022]
Abstract
The adsorption of colipase is essential for pancreatic triglyceride lipase activity and efficient dietary fat digestion. Yet, little is known about which specific amino acids in the hydrophobic surface of colipase influence adsorption. In this study, we systematically substituted alanine or tryptophan at residues implicated in adsorption of colipase to an interface. We expressed, purified recombinant colipase mutants and characterized the ability of each alanine mutant to restore activity to lipase in the presence of bile salts. The functions of L16A, Y55A, I79A and F84A colipase were most impaired with activities ranging from 20 to 60% of wild-type colipase. We next characterized the fluorescence properties of the tryptophan mutants in the absence and presence of bile-salt-oleic acid mixed micelles. We performed steady-state emission spectra to determine peak shift and I330/I350 ratio and acrylamide quenching curves to characterize the environment of the residues. The analysis supports a model of adsorption that includes residues Leu 34 and Leu 36 on the 2nd loop, Tyr 55 and Tyr 59 on the 3rd loop and Ile 75 and Ile 79 on the 4th loop. The analysis confirms that Phe 84 is not part of the adsorption surface and likely stabilizes the conformation of colipase. Contrary to the predictions of computer modeling, the results provide strong support for an essential role of Tyr 55 in colipase adsorption to mixed micelles. The results indicate that the adsorption of colipase to mixed micelles is mediated by specific residues residing in a defined surface of colipase.
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Affiliation(s)
- Leah E Ross
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
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2
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A rapid and selective mass spectrometric method for the identification of nitrated proteins. Methods Mol Biol 2008; 477:15-29. [PMID: 19082935 DOI: 10.1007/978-1-60327-517-0_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The nitration of protein tyrosine residues represents an important posttranslational modification during development, oxidative stress, and biological aging. The major challenge in the proteomic analysis of nitroproteins is the need to discriminate modified proteins, usually occurring at substoichiometric levels, from the large amount of nonmodified proteins. Moreover, precise localization of the nitration site is often required to fully describe the biological process. Identification of the specific targets of protein oxidation was previously accomplished using immunoprecipitation techniques followed by immunochemical detection. Here, we report a totally new approach involving dansyl chloride labeling of the nitration sites which relies on the enormous potential of MS(n) analysis. The tryptic digest from the entire protein mixture is directly analyzed by MS on a linear ion trap mass spectrometer. Discrimination between nitro- and unmodified peptide is based on two selectivity criteria obtained by combining a precursor ion scan and a MS3 analysis. The novel labeling procedure was successfully applied to the identification of 3-nitrotyrosine residues in complex protein mixtures.
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3
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Amoresano A, Chiappetta G, Pucci P, D'Ischia M, Marino G. Bidimensional Tandem Mass Spectrometry for Selective Identification of Nitration Sites in Proteins. Anal Chem 2007; 79:2109-17. [PMID: 17243771 DOI: 10.1021/ac0620361] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nitration of protein tyrosine residues is very often regarded as a molecular signal of peroxynitrite formation during development, oxidative stress, and aging. However, protein nitration might also have biological functions comparable to protein phosphorylation, mainly in redox signaling and in signal transduction. The major challenge in the proteomic analysis of nitroproteins is the need to discriminate modified proteins, usually occurring at substoichiometric levels from the large amount of nonmodified proteins. Moreover, precise localization of the nitration site is often required to fully describe the biological process. Existing methodologies essentially rely on immunochemical techniques either using 2D-PAGE fractionation in combination with western blot analyses or exploiting immunoaffinity procedures to selectively capture nitrated proteins. Here we report a totally new approach involving dansyl chloride labeling of the nitration sites that rely on the enormous potential of MSn analysis. The tryptic digest from the entire protein mixture is directly analyzed by MS on a linear ion trap mass spectrometer. Discrimination between nitro- and unmodified peptide is based on two selectivity criteria obtained by combining a precursor ion scan and an MS3 analysis. This new procedure was successfully applied to the identification of 3-nitrotyrosine residues in complex protein mixtures.
