- Collision-induced dissociative chemical cross-linking reagent for protein structure characterization: Applied Edman chemistry in the gas phase
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Chemical cross-linking combined with a subsequent enzymatic digestion andmass spectrometric analysis of the created crosslinked products presents an alternative approach to assess low-resolution protein structures and to gain insight into protein interfaces. In this contribution, we report the design of an innovative cross-linker based on Edman degradation chemistry, which leads to the formation of indicative mass shifted fragment ions and constant neutral losses (CNLs) in electrospray ionization (ESI)-tandem-mass spectrometry (MS/MS) product ion mass spectra, allowing an unambiguous identification of cross-linked peptides. Moreover, the characteristic neutral loss reactions facilitate automated analysis by multiple reaction monitoring suited for high throughput studies with good sensitivity and selectivity. The functioning of the novel cross-linker relies on the presence of a highly nucleophilic sulfur in a thiourea moiety, safeguarding for effective intramolecular attack leading to predictive and preferred cleavage of a glycyl-prolyl amide bond. Our innovative analytical concept and the versatile applicability of the collision-induced dissociative chemical cross-linking reagent are exemplified for substance P, luteinizing hormone releasing hormone LHRH and lysozyme. The novel cross-linker is expected to have a broad range of applications for probing protein tertiary structures and for investigating protein-protein interactions. Copyright
- Dreiocker, Frank,Mueller, Mathias Q.,Sinz, Andrea,Schaefer, Mathias
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- A Chemical Model for the Activation of Pyruvate-Formate-Lyase
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A chemical model is described for the activation of the carbon-centred radical-based enzyme, pyruvate-formate-lyase.The feasibility of a 5'-deoxyadensyl radical abstracting a hydrigen atom from C-2 of a peptideglycine residue has been demonstrated in an intramolecular process.
- Baldwin, Jack E.,Brown, David,Scudder, Paul H.,Wood, Mark E.
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- A new benzotriazole-mediated stereoflexible gateway to hetero-2,5- diketopiperazines
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Open chain Cbz-L-aa1-L-Pro-Bt (Bt=benzotriazole) sequences were converted into either the corresponding trans- or cis-fused 2,5- diketopiperazines (DKPs) depending on the reaction conditions. Thermodynamic tandem cyclization/epimerization afforded selectively the corresponding trans-DKPs (69-75%). Complementarily, tandem deprotection/cyclization led to the cis-DKPs (65-72%). A representative set of proline-containing cis- and trans-DKPs has been prepared. A mechanistic investigation, based on chiral HPLC, kinetics, and computational studies enabled a rationalization of the results. Stereoflexible route to DKPs: A convenient, versatile, and flexible benzotriazole-mediated methodology for the synthesis of proline-containing hetero-2,5-diketopiperazines (DKPs) is reported. Depending on the reaction conditions, either cis- or trans-configured DKPs were obtained starting from the same inexpensive l,l-dipeptidoyl benzotriazole key intermediate (see scheme). Kinetics, chiral HPLC, and computational studies forged a background for mechanistic rationalization. Copyright
- Monbaliu, Jean-Christophe M.,Hansen, Finn K.,Beagle, Lucas K.,Panzner, Matthew J.,Steel, Peter J.,Todadze, Ekaterina,Stevens, Christian V.,Katritzky, Alan R.
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supporting information; experimental part
p. 2632 - 2638
(2012/04/17)
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- Inhibition of prolyl oligopeptidase with a synthetic unnatural dipeptide
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A new inhibitor, containing a linked proline-piperidine structure, for the enzyme prolyl oligopeptidase (POP) has been synthesised and demonstrated to bind covalently with the enzyme at the active site. This provides evidence that covalent inhibitors of P
- Racys, Daugirdas Tomas,Rea, Dean,Fueloep, Vilmos,Wills, Martin
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supporting information; experimental part
p. 4775 - 4782
(2010/08/22)
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- Use of 'click chemistry' for the synthesis of tetrazole-containing analogues of the neuroprotective agent glycyl-L-prolyl-L-glutamic acid
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Tetrazole-containing analogues of glycyl-L-prolyl-L-glutamic acid (GPE) were prepared by coupling of Cbz-glycyl-L-proline with tetrazole-containing glutamic acids followed by hydrogenation of the resultant tripeptide. Synthesis of the tetrazole-containing glutamic acids involved 1,3-dipolar cycloaddition of sodium azide to nitrile derivatives of the corresponding glutamic acids. Georg Thieme Verlag Stuttgart.
- Hung, Kuo-Yuan,Harris, Paul W. R.,Brimble, Margaret A.
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scheme or table
p. 1233 - 1236
(2009/09/06)
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- Efficient peptide coupling involving sterically hindered amino acids
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(Chemical Equation Presented) Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles with amino acids, wherein at least one of the components was sterically hindered, to provide compounds 3a-e, (3c +3 c′), 5a-d, (5a + 5a′), 6a-c, (6b + 6b′), 8a-c, 9a-e, 10a-d, and (10a + 10a′) in isolated yields of 41-95% with complete retention of chirality as evidenced by NMR and HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of sterically hindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixtures or racemates; compound numbers without brackets represent enantiomers.)
- Katritzky, Alan R.,Todadze, Ekaterina,Angrish, Parul,Draghici, Bogdan
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p. 5794 - 5801
(2008/02/09)
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- Synthesis and neuroprotective activity of analogues of glycyl-L-prolyl-L- glutamic acid (GPE) modified at the α-carboxylic acid
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The synthesis of nine GPE* analogues, wherein the α-carboxylic acid group of glutamic acid has been modified, is described by coupling readily accessible N-benzyloxycarbonyl-glycyl-l-proline 2 with various analogues of glutamic acid. Pharmacological evaluation of the novel compounds was undertaken to further understand the role of the glutamate residue on the observed neuroprotective properties of the endogenous tripeptide GPE.
- Trotter, Nicholas S.,Brimble, Margaret A.,Harris, Paul W.R.,Callis, David J.,Sieg, Frank
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p. 501 - 517
(2007/10/03)
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- Conformational analysis of β-turn structure in tetrapeptides containing proline or proline analogs
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In order to evaluate the influence of cyclic secondary amino acids on the stability of β-turn structure, we have prepared Ac-Gly-L-Xxx-L-Leu-Gly-N(CH3)2 (Xxx = Aze, 4-membered ring: 1, Xxx = Pro, 5-membered ring: 2, Xxx = Pip, 6-membered ring: 3). The NOE cross peaks that support β-turn structure were observed in 1-3. The NOE cross peak between both terminals of the synthetic peptides, however, was observed only in the NOESY spectra of 2. This result indicates that 5-membered ring side chain in proline plays a very important role in the formation of β-hairpin structure.
- Hayashi, Takashi,Asai, Tomohito,Ogoshi, Hisanobu
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p. 3039 - 3042
(2007/10/03)
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- Amino acids and peptides. XVI. Synthesis of N-terminal tetrapeptide analogs of fibrin α-chain and their inhibitory effects on fibrinogen/thrombin clotting
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N-Terminal tetrapeptide analogs of fibrin α-chain were synthesized by the solution method using a new active ester, the ester of the oxime of p-nitroacetophenone, and by the solid-phase method. Their inhibitory effects on fibrinogen/thrombin clotting were examined. Of the synthetic peptides, amide analogs of Gly-Pro-Arg-Pro exhibited a more potent inhibitory effect.
- Kawasaki,Hirase,Miyano,Tsuji,Iwamoto
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p. 3253 - 3260
(2007/10/02)
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- SYNTHESIS OF A NEW CYCLIC ANALOGUE OF LULIBERIN
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A new cyclic analogue of luliberin possessing the capacity for stimulating ovulation in sexually mature and infantile rate and also exhibiting a pronounced prolongation of its influence on a number of behavioral reactions of animals has been synthesized.
- Nikolaev, S. V.,Burov, S. V.,Bakharev, V. D.,Makusheva, V. P.,Korkhov, V. V.
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p. 686 - 690
(2007/10/02)
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- POST-PROLINE ENDOPEPTIDASE. PARTIAL PURIFICATION AND CHARACTERIZATION OF THE ENZYME FROM PIG KIDNEYS
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Post-proline endopeptidase was isolated from pig kidneys and partially purified.The procedure consisted of fractionation with ammonium sulphate, ion exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-200 and rechromatography on DEAE-Sephadex A-50.The preparation had 55 times higher specific activity than the crude extract and did not contain any contaminating enzymic activities.The enzyme cleaved a number of proline-containing peptides and was strictly specific in catalyzing the hydrolysis of the peptide bond on the carboxyl side of the proline residue.The optimum pH for the hydrolysis of the synthetic peptides benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide and benzyloxycarbonyl-glycyl-proline β-naphthylamide was 7.8-8.0 and, in the case of benzyloxycarbonylglycyl-proline p-nitroanilide, 7.2 to 7.5.For the hydrolysis of the tetrapeptide benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide, the Km value of 75 μmol l-1 was obtained.
- Hauzer, Karel,Servitova, Linda,Barth, Tomislav,Jost, Karel
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p. 1139 - 1148
(2007/10/02)
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