ABSTRACT
It is discussed the structural model of the management-protein complex centre participating in the O2-evolution process. The points of the model are the followings: the protein complex appears to contain only one manganese ion Mn2+. It is supposed that the manganese is complexed with the peptide chains fragment as the ligand. According to the crystallite field theory the active centre is the complex of octahedral symmetry. It is proposed that complex is formed by the skeleton of the peptide chain by the donor-accepting bonds of Mn2+ and four peptide nitrogens (d2sp3-hybridization), and two vacant orbitals are for the complex functioning.
Subject(s)
Manganese/chemistry , Models, Molecular , Proteins/chemistry , Binding Sites , Models, Theoretical , Protein BindingABSTRACT
A site-specific endonuclease which recognizes the sequence 5'-CCTNAGG-3' was purified to homogeneity from the thermophilic strain Bacillus sp. R7. The endonuclease (BspR7I) is monomeric protein with an apparent molecular weight of 37 kD. The enzyme is active over a wide range of NaCl concentrations, pH, and temperatures. BspR7I cleaves DNA substrates according to the scheme: 5'-CC decreases TNAGG-3' 3'-GGANT increases CC-5', hence the endonuclease represents an isoschizomer of Bsu361.
Subject(s)
Bacillus/enzymology , Deoxyribonucleases, Type II Site-Specific/isolation & purification , Chromatography, Gel , Enzyme Stability , Molecular Weight , Substrate SpecificityABSTRACT
NMR-spin echo and dielectric studies of water in biopolymers have been carried out. According to the data on the relationship between the time of spin-spin relaxation, the energy of movement activation and electroconductivity, and moisture-bearing it can be concluded that water sorption on biopolymers of the type of gelatin, starch, cellulose up to a certain humidity value takes place in a vacuum. With an increase of moisture-bearing the process of sorption may be presented as a solution of low-molecular substance in a high-molecular one.