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Affiliation(s)
- Angela Amoresano
- Department of Organic Chemistry and Biochemistry and School of Biotechnological Sciences, Federico II University of Naples, 80126 Napoli, Italy
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Dominguez C, Sebban-Kreuzer C, Bornet O, Kerfelec B, Chapus C, Guerlesquin F. Interactions of bile salt micelles and colipase studied through intermolecular nOes. FEBS Lett 2000; 482:109-12. [PMID: 11018532 DOI: 10.1016/s0014-5793(00)02034-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Colipase is a small protein (10 kDa), which acts as a protein cofactor for the pancreatic lipase. Various models of the activated ternary complex (lipase-colipase-bile salt micelles) have been proposed using detergent micelles, but no structural information has been established with bile salt micelles. We have investigated the organization of sodium taurodeoxycholate (NaTDC) micelles and their interactions with pig and horse colipases by homonuclear nuclear magnetic resonance (NMR) spectroscopy. The NMR data supply evidence that the folding of horse colipase is similar to that already described for pig colipase. Intermolecular nuclear Overhauser effects have shown that two conserved aromatic residues interact with NaTDC micelles.
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Affiliation(s)
- C Dominguez
- Unité de Bioénergétique et Ingénierie des Protéines, IBSM-CNRS, 31 chemin Joseph Aiguier, 13204 Marseille Cedex 20, France
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5
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Pignol D, Ayvazian L, Kerfelec B, Timmins P, Crenon I, Hermoso J, Fontecilla-Camps JC, Chapus C. Critical role of micelles in pancreatic lipase activation revealed by small angle neutron scattering. J Biol Chem 2000; 275:4220-4. [PMID: 10660587 DOI: 10.1074/jbc.275.6.4220] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the duodenum, pancreatic lipase (PL) develops its activity on triglycerides by binding to the bile-emulsified oil droplets in the presence of its protein cofactor pancreatic colipase (PC). The neutron crystal structure of a PC-PL-micelle complex (Hermoso, J., Pignol, D., Penel, S., Roth, M., Chapus, C., and Fontecilla-Camps, J. C. (1997) EMBO J. 16, 5531-5536) has suggested that the stabilization of the enzyme in its active conformation and its adsorption to the emulsified oil droplets are mediated by a preformed lipase-colipase-micelle complex. Here, we correlate the ability of different amphypathic compounds to activate PL, with their association with PC-PL in solution. The method of small angle neutron scattering with D(2)O/H(2)O contrast variation was used to characterize a solution containing PC-PL complex and taurodeoxycholate micelles. The resulting radius of gyration (56 A) and the match point of the solution indicate the formation of a ternary complex that is similar to the one observed in the neutron crystal structure. In addition, we show that either bile salts, lysophospholipids, or nonionic detergents that form micelles with radii of gyration ranging from 13 to 26 A are able to bind to the PC-PL complex, whereas smaller micelles or nonmicellar compounds are not. This further supports the notion of a micelle size-dependent affinity process for lipase activation in vivo.
