A study of protein structure changes during hydration by diffuse X-ray scattering: II. Fourier transform analysis of diffuse X-ray scattering data

Radial distribution functions were deduced by Fourier transform analysis of the angular dependences of diffuse X-ray scattering intensities for the following proteins with different hydration degrees: water-soluble α-protein myoglobin, water-soluble (α + β) protein lysozyme, and transmembrane proteins from the photosynthetic reaction centers of purple bacteria Rhodobacter sphaeroides and Blastochlorii (Rhodopseudomonas) viridis. The results of Fourier transform analysis of X-ray scattering intensities give quantitative characteristics of the mechanism underlying the influence of water on the formation of biological macromolecules. On the one hand, water loosens the network of hydrogen bonds, which results in a considerable conformational mobility in the molecules of lysozyme and myoglobin and the reaction centers. On the other hand, water stabilizes and orders the protein globule. A strict correlation was found between the shift of the “first” maximum of the radial distribution function, loosening of the intraglobular hydrogen bonds, increase in the intramolecular mobility, and appearance of pronounced functional activity in macromolecules. The pattern of behavior of the first maximum in the transmembrane proteins of the reaction center was similar to that observed for the water-soluble proteins. However, the first maximum reached the limiting value of 2.9 Å at a considerably lower hydration degree compared with the water-soluble proteins. A quick transition of the protein complex of the reaction center to its native state is due to the fact that the dehydrated conformation of this complex is very close to the native conformation. Comparison of the radial distribution function for water, water-soluble proteins, and transmembrane proteins suggests a quantitative conclusion that water is the least densely packed and ordered system, the water-soluble proteins are more densely packed than water, and the transmembrane proteins are the most densely packed and ordered system.     

On the role of gene of SER-4 serotonin receptor in thermotolerance of Caenorhabditis elegans behavior

Serotonin reduces the behavior tolerance of Caenorhabditis elegans of the N2 wild-type strain (swimming induced by the mechanical stimulus) to a temperature of 36°C. The sensitivity to the serotonin influence on the behavior thermotolerance remains intact in strains with null mutations of mod-1(ok103) and ser-1(ok345) serotonin receptor genes, and is almost completely lost in the ser-4(ok512) strain with null mutation in the gene of the SER-4 serotonin receptor, which is a homologue of 5-HT₁ mammalian serotonin receptor. In addition, nematodes of the ser-4(ok512) strain have high behavior thermotolerance in the absence of the exogenous serotonin compared to the N2 strain. These data indicate the involvement of the ser-4 gene in the serotonin regulation of the tolerance of C. elegance nervous system functions to hyperthermia.     

Adaptations of Malus domestica Borