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Molecular mechanisms in homocystinuria: spatial arrangement of human cystathionine β-synthase
Hnízda, Aleš ; Kožich, Viktor (advisor) ; Holada, Karel (referee) ; Jiráček, Jiří (referee)
Protein misfolding is considered to be the major pathogenic mechanism in homocystinuria due to cystathionine beta-synthase (CBS) deficiency. The aim of this work was to study molecular mechanisms underlying protein misfolding of CBS mutants. Firstly, we studied spatial arrangement of normal human CBS protein. Using data from differential covalent labeling of solvent-exposed aminoacid residues, we identified interdomain contact area between the catalytic core and the regulatory domain in human CBS, and we subsequently generated the structural model of the full-length CBS. In the next step, we studied evolutionary divergence of CBS protein structures. We performed phylogenetic analysis that revealed unique spatial arrangement of CBS enzyme in nematodes; the domain architecture of CBS in Caenorhabditis elegans was studied experimentally in more detail. Finally, we determined conformational properties of a representative set of human CBS mutants that exhibited in various extent affected formation of tetramers and decreased catalytic activity. Using thermolysin-based proteolytic techniques for analysis of nine mutants expressed in E.coli, we found that an unfolded structure is a common intermediate occurring in CBS misfolding. The importance of protein unfolding for pathogenesis of CBS deficiency was...
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Chiral analysis of beta-alanyl-D,L-tyrosine and its derivatives by capillary electrophoresis with 2-hydroxypropyl-beta-cyclodextrin stereoselector
Sázelová, Petra ; Šolínová, Veronika ; Schimperková, Tereza ; Mášová, Alice ; Jiráček, Jiří ; Kašička, Václav
A new capillary electrophoretic method was developed for separation of enantiomers of antimicrobial dipeptide betha-Ala-D,L-Tyr and its derivatives using 50 mM Tris-phosphate, pH 2.50, as background electrolyte and 2-hydroxypropyl-betha-cyclodextrin at concentrations 20 – 60 mg/mL as chiral selector. In addition, association constants of complexes of the enatiomers of dipeptide betha-Ala-D,L-Tyr and its derivatives with 2-hydroxypropyl-betha-cyclodextrin chiral selector were determined.
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Capillary electrophoresis applied to analysis and characterization of mono-N-acyl-2,6-diaminopimelic acid derivatives
Vítovcová, M. ; Hlaváček, Jan ; Pícha, Jan ; Vaněk, Václav ; Jiráček, Jiří ; Kašička, Václav
Capillary zone electrophoresis and micellar electrokinetic chromatography have been employed for determination of electrophoretic purity degree, limit of detection and limit of quantification of twelve mono-Nacylated derivatives of 2,6-diaminopimelic acid (DAP). In addition, the DAP derivatives were characterized by effective electrophoretic mobilities of their cationic and anionic forms in several classical and isoelectric buffer-based background electrolytes within a broad pH range 2.18 – 8.64.
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