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Affiliation(s)
- D Pignol
- Laboratoire de Cristallographie et de Cristallogenèse des Protéines, Institut de Biologie Structurale Jean-Pierre Ebel, CEA-CNRS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
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6
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Cordle RA, Lowe ME. The hydrophobic surface of colipase influences lipase activity at an oil–water interface. J Lipid Res 1998. [DOI: 10.1016/s0022-2275(20)32163-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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7
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Woodford JK, Behnke WD, Schroeder F. Liver fatty acid binding protein enhances sterol transfer by membrane interaction. Mol Cell Biochem 1995; 152:51-62. [PMID: 8609911 DOI: 10.1007/bf01076463] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Among the large family of fatty acid binding proteins, the liver L-FABP is unique in that it not only binds fatty acids but also interacts with sterols to enhance sterol transfer between membranes. Nevertheless, the mechanism whereby L-FABP potentiates intermembrane sterol transfer is unknown. Both fluorescence and dialysis data indicate L-FABP mediated sterol transfer between L-cell fibroblast plasma membranes occurs by a direct membrane effect: First, dansylated-L-FABP (DNS-L-FABP) is bound to L-cell fibroblast plasma membranes as indicated by increased DNS-L-FABP steady state polarization and phase resolved limiting anisotropy. Second, coumarin-L-FABP (CPM-L-FABP) fluorescence lifetimes were significantly increased upon interaction with plasma membranes. Third, dialysis studies with 3H-cholesterol loaded plasma membranes showed that L-FABP added to the donor compartment of the dialysis cell stimulated 3H-cholesterol transfer whether or not the dialysis membrane was permeable to L-FABP. However, L-FABP mediated intermembrane sterol transfer did require a sterol binding site on L-FABP. Chemically blocking the ligand binding site also inhibited L-FABP activity in intermembrane sterol transfer. Finally, L-FABP did not act either as an aqueous carrier or in membrane fusion. The fact that L-FABP interacted with plasma membrane vesicles and required a sterol binding site was consistent with a mode of action whereby L-FABP binds to the membrane prior to releasing sterol from the bilayer.
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Affiliation(s)
- J K Woodford
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati Medical Center, OH 45267-0524, USA
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Egloff MP, Sarda L, Verger R, Cambillau C, van Tilbeurgh H. Crystallographic study of the structure of colipase and of the interaction with pancreatic lipase. Protein Sci 1995; 4:44-57. [PMID: 7773176 PMCID: PMC2142970 DOI: 10.1002/pro.5560040107] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Colipase (Mr 10 kDa) confers catalytic activity to pancreatic lipase under physiological conditions (high bile salt concentrations). Previously determined 3-A-resolution X-ray structures of lipase-colipase complexes have shown that, in the absence of substrate, colipase binds to the noncatalytic C-terminal domain of pancreatic lipase (van Tilbeurgh H, Sarda L, Verger R, Cambillau C, 1992, Nature 359:159-162; van Tilbeurgh et al., 1993a, Nature 362:814-820). Upon lipid binding, conformational changes at the active site of pancreatic lipase bring a surface loop (the lid) in contact with colipase, creating a second binding site for this cofactor. Covalent inhibition of the pancreatic lipase by a phosphonate inhibitor yields better diffracting crystals of the lipase-colipase complex. From the 2.4-A-resolution structure of this complex, we give an accurate description of the colipase. It confirms the previous proposed disulfide connections (van Tilbeurgh H, Sarda L, Verger R, Cambillau C, 1992, Nature 359:159-162; van Tilbeurgh et al., 1993a, Nature 362:814-820) that were in disagreement with the biochemical assignment (Chaillan C, Kerfelec B, Foglizzo E, Chapus C, 1992, Biochem Biophys Res Commun 184:206-211). Colipase lacks well-defined secondary structure elements. This small protein seems to be stabilized mainly by an extended network of five disulfide bridges that runs throughout the flatly shaped molecule, reticulating its four finger-like loops. The colipase surface can be divided into a rather hydrophilic part, interacting with lipase, and a more hydrophobic part, formed by the tips of the fingers. The interaction between colipase and the C-terminal domain of lipase is stabilized by eight hydrogen bonds and about 80 van der Waals contacts. Upon opening of the lid, three more hydrogen bonds and about 28 van der Waals contacts are added, explaining the higher apparent affinity in the presence of a lipid/water interface. The tips of the fingers are very mobile and constitute the lipid interaction surface. Two detergent molecules that interact with colipase were observed in the crystal, covering part of the hydrophobic surface.
