52 research outputs found

    Proteinová chemie a hmostnostní spektrometrie v biochemickém výzkumu

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    Proteinová chemie a hmotnostní spektrometrie v biochemickém výzkumu Petr Pompach Disertační práce (2006) Katedra Biochemie, Přírodovědecká Fakulta Univerzity Karlovy Abstrakt Hmotnostní spektrometrie se díky svému velmi rychlému rozvoji zařadila mezi oblíbené analytické metody nejen pro detekci malých molekul, ale i pro detekci makromolekul, jakými jsou například proteiny. V této disertační práci jsou shrnuty některé aplikace hmotnostní spektrometrie jednak pro nalezení a popsání jednotlivých proteinů v komplexních směsích, tak i aplikace pro řešení struktury proteinů a jejich postranslačních modifikací. V jednotlivých kapitolách jsou popsány poslední poznatky o analytických přístupech zahrnující separaci proteinů pomocí dvoudimenzionální elektroforézy, vysokoúčinnou separaci proteinů/peptidů na kolonách s obrácenou fází, dále potom sekvenace proteinů Edmanovým odbouráváním, atd. Jako příklad využití hmotnostní spektrometrie pro identifikaci proteinů je v této práci ukázána metoda pro nabohacení a následnou charakterizaci proteinů asociovaných s tzv. membránovými mikrodoménami. Pro řešení struktury proteinů pomocí hmotnostní spektrometrie se využívá její spojení s metodami proteinové chemie, konktrétně reakcí proteinů s tzv. zesíťovacími činidly. Délka raménka zesíťovacího činidla určuje poté vzdálenost...Protein chemistry and mass spectrometry in biochemical research Petr Pompach Ph. D. Thesis (2006) Department of Biochemistry, Faculty of Science, Charles University Abstract Mass spectrometry is a fast and growing analytical approach frequently used not only for detection of small molecules, but also for detection and characterization of macromolecules such as proteins and peptides. The presented PhD thesis summarizes several mass spectrometric applications for identification and characterization of proteins in complex biological matrices, applications for determination of protein structures and characterization of posttranslational modifications. Analytical methods are described in different chapters and include: separation of protein/peptides by two dimensional SDS electrophoresis, separation of proteins/peptides by high performance liquid chromatography, protein sequencing by Edman degradation, etc. As an example of the usage of mass spectrometry for identification of proteins, a method for enrichment followed by characterization of proteins associated with membrane microdomains is shown. For determination of proteins structure by mass spectrometry, chemical cross-linking is usually used. The length of spacer arm of the cross-linker determines the distance constrains between modified amino acids. The...Katedra biochemieDepartment of BiochemistryFaculty of SciencePřírodovědecká fakult

