Isoprenoid Quinones in an Aerobic Hyperthermophilic Archaeum Aeropyrum pernix
Fumiko NISHIDA*a, Miyuki NISHIJIMAa, Kenich MOCHIDAa, Hiroshi SANOa, Norimichi NOMURAb, Yoshihiko SAKOb, and Tadashi MARUYAMAc
a Shimizu Laboratory, Marine Biotechnology Institute, 1900 Sodeshi-cho, Shimizu-shi, Shizuoka 424, Japan
b Laboratory of Marine Microbiology, Department of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto 606-01, Japan
c Kamaishi Laboratory, Marine Biotechnology Institute, Heita, Kamaishi-shi, Iwate 026, Japan
Aeropyrum pernix is the first strictly aerobic hyperthermophile growing heterotrophically at neutral pH and at temperatures up to 100℃.
Quinones are essential components of the respiratory electron transport system of bacterial plasma membrans and have attracted attention not only in their physiological aspects but also chemotaxonomic viewpoints. While some thermophilic archaea have unique quinones such as cardariellaquinone and tricyclic quinone, the data on the distribution of the isoprenoid quinones in hyperthermophilic archaea are still fragmentary at present.
We have developed a simple and sensitive quione analysis method by using the frit-FAB LC/MS system and analyzed quinones in A. pernix. A. pernix contained demethylmenaquinones (DMKs)-6 and methionaquinones (MTKs)-6. These were the partially or fully saturated quinones with six isoprenyl units. Although DMK and MTK are the quinones found in eubacteria, the present study is the first to our knowledge to demonstrate the simultanious occurrence of DMK and MTK in archaea. So we futher investigated whether the production of DMK and MTK in this strain depends on aerobic or microaerobic conditions. Under microaerobic condition, a partially saturated menaquinone (MK)-6 appeared and a fully saturated MTK-6 decreased. On the time course, the fully saturated DMK-6 and MTK-6 appeared in initial stage of growth. We report the evidence that this strain formes DMK, MK and MTK, depending on various growth conditions.
