title: Cyclopropane-ring formation in the acyl groups of chlorosome glycolipids is crucial for acid resistance of green bacterial antenna systems.
abstract: Green photosynthetic bacteria have unique light-harvesting antenna systems called chlorosomes. Chlorobaculum tepidum, a model organism of the bacteria, biosynthesized monogalactosyl- and rhamnosylgalactosyldiacylglycerides possessing a methylene-bridged palmitoleyl group characterized by a cis-substituted cyclopropane ring as the dominant glycolipids of its chlorosome surface. The formation of the cyclopropane ring was chemically inhibited by supplementation of sinefungin, an analog of S-adenosyl-L-methionine, into the bacterial cultivation. The presence of the cyclopropane ring reinforced acid resistance of the light-harvesting chlorosomes and suppressed acidic demetalation (pheophytinization) of bacteriochlorophyll-c pigments constructing the core part of chlorosomes. The ring-formation would represent direct and post-synthetic modifications of chlorosome membrane properties and was tolerant of acidic environments.
authors.affiliation: Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Mizoguchi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsukatani
authors.forename: Jiro
authors.initials: J
authors.lastname: Harada
authors.forename: Shin
authors.initials: S
authors.lastname: Takasaki
authors.forename: Taichi
authors.initials: T
authors.lastname: Yoshitomi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tamiaki
mesh_terms: D000215:Acylation; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001429:Bacteriochlorophylls / Q000737:chemistry / Q000378:metabolism*; D019414:Chlorobi / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism*; D003521:Cyclopropanes / Q000737:chemistry / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D006017:Glycolipids / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D003521:Cyclopropanes; D005227:Fatty Acids; D006017:Glycolipids; C028775:cyclopropane fatty acids; C002084:bacteriochlorophyll c