In FoF1-ATP synthase, proton translocation through Fo drives rotation of the c-subunit oligomeric ring relative to the a-subunit. Recent studies suggest that in each step of the rotation, key glutamic acid residues in different c-subunits contribute to proton release to and proton uptake from the a-subunit. However, no studies have demonstrated cooperativity among c-subunits toward FoF1-ATP synthase activity. Here, we addressed this using Bacillus PS3 ATP synthase harboring a c-ring with various combinations of wild-type and cE56D, enabled by genetically fused single-chain c-ring. ATP synthesis and proton pump activities were decreased by a single cE56D mutation and further decreased by double cE56D mutations. Moreover, activity further decreased as the two mutation sites were separated, indicating cooperation among c-subunits. Similar results were obtained for proton transfer-coupled molecular simulations. The simulations revealed that prolonged proton uptake in mutated c-subunits is shared between two c-subunits, explaining the cooperation observed in biochemical assays.

In FoF1-ATP synthase, proton translocation through Fo drives rotation of the c-subunit oligomeric ring relative to the a-subunit. Recent studies suggest that in each step of the rotation, key glutamic acid residues in different c-subunits contribute to proton release to and proton uptake from the a-subunit. However, no studies have demonstrated cooperativity among c-subunits toward FoF1-ATP synthase activity. Here, we addressed this using Bacillus PS3 ATP synthase harboring c-ring with various combinations of wild-type and cE56D, enabled by genetically fused single-chain c-ring. ATP synthesis and proton pump activities were significantly decreased by a single cE56D mutation and further decreased by double cE56D mutations. Moreover, activity further decreased as the two mutation sites were separated, indicating cooperation among c-subunits. Similar results were obtained for proton transfer-coupled molecular simulations. Simulations revealed that prolonged proton uptake in mutated c-subunits is shared between two c-subunits, explaining the cooperation observed in biochemical assays.

No abstract

No abstract

The purpose of this study is to investigate the formation of seaweed bed substrata using different sizes of Ferromanganese slag and Ferromanganese slag block in the sea area and by comparing them with the surrounding natural seaweed bed. We were unable to confirm any changes in pH or manganese concentration in seawater as a result of using FMS and FMSB. Small seaweed such as Hypnea grew five months after the material was set up. After 17 months, Sargassum horneri, Myagropsis myagroides, Undaria pinnatifida, and Ecklonia kurome grew on FMS, whereas S. horneri, Sargassum piluliferum, and Ecklonia kurome grew on FMSB. The vegetation transition progressed from undergrowth seaweed to large seaweed. About one year after the installation of the FMS and FMSB substrata, there was no significant difference in the number of seaweed species that grew on FMS and FMSB and the nearby natural seaweed bed. However, there was a small difference in the seaweed biomass between the FMS (30-75 mm) and the surrounding natural seaweed bed. We found that when using smaller material, FMS (30-75 mm) has higher seaweed biomass except in November 2017. By installing FMS and FMSB seaweed beds, we were able to confirm that the gathering fish are similar to those that gather around the nearby natural seaweed bed, but we were unable to confirm the relationship between seaweed biomass, material size, and fish density.