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Affiliation(s)
- M P Egloff
- Laboratoire de Cristallisation et Cristallographie des Macromolécules Biologiques, URA 1296-CNRS, Faculté de Médecine Nord, France
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9
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Influence of various salts on the reversed-phase retention of some dansylated amino acids in TLC. Chromatographia 1993. [DOI: 10.1007/bf02263882] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Grabowski JJ, Bertozzi CR, Jacobsen JR, Jain A, Marzluff EM, Suh AY. Fluorescence probes in biochemistry: an examination of the non-fluorescent behavior of dansylamide by photoacoustic calorimetry. Anal Biochem 1992; 207:214-26. [PMID: 1481973 DOI: 10.1016/0003-2697(92)90003-p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Photoacoustic calorimetry is shown to be a simple, precise, and accurate method for the quantification of the photophysics of a fluorescence probe, e.g., dansylamide, in a variety of solvents. This technique, which is described in detail, provides a direct measurement of the energy that is released nonradiatively following photostimulation, and can therefore be used to indirectly determine the amount of energy released via luminescent pathways. Photoacoustic calorimetry combined with established absorption and fluorescence methodologies provides a complete arsenal for characterizing the photophysical properties of many systems. Comparison of the photoacoustic signal for dansylamide versus standard compounds (ferrocene, tetraphenylethylene, 8-anilinonaphthalene-1-sulfonate, and/or 5,5'-dithiobis(2-nitrobenzoic acid) in 12 different solvents gave fh values (fraction of each absorbed 337.1-nm photon returned as heat) from a low of 0.530 in 1,4-dioxane to a high of 0.973 in water. The trend noted with solvent polarity is different and more revealing than that determined by the more classical approach of examining either the wavelength of the emission maximum or the fluorescence quantum yield.
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Affiliation(s)
- J J Grabowski
- Department of Chemistry, University of Pittsburgh, Pennsylvania 15260
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Erlanson-Albertsson C. Pancreatic colipase. Structural and physiological aspects. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1125:1-7. [PMID: 1567900 DOI: 10.1016/0005-2760(92)90147-n] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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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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Nemecz G, Jefferson J, Schroeder F. Polyene fatty acid interactions with recombinant intestinal and liver fatty acid-binding proteins. Spectroscopic studies. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)47347-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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14
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Cserháti T, Illés Z. Salting-Out and Salting-in Effects in the Reversed-Phase Thin-Layer Chromatography of Dansylated Amino Acids. Effect of Acids. ACTA ACUST UNITED AC 1991. [DOI: 10.1080/01483919108049631] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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McIntyre JC, Schroeder F, Behnke WD. The interaction of bile salt micelles with the dansyltyrosine derivatives of porcine colipase. Biophys Chem 1990; 38:143-54. [PMID: 2085649 DOI: 10.1016/0301-4622(90)80049-d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The interaction of bile salt micelles with the tyrosines of pancreatic colipase was assessed by steady-state and time-resolved fluorescence techniques. Dansyltyrosine fluorescence showed that Tyr-55 was located in the proposed interface recognition site. In support of this claim was a 70 nm blue shift and 4.3-fold quantum yield increase in emission spectrum due to taurodeoxycholate (TDOC) micelle-complex formation. Complex formation also caused a shift in the center of the major lifetime distribution from 11.7 to 15.1 ns, and more than doubled the polarization and anisotropy decay parameters. These data supported an earlier model of colipase-micelle binding that suggested that Tyr-55 was inserted into the interior of the TDOC micelle upon binding (J.C. McIntyre, P. Hundley and W.D. Behnke, Biochem. J. 245 (1987) 821). Identical experiments on a DNS-Tyr-59 derivative of colipase showed that Tyr-59 did not specifically interact with micelles. Moreover, acrylamide quenching data suggest an alteration in the protein environment surrounding DNS-Tyr-59 such that during complex formation, the efficiency of quenching of DNS-Tyr-59 increases.
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Affiliation(s)
- J C McIntyre
- Department of Molecular Genetics, Biochemistry and Microbiology, College of Medicine, University of Cincinnati, OH 45267
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