The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel analytical concept in the study of linear tetrapyrroles metabolic processes based on an in-depth mapping of binding sites in the structure of human serum albumin (HSA). A combination of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling methods was used for recognition of the binding site for BR, its derivatives (mesobilirubin and bilirubin ditaurate), and the products of the photo-isomerization and oxidation (lumirubin, biliverdin, and xanthobilirubic acid) on HSA. The CD spectra and fluorescent quenching of the Trp-HSA were used to calculate the binding constants. The results of the CD displacement experiments performed with hemin were interpreted together with the findings of molecular docking performed on the pigment-HSA complexes. We estimated that Z,Z-BR and its metabolic products bind on two independent binding sites. Our findings support the existence of a reversible antioxidant redox cycle for BR and explain an additional pathway of the photo-isomerization process (increase of HSA binding capacity; the excess free [unbound] BR can be converted and also bound to HSA).

• MeSH
• bilirubin analogy a deriváty   chemie   metabolismus   MeSH
• biliverdin analogy a deriváty   chemie   metabolismus   MeSH
• cirkulární dichroismus MeSH
• fluorescenční spektrometrie MeSH
• fotochemické procesy * MeSH
• kompetitivní vazba MeSH
• lidé MeSH
• ligandy MeSH
• molekulární konformace MeSH
• molekulární modely * MeSH
• oxidace-redukce MeSH
• sérový albumin chemie   metabolismus   MeSH
• simulace molekulového dockingu MeSH
• stereoizomerie MeSH
• taurin analogy a deriváty   chemie   metabolismus   MeSH
• tryptofan chemie   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A very short three-step approach to trans,trans,trans-2,5-diaryl-3,4-dimethyltetrahydrofuran lignans is reported. The carbon skeleton is assembled in a single step based on an unprecedented tandem reaction consisting of 1,2-addition of aryllithium reagents to α,β-unsaturated aldehydes, ruthenium-catalyzed redox isomerization of the resulting alkoxides to enolates and their dimerization triggered by single electron oxidation. The resulting 2,3-dialkyl-1,4-diketones form with moderate to good d/l-diastereoselectivity and are transformed to the target tetrahydrofuran lignans by reduction and diastereoselective cycloetherification.

• MeSH
• aldehydy chemická syntéza   chemie   MeSH
• biomimetika MeSH
• cyklizace MeSH
• furany chemická syntéza   chemie   MeSH
• isomerie MeSH
• katalýza MeSH
• krystalografie rentgenová MeSH
• lignany chemická syntéza   chemie   MeSH
• molekulární modely MeSH
• oxidace-redukce MeSH
• oxidační párování MeSH
• ruthenium chemie   MeSH
• techniky syntetické chemie MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• chelátory MeSH
• isomerie MeSH
• kyselina dimerkaptojantarová MeSH
• stereoizomerie MeSH
• technecium MeSH

• MeSH
• fluorescence MeSH
• Schiffovy báze analýza   chemie   MeSH
• stereoizomerie MeSH

• MeSH
• heterotaxe MeSH
• kojenec MeSH
• lidé MeSH
• mnohočetné abnormality MeSH
• novorozenec MeSH
• vrozené, dědičné a novorozenecké nemoci a abnormality MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

• MeSH
• isomerie MeSH
• nukleové kyseliny, nukleosidy a nukleotidy chemická syntéza   MeSH
• vazebná místa MeSH

Recruitment of appropriate RNA processing factors to the site of transcription is controlled by post-translational modifications of the C-terminal domain (CTD) of RNA polymerase II (RNAP II). Here, we report the solution structure of the Ser5 phosphorylated (pSer5) CTD bound to Nrd1. The structure reveals a direct recognition of pSer5 by Nrd1 that requires the cis conformation of the upstream pSer5-Pro6 peptidyl-prolyl bond of the CTD. Mutations at the complex interface diminish binding affinity and impair processing or degradation of noncoding RNAs. These findings underpin the interplay between covalent and noncovalent changes in the CTD structure that constitute the CTD code.

• MeSH
• fosforylace MeSH
• molekulární modely MeSH
• nekódující RNA metabolismus   MeSH
• prolin metabolismus   MeSH
• proteiny vázající RNA chemie   metabolismus   MeSH
• RNA-polymerasa II metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   metabolismus   MeSH
• Saccharomyces cerevisiae cytologie   enzymologie   genetika   metabolismus   MeSH
• serin metabolismus   MeSH
• terciární struktura proteinů MeSH
• vazba proteinů MeSH
• viabilita buněk MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• isomerie MeSH
• lidé MeSH
• thiepiny farmakologie   chemie   MeSH
• Check Tag
• lidé MeSH

α-Terpineol, terpinen-4-ol, and δ-terpineol, isomers of terpineol, are among the compounds that give Cinnamomum longepaniculatum leaf oil its distinguished pleasant smell. The objective of this study was to evaluate the antimicrobial activity of these three isomeric terpineols. The determination of antibacterial activity was based on the minimum inhibition concentration (MIC) and minimum bactericide concentration (MBC). Changes in time-kill curve, alkaline phosphatase (AKP), UV-absorbing material, membrane potential, and scanning electron microscopy (SEM) were measured to elucidate the possible antimicrobial mechanism. α-Terpineol, terpinen-4-ol, and δ-terpineol demonstrated good inhibitory effects against several gram-negative bacteria, particularly Shigella flexneri. MIC and MBC of α-terpineol and terpinen-4-ol were similar (0.766 mg/mL and 1.531 mg/mL, respectively) for S. flexneri, while the MIC and MBC values of δ-terpineol were 0.780 mg/mL and 3.125 mg/mL, respectively. Time-kill curves showed that the antibacterial activities of the tested compounds were in a concentration-dependent manner. Release of nucleic acids and proteins along with a decrease in membrane potential proved that α-terpineol, terpinen-4-ol, and δ-terpineol could increase the membrane permeability of Shigella flexneri. Additionally, the release of AKP suggested that the cell wall was destroyed. SEM analysis further confirmed that S. flexneri cell membranes were damaged by α-terpineol, terpinen-4-ol, and δ-terpineol. Our research suggests that these three isomeric terpineols have the potential of being used as natural antibacterial agents by destroying the cell membrane and wall, resulting in cell death. However, the specific antibacterial activity differences need further investigation.

• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• buněčná stěna účinky léků   MeSH
• gramnegativní bakterie účinky léků   MeSH
• isomerie MeSH
• listy rostlin chemie   MeSH
• membránové potenciály účinky léků   MeSH
• mikrobiální testy citlivosti MeSH
• oleje prchavé chemie   farmakologie   MeSH
• skořicovník chemie   MeSH
• terpeny chemie   farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie