Conformational folding of mycobacterial methoxy- and ketomycolic acids facilitated by α-methyl trans-cyclopropane groups rather than cis-cyclopropane units
| Autor: | Kieko Horiuchi, Yukio Hitotsuyanagi, David E. Minnikin, Motoko Watanabe, Koichi Takeya, Masumi Villeneuve, Yutaka Aoyagi, Shuichi Hirono, Hiroaki Gouda, Mizuo Kawai |
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| Rok vydání: | 2013 |
| Předmět: |
Mycobacterium kansasii
chemistry.chemical_classification biology Stereochemistry Molecular Conformation Mycobacterium tuberculosis Mycobacterium avium Complex biology.organism_classification Microbiology Molecular conformation Cyclopropane Mycolic acid Folding (chemistry) chemistry.chemical_compound Mycolic Acids chemistry Molecule Computer Simulation Mycobacterium |
| Zdroj: | Microbiology. 159:2405-2415 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/mic.0.068866-0 |
| Popis: | The oxygenated long-chain mycolic acids from many mycobacteria are characterized by the presence of mid-chain cyclopropane groups, which can have either cis-configuration or trans-configuration with an adjacent methyl branch. To determine the effect of these functional groups on mycolic acid conformation, surface pressure (π) versus mean molecular area isotherms of methoxy- (MeO-) mycolic acids (MAs) from Mycobacterium kansasii, Mycobacterium tuberculosis (Mtb) Canetti and Mtb H37Ra, and of keto-MAs from Mycobacterium avium-intracellulare complex (MAC) and Mtb H37Ra were recorded and analysed. The MeO- and keto-MAs from Mtb H37Ra, containing scarcely any trans-cyclopropyl groups, apparently took no fully folded 'W-form' conformations. Keto-MA from MAC, whose trans-cyclopropyl group content is nearly 90 %, showed a very solid W-form conformation. MeO-MAs from M. kansasii and Mtb Canetti gave stable W-form conformations at lower temperatures and surface pressures and extended conformations at higher temperatures and surface pressures; their W-form conformation was not as stable as expected from their cis-cyclopropyl group content, probably because they had a wide range of constituent homologues. Energy level calculations of cis- or α-methyl trans-cyclopropane-containing model molecules and computer simulation studies confirmed the superior folding properties of the latter functional unit. The present results were compared with those of MeO- and keto-MAs from Mtb and from M. bovis Bacillus Calmette-Guérin (BCG) reported previously. Among the oxygenated MAs, those having higher trans-cyclopropane content tended to take W-form conformations more firmly, implying that the meromycolate proximal intra-chain α-methyl trans-cyclopropane groups facilitated MA folding more than cis-cyclopropane groups. |
| Databáze: | OpenAIRE |
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