    Protein chemistry and mass spectrometry in biochemical research

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    Protein chemistry and mass spectrometry in biochemicul research Petr Pompach Ph. D. Thesis Department of Biochemistry Faculty of Science Charles University Supervisor: Doc. RNDr. Karel Bezouška, CSc. Prague 2006 tEia*iiitg;;tiBiÉ (n OO oO O\ O\ C.l C.l .+ : : : : :ÉGlc.l c.: Ý l.) a z t-r (J Fl E) lra J a U z a Fr tl5 a Fr zr\J) alai P.: ai a - Lr o L d a (|i iť r h t) o() r a a q C) ! - H F (n F íi a o) O a X, o >. C) o .l I +i oL o -O o o l.r U) N z oo - O o I L a Li +i vi ol Ei!t ,ql -l E 3a (n z E F a F z F z U pg ť: šé3; Ei ĚEáE€EÉEáiz E ÉĚ E Ě s E ; u ; ó =-E5Ě:gd:'i = t Ei giĚg;;:1lV)iĚggĚgEsáEĚi* E Ě=;Éía:š;Éť E É!řěEEEFgg : ií€gáŤÉ5 ž:::š;;i : zi:€ i=ts€ĚiĚišĚÉiš;š5ĚiE.:. = = € .T ŽlĚE g;tjíigggřEE iuEái E :É€šáĚ g;iÉ{Ě;ítÉÉF€Ě E iĚĚĚi ; š;šš!iiE řě E ši gE ig Ý E giĚE šgig;išiš::gígFĚi+g s E *'suĚšěĚ Ěie *Ěá, uE trE s'' -k*-=a.*:.* g: EPE€'šEEř€9 ěÍ.E ;š e::E;;áe;iÉgřšiE řĚt.E*EeE=*eE=[:gř.v :IEF€=áfrE;='2E-ď ?! : g"HEu.:i=ĚE€;ÉE€ř€ Eš,*éEě9t.F;EE.Ě., ťiEEEE*ě:iiEĚgĚ:Éžáx;šš ř 5šEtsť uE.E.= e *n á:; € žEř: € ÉE.: i= ř-g p; i ĚĚ;: € i íEĚ = Hi;2E É*Ě u, Ě y ?' : 6 ě ř ; fij .: .c F=E;-sg&,Ě7Éď€3E€€ -i€E.E =:Í E=bÉ::ň !B:,: E t šáč š 3e = Ě l E ř f L Ei:í:9:*q;€gq3:;:.E: ťšÉI: Ě i ?E Ě ; Éi É.EE E EEE :!rEě45BEE EE.= €Eě íEEra-vĚ=3ň €.E3 iillťlgtššgtgi;g;ggiĚš; iáágá9 i;Eˇ:E;Eaˊs;t;Eˊ*i;Ě:E; -Eás;t;É \o Ěi gi...Protein chemistry and mass spectrometry in biochemicul research Petr Pompach Ph. D. Thesis Department of Biochemistry Faculty of Science Charles University Supervisor: Doc. RNDr. Karel Bezouška, CSc. Prague 2006 tEia*iiitg;;tiBiÉ (n OO oO O\ O\ C.l C.l .+ : : : : :ÉGlc.l c.: Ý l.) a z t-r (J Fl E) lra J a U z a Fr tl5 a Fr zr\J) alai P.: ai a - Lr o L d a (|i iť r h t) o() r a a q C) ! - H F (n F íi a o) O a X, o >. C) o .l I +i oL o -O o o l.r U) N z oo - O o I L a Li +i vi ol Ei!t ,ql -l E 3a (n z E F a F z F z U pg ť: šé3; Ei ĚEáE€EÉEáiz E ÉĚ E Ě s E ; u ; ó =-E5Ě:gd:'i = t Ei giĚg;;:1lV)iĚggĚgEsáEĚi* E Ě=;Éía:š;Éť E É!řěEEEFgg : ií€gáŤÉ5 ž:::š;;i : zi:€ i=ts€ĚiĚišĚÉiš;š5ĚiE.:. = = € .T ŽlĚE g;tjíigggřEE iuEái E :É€šáĚ g;iÉ{Ě;ítÉÉF€Ě E iĚĚĚi ; š;šš!iiE řě E ši gE ig Ý E giĚE šgig;išiš::gígFĚi+g s E *'suĚšěĚ Ěie *Ěá, uE trE s'' -k*-=a.*:.* g: EPE€'šEEř€9 ěÍ.E ;š e::E;;áe;iÉgřšiE řĚt.E*EeE=*eE=[:gř.v :IEF€=áfrE;='2E-ď ?! : g"HEu.:i=ĚE€;ÉE€ř€ Eš,*éEě9t.F;EE.Ě., ťiEEEE*ě:iiEĚgĚ:Éžáx;šš ř 5šEtsť uE.E.= e *n á:; € žEř: € ÉE.: i= ř-g p; i ĚĚ;: € i íEĚ = Hi;2E É*Ě u, Ě y ?' : 6 ě ř ; fij .: .c F=E;-sg&,Ě7Éď€3E€€ -i€E.E =:Í E=bÉ::ň !B:,: E t šáč š 3e = Ě l E ř f L Ei:í:9:*q;€gq3:;:.E: ťšÉI: Ě i ?E Ě ; Éi É.EE E EEE :!rEě45BEE EE.= €Eě íEEra-vĚ=3ň €.E3 iillťlgtššgtgi;g;ggiĚš; iáágá9 i;Eˇ:E;Eaˊs;t;Eˊ*i;Ě:E; -Eás;t;É \o Ěi gi...Department of BiochemistryKatedra biochemieFaculty of SciencePřírodovědecká fakult

    Identification of enzymes oxidizing the tyrosine kinase inhibitor cabozantinib: Cabozantinib is predominantly oxidized by CYP3A4 and its oxidation is stimulated by cyt b5 activity

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    Herein, the in vitro metabolism of tyrosine kinase inhibitor cabozantinib, the drug used for the treatment of metastatic medullary thyroid cancer and advanced renal cell carcinoma, was studied using hepatic microsomal samples of different human donors, human recombinant cytochromes P450 (CYPs), flavin-containing mono-oxygenases (FMOs) and aldehyde oxidase. After incubation with human microsomes, three metabolites, namely cabozantinib N-oxide, desmethyl cabozantinib and monohydroxy cabozantinib, were detected. Significant correlations were found between CYP3A4 activity and generation of all metabolites. The privileged role of CYP3A4 was further confirmed by examining the effect of CYP inhibitors and by human recombinant enzymes. Only four of all tested human recombinant cytochrome P450 were able to oxidize cabozantinib, and CYP3A4 exhibited the most efficient activity. Importantly, cytochrome b(5) (cyt b(5)) stimulates the CYP3A4-catalyzed formation of cabozantinib metabolites. In addition, cyt b(5) also stimulates the activity of CYP3A5, whereas two other enzymes, CYP1A1 and 1B1, were not affected by cyt b(5). Since CYP3A4 exhibits high expression in the human liver and was found to be the most efficient enzyme in cabozantinib oxidation, we examined the kinetics of this oxidation. The present study provides substantial insights into the metabolism of cabozantinib and brings novel findings related to cabozantinib pharmacokinetics towards possible utilization in personalized medicine

    Development of a PNGase Rc column for online deglycosylation of complex glycoproteins during HDX-MS

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    Protein glycosylation is one of the most common PTMs and many cell surface receptors, extracellular proteins, and biopharmaceuticals are glycosylated. However, HDX-MS analysis of such important glycoproteins has so far been limited by difficulties in determining the HDX of the protein segments that contain glycans. We have developed a column containing immobilized PNGase Rc (from Rudaea cellulosilytica) that can readily be implemented into a conventional HDX-MS setup to allow improved analysis of glycoproteins. We show that HDX-MS with the PNGase Rc column enables efficient online removal of N-linked glycans and the determination of the HDX of glycosylated regions in several complex glycoproteins. Additionally, we use the PNGase Rc column to perform a comprehensive HDX-MS mapping of the binding epitope of a mAb to c-Met, a complex glycoprotein drug target. Importantly, the column retains high activity in the presence of common quench-buffer additives like TCEP and urea and performed consistent across 114 days of extensive use. Overall, our work shows that HDX-MS with the integrated PNGase Rc column can enable fast and efficient online deglycosylation at harsh quench conditions to provide comprehensive analysis of complex glycoproteins

    An Integrative Structural Biology Analysis of Von Willebrand Factor Binding and Processing by ADAMTS-13 in Solution

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    Von Willebrand Factor (vWF), a 300-kDa plasma protein key to homeostasis, is cleaved at a single site by multi-domain metallopeptidase ADAMTS-13. vWF is the only known substrate of this peptidase, which circulates in a latent form and becomes allosterically activated by substrate binding. Herein, we characterised the complex formed by a competent peptidase construct (AD13-MDTCS) comprising metallopeptidase (M), disintegrin-like (D), thrombospondin (T), cysteine-rich (C), and spacer (S) domains, with a 73-residue functionally relevant vWF-peptide, using nine complementary techniques. Pull-down assays, gel electrophoresis, and surface plasmon resonance revealed tight binding with sub-micromolar affinity. Cross-linking mass spectrometry with four reagents showed that, within the peptidase, domain D approaches M, C, and S. S is positioned close to M and C, and the peptide contacts all domains. Hydrogen/deuterium exchange mass spectrometry revealed strong and weak protection for C/D and M/S, respectively. Structural analysis by multi-angle laser light scattering and small-angle X-ray scattering in solution revealed that the enzyme adopted highly flexible unbound, latent structures and peptide-bound, active structures that differed from the AD13-MDTCS crystal structure. Moreover, the peptide behaved like a self-avoiding random chain. We integrated the results with computational approaches, derived an ensemble of structures that collectively satisfied all experimental restraints, and discussed the functional implications. The interaction conforms to a ‘fuzzy complex’ that follows a ‘dynamic zipper’ mechanism involving numerous reversible, weak but additive interactions that result in strong binding and cleavage. Our findings contribute to illuminating the biochemistry of the vWF:ADAMTS-13 axis.This study was supported in part by grants from Spanish, French, Danish and Catalan public and private bodies (grant/fellowship references PID2019-107725RG-I00, BES-2015-074583, ANR-10-LABX-12-01, 6108-00031B, 8022-00385B, LF18039, NNF18OC0032724, Novo Nordisk Foundation “Bio-MS”, 2017SGR3 and Fundació “La Marató de TV3” 201815). This work was also supported by EPICS-XS, project 823839, funded by the Horizon 2020 programme of the European Union. The CBS is a member of France-BioImaging (FBI) and the French Infrastructure for Integrated Structural Biology (FRISBI), which are national infrastructures supported by the French National Research Agency (grants ANR-10-INBS-04-01 and ANR-10-INBS-05, respectively). Finally, we acknowledge the Structural Mass Spectrometry Unit of CIISB, an Instruct-CZ Centre, which was supported by MEYS CR (LM2018127)

    Structure of the dimeric N-glycosylated form of fungal β-N-acetylhexosaminidase revealed by computer modeling, vibrational spectroscopy, and biochemical studies

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    <p>Abstract</p> <p>Background</p> <p>Fungal β-<it>N</it>-acetylhexosaminidases catalyze the hydrolysis of chitobiose into its constituent monosaccharides. These enzymes are physiologically important during the life cycle of the fungus for the formation of septa, germ tubes and fruit-bodies. Crystal structures are known for two monomeric bacterial enzymes and the dimeric human lysosomal β-<it>N</it>-acetylhexosaminidase. The fungal β-<it>N</it>-acetylhexosaminidases are robust enzymes commonly used in chemoenzymatic syntheses of oligosaccharides. The enzyme from <it>Aspergillus oryzae </it>was purified and its sequence was determined.</p> <p>Results</p> <p>The complete primary structure of the fungal β-<it>N</it>-acetylhexosaminidase from <it>Aspergillus oryzae </it>CCF1066 was used to construct molecular models of the catalytic subunit of the enzyme, the enzyme dimer, and the <it>N</it>-glycosylated dimer. Experimental data were obtained from infrared and Raman spectroscopy, and biochemical studies of the native and deglycosylated enzyme, and are in good agreement with the models. Enzyme deglycosylated under native conditions displays identical kinetic parameters but is significantly less stable in acidic conditions, consistent with model predictions. The molecular model of the deglycosylated enzyme was solvated and a molecular dynamics simulation was run over 20 ns. The molecular model is able to bind the natural substrate – chitobiose with a stable value of binding energy during the molecular dynamics simulation.</p> <p>Conclusion</p> <p>Whereas the intracellular bacterial β-<it>N</it>-acetylhexosaminidases are monomeric, the extracellular secreted enzymes of fungi and humans occur as dimers. Dimerization of the fungal β-<it>N</it>-acetylhexosaminidase appears to be a reversible process that is strictly pH dependent. Oligosaccharide moieties may also participate in the dimerization process that might represent a unique feature of the exclusively extracellular enzymes. Deglycosylation had only limited effect on enzyme activity, but it significantly affected enzyme stability in acidic conditions. Dimerization and <it>N</it>-glycosylation are the enzyme's strategy for catalytic subunit stabilization. The disulfide bridge that connects Cys<sup>448 </sup>with Cys<sup>483 </sup>stabilizes a hinge region in a flexible loop close to the active site, which is an exclusive feature of the fungal enzymes, neither present in bacterial nor mammalian structures. This loop may play the role of a substrate binding site lid, anchored by a disulphide bridge that prevents the substrate binding site from being influenced by the flexible motion of the loop.</p

    Důležitost štěpení glykosylovaných propeptidů: například beta-N-acetylhexosaminidázy

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    Fungal Bta-N-acetylhexosaminidases are secreted anzymes that hydrolyze chitobiose into monosaccharides

    Protein chemistry and mass spectrometry in biochemical research

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    Protein chemistry and mass spectrometry in biochemicul research Petr Pompach Ph. D. Thesis Department of Biochemistry Faculty of Science Charles University Supervisor: Doc. RNDr. Karel Bezouška, CSc. Prague 2006 tEia*iiitg;;tiBiÉ (n OO oO O\ O\ C.l C.l .+ : : : : :ÉGlc.l c.: Ý l.) a z t-r (J Fl E) lra J a U z a Fr tl5 a Fr zr\J) alai P.: ai a - Lr o L d a (|i iť r h t) o() r a a q C) ! - H F (n F íi a o) O a X, o >. C) o .l I +i oL o -O o o l.r U) N z oo - O o I L a Li +i vi ol Ei!t ,ql -l E 3a (n z E F a F z F z U pg ť: šé3; Ei ĚEaˊEEEˊEaˊizEEˊEˇEEˇsE;u;oˊ=E5Eˇ:gd:i=tEigiEˇg;;:1lV)iEˇggEˇgEsaˊEEˇiEEˇ=;Eˊıˊa:sˇ;EˊtˇEEˊ!rˇeˇEEEFgg:iıˊgaˊTˇEˊ5zˇ:::sˇ;;i:zi:i=tsEˇiEˇisˇEˇEˊisˇ;sˇ5EˇiE.:.==.TZˇlEˇEg;táE€EÉEáiz E ÉĚ E Ě s E ; u ; ó =-E5Ě:gd:'i = t Ei giĚg;;:1lV)iĚggĚgEsáEĚi* E Ě=;Éía:š;Éť E É!řěEEEFgg : ií€gáŤÉ5 ž:::š;;i : zi:€ i=ts€ĚiĚišĚÉiš;š5ĚiE.:. = = € .T ŽlĚE g;tjíigggřEE iuEái E :É€šáĚ g;iÉ{Ě;ítÉÉF€Ě E iĚĚĚi ; š;šš!iiE řě E ši gE ig Ý E giĚE šgig;išiš::gígFĚi+g s E *'suĚšěĚ Ěie *Ěá, uE trE s'' -k*-=a.*:.* g: EPE€'šEEř€9 ěÍ.E ;š e::E;;áe;iÉgřšiE řĚt.E*EeE=*eE=[:gř.v :IEF€=áfrE;='2E-ď ?! : g"HEu.:i=ĚE€;ÉE€ř€ Eš,*éEě9t.F;EE.Ě., ťiEEEE*ě:iiEĚgĚ:Éžáx;šš ř 5šEtsť uE.E.= e *n á:; € žEř: € ÉE.: i= ř-g p; i ĚĚ;: € i íEĚ = Hi;2E É*Ě u, Ě y ?' : 6 ě ř ; fij .: .c F=E;-sg&,Ě7Éď€3E€€ -i€E.E =:Í E=bÉ::ň !B:,: E t šáč š 3e = Ě l E ř f L Ei:í:9:*q;€gq3:;:.E: ťšÉI: Ě i ?E Ě ; Éi É.EE E EEE :!rEě45BEE EE.= €Eě íEEra-vĚ=3ň €.E3 iillťlgtššgtgi;g;ggiĚš; iáágá9 i;Eˇ:E;Eaˊs;t;Eˊ*i;Ě:E; -Eás;t;É \o Ěi gi..
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