Roles of α-methyl trans-cyclopropane groups in behavior of mixed mycolic acid monolayers
| Autor: | Hiroki Noguchi, Masumi Villeneuve |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Cyclopropanes
Langmuir Molar concentration 030303 biophysics Biophysics Mole fraction Biochemistry Cyclopropane Mycolic acid Mycobacterium 03 medical and health sciences chemistry.chemical_compound Monolayer Pressure Elastic modulus Phase diagram chemistry.chemical_classification 0303 health sciences 030306 microbiology Temperature Cell Biology Elasticity Molecular Weight Crystallography chemistry Mycolic Acids lipids (amino acids peptides and proteins) |
| Zdroj: | Biochimica et biophysica acta. Biomembranes. 1861(2) |
| ISSN: | 1879-2642 |
| Popis: | Mixed Langmuir films of type 1 alpha-(α-) and keto-mycolic acids (MAs) were investigated to understand the roles of α-methyl trans-cyclopropane containing keto-MA in determining the physical and chemical properties of the monolayers. Surface pressure (π) vs. mean molecular area (A) isotherms were measured at constant mole fractions defined as the ratio of the keto-MA molarity to the total molarity of α-MA and keto-MA (Xketo) at 25 °C and 37 °C. A and the elastic modulus (E) of the mixed monolayer were compared for different Xketo at fixed π values. In keto-MA rich monolayers, A values were much larger than values of the combined areas of α-MA and keto-MA, while the E values were close to those of solid keto-MA monolayers. A and E were also plotted against the mole fraction of α-methyl trans-cyclopropane containing keto-MA, which showed that the α-methyl trans-cyclopropane group stabilized the W-form conformation of mycolic acids in monolayers, and rendered them solid state. Furthermore, a comparison of the experimental results and the α-methyl trans-cyclopropane content in cell-wall MAs from various strains indicated that the ratio of trans-cyclopropane content was important in determining the nature of the mixed MA layer. |
| Databáze: | OpenAIRE |
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