Open AccessCharacterization of ammonium and methylamine transport systems in phototrophic sulfur bacteria
Author(s) -
Khatipov Emirasan A.,
Ivanovsky Ruslan N.
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07922.x
Subject(s) - methylamine , valinomycin , ammonium , sulfur , chemistry , bacteria , purple bacteria , rhodospirillales , membrane , biochemistry , biology , organic chemistry , photosynthesis , photosynthetic reaction centre , genetics
Transport of ammonium and methylamine into the cells of green sulfur bacterium Chlorobium limicola and purple sulfur bacterium Thiocapsa roseopersicina is carried out by a common transport system. This system has (for C. limicola and T. roseopersicina , respectively) pH optimum 7.0 and 7.5; V max 0.6 and 4.2 nmol min −1 (mg protein) −1 ; K m 5.9 × 10 −5 M and 1.3 × 10 −5 M, and is capable of forming 120‐ and 600‐fold methylamine gradients. The methylamine transport can be energized by the artificially imposed transmembrane K + diffusive potential and is inhibited by tetraphenylphosphonium or valinomycin and K + . The data presented indicate that methylamine transport in both studied species is exclusively driven by the membrane potential gradient (ΔΨ).