Over-expression of cbaAB genes of Bacillus stearothermophilus produces a two-subunit SoxB-type cytochrome c oxidase with proton pumping activity

AbstractWe constructed expression plasmids containing cbaAB, the structural genes for the two-subunit cytochrome bo3-type cytochrome c oxidase (SoxB type) recently isolated from a Gram-positive thermophile Bacillus stearothermophilus.B. stearothermophilus cells transformed with the plasmids over-expressed an enzymatically active bo3-type cytochrome c oxidase protein composed of the two subunits, while the transformed Escherichia coli cells produced an inactive protein composed of subunit I without subunit II. The oxidase over-expressed in B. stearothermophilus was solubilized and purified. The oxidase contained protoheme IX and heme O, as the main low-spin heme and the high-spin heme, respectively. Analysis of the substrate specificity indicated that the high-affinity site is very specific for cytochrome c-551, a cytochrome c that is a membrane-bound lipoprotein of thermophilic Bacillus. The purified enzyme reconstituted into liposomal vesicles with cytochrome c-551 showed H+ pumping activity, although the efficiency was lower than those of cytochrome aa3-type oxidases belonging to the SoxM-type

(2,7-Dimethoxy­naphthalene-1,8-di­yl)bis­(4-fluoro­benzo­yl)dimethanone

The title compound, C26H18F2O4, is a naphthalene derivative in which the two aroyl groups at the 1- and 8-positions (peri positions) are anti to each other. There is an appreciable difference in the dihedral angles between the naphthalene ring system and the two benzene rings [66.88 (7)° and 88.09 (6)°]. In the crystal, weak C—H⋯O inter­actions involving one of the carbonyl groups and an aromatic C—H group ortho to the F atom seem to stabilize the packing of the mol­ecules

2,7-Bis(4-acetyl­phen­oxy)naphthalene

The title compound, C26H20O4, has an asymmetrical conformation at 193 K. The 4-acetyl­phenyl groups are twisted away from the the naphthalene ring system, with one benzene ring turned towards the 1-position of the naphthalene ring and the other benzene ring turned towards the 6-position. The inter­planar angles between the mean planes of the benzene rings and the naphthalene ring system are 68.71 (6) and 74.01 (6)°. The structure displays C—H⋯O hydrogen bonding and π–π stacking inter­actions [centroid–centroid and interplanar distances are 3.5938 (9) and 3.517 Å, respectively]

Tetra­methyl­ammonium dihydrogen phosphate hemihydrate

In the crystal structure of the title compound, C4H12N+·H2PO4 −·0.5H2O, the anions form an infinite hydrogen-bonded chain along the [10] direction. The anion chains are connected by water mol­ecules, which lie on crystallographic twofold rotation axes, through O—H⋯O hydrogen bonds. These hydrogen bonds are almost perpendicular to the other hydrogen bonds which create an assembled structure of anions. In addition, C—H⋯O hydrogen bonds between anions and cations are observed

3-(2,3,5,6,7,8-Hexahydro-1H-cyclo­penta­[b]quinolin-9-yl)-1,5-bis­(4-methoxy­phen­yl)biuret

Ipidacrine (2,3,5,6,7,8-hexa­hydro-1H-cyclo­penta­[b]quinolin-9-amine) was reacted with 4-methoxy­phenyl isocyanate to give the title compound, C28H30N4O4. An intra­molecular N—H⋯O hydrogen bond results in an essentially planar [r.m.s. deviation from the mean plane is 0.126 (1) Å] conformation for the biuret unit. The central ring of the quinoline unit is twisted by 78.2 (1)° with respect to the biuret mean plane, whereas the two 4-methoxy­benzene rings are twisted out of this plane by 24.3 (1)° and 48.5 (1)°, resulting in an overall propeller-like structure. An inter­molecular N—H⋯N hydrogen bond between the biuret NH atom and the quinoline ring nitro­gen defines the crystal packing

(4-Chlorophenyl)(2-hydroxy-7-methoxynaphthalen-1-yl)methanone

The title compound, C18H13ClO3, has an intra­molecular O—H⋯O=C hydrogen bond between the carbonyl group and the hydr­oxy substituent on the naphthalene ring system. The angle between the C=O bond plane and the naphthalene ring system is relatively small [20.96 (8)°]. The angle between the benzene ring and the carbonyl group is rather large [35.65 (9)°] compared to that in an analogous compound [3.43 (11)°] having a meth­oxy group instead of a hydroxy substituent

A DISTANCE LEARNING SYSTEM WITH CUSTOMIZABLE SCREEN LAYOUTS FOR MULTIPLE LEARNING SITUATIONS

In this paper, we propose a new distance learning system that can adapt to various styles of learning activity. We assume that the system is used in distance classes with multiple live-streaming videos. Our system has functions to change the screen layout to best suit for the current learning situation for each of the participants in a class. The system also has a function to efficiently monitor the behavior of many students at a time. These functions enable us to adapt various learning activities in distance learning classes. We implemented a prototype of the proposed system and evaluated it in experimental classes. We confirmed that our system improved the activities in the experimental classes

(8-Bromo-2-hydroxy-7-methoxy-1-naph­thyl)(4-chlorobenzoyl)methanone

In the title compound, C18H12BrClO3, the naphthalene ring system and the benzene ring make a dihedral angle of 82.18 (9)°. The conformation around the central C=O group is such that the C=O bond vector forms a larger angle to the plane of the naphthalene ring system than to the plane of the benzene ring, viz. 60.91 (16)° versus 13.94 (16)°. In the crystal structure, two π–π inter­actions formed between the naphthalene ring systems [centroid–centroid distances of 3.8014 (13) and 3.9823 (13) Å] and inter­molecular O—H⋯O and C—H⋯O hydrogen bonds are present

1,8-Dibenzoyl-2,7-dimethoxy­naphthalene

The mol­ecule of the title compound, C26H20O4, is located on a twofold rotation axis. The two benzoyl groups are situated in an anti orientation. The dihedral angle between the mean planes of the phenyl ring and the naphthalene ring system is 80.25 (6)°. The phenyl and carbonyl groups in each benzoyl group are almost coplanar. The mol­ecular packing is stabilized by weak C—H⋯O hydrogen bonds and a π–π stacking inter­action between the phenyl rings [centroid–centroid and inter­planar distances of 3.6383 (10) and 3.294 Å, respectively]

Choline dihydrogen phosphate

In the cystal structure of the title compound, (2-hy­droxy­ethyl)trimethylammonium dihydrogen phosphate, C5H14NO+·H2PO4 −, two anions create dimeric structures via two O—H⋯O hydrogen bonds. The hydrogen-bonded dimers are connected by another O—H⋯O hydrogen bond with the hydroxyl groups of the cations, constructing a columner structure along the a axis. A number of C—H⋯O interactions are also present