New procedures are outlined that enable ARP/wARP to automatically build protein models with diffraction data extending to about 2.5 Å. An overview of ongoing research is given and possible future advances are discussed.

This paper describes the crystal structure of AF0173, a putative redox-enzyme maturation protein (REMP) from Archaeoglobus fulgidus. The REMPs serve as chaperones in the maturation of extracytoplasmic oxidoreductases in archaea and bacteria. The all-helical subunits of AF0173 form a dimer arising from the interaction of residues located in a funnel-shaped cavity on one subunit surface with an uncut expression tag from the other subunit. This cavity is likely to represent a binding site for the twin-arginine motif that interacts with REMPs. The conservation of the overall fold in AF0173 and bacterial REMPs as well as the presence of conserved residues in their putative binding sites indicates that REMPs act in a similar manner in archaea and bacteria despite their limited sequence similarity. A model of the binding of the twin-arginine motif by AF0173 is suggested. The solution of the AF0173 structure by the single anomalous dispersion method represents an extreme case of SAD structure determination: low resolution (3.4 A), the absence of NCS and the presence of only two anomalously scattering atoms in the asymmetric unit. An unusually high solvent content (73%) turned out to be important for the success of the density-modification procedures.

Metal binding by apo-manganese superoxide dismutase (apo-MnSOD) is essential for functional maturation of the enzyme. Previous studies have demonstrated that metal binding by apo-MnSOD is conformationally gated, requiring protein reorganization for the metal to bind. We have now solved the X-ray crystal structure of apo-MnSOD at 1.9 Å resolution. The organization of active site residues is independent of the presence of the metal cofactor, demonstrating that protein itself templates the unusual metal coordination geometry. Electrophoretic analysis of mixtures of apoand (Mn 2 )-MnSOD, dye-conjugated protein, or C-terminal Strep-tag II fusion protein reveals a dynamic subunit exchange process associated with cooperative metal binding by the two subunits of the dimeric protein. In contrast, (S126C) (SS) apo-MnSOD, which contains an inter-subunit covalent disulfide crosslink, exhibits anticooperative metal binding. The protein concentration dependence of metal uptake kinetics implies that protein dissociation is involved in metal binding by the wild type apo-protein, although other processes may also contribute to gating metal uptake. Protein concentration dependent small-zone size exclusion chromatography is consistent with apoMnSOD dimer dissociation at low protein concentration (K D = 1×10 −6 M). Studies on metal uptake by apo-MnSOD in Escherichia coli cells show that the protein exhibits similar behavior in vivo and in vitro.

The article analyzes the research results of a number of analytical agencies regarding the growth rate and key problems associated with the introduction of the "Internet of things" (IoT) in the agricultural economy. The issues of the development of the agro-industrial complex in the context of the development of the digital economy, the experience of introducing the digital economy in the agricultural sector of developed countries and the possibilities of its application in agriculture in Russia are considered. The authors focuses on the positive aspects of the influence of the "Internet of things" on the functioning and development of modern agricultural markets at the macro and micro levels, and the change in the professional structure of the agricultural industry

Topological and metric entropies of the DNA sequences from different organisms were calculated. Obtained results were compared each other and with ones of corresponding artificial sequences. For all envisaged DNA sequences there is a maximum of heterogeneity. It falls in the block length interval [5,7]. Maximum distinction between natural and artificial sequences is shifted on 1-3 position from the maximum of heterogeneity to the right as for metric as for topological entropy. This point on the specificity of real DNA sequences in the interval.Comment: 10 pages 7 figures submitted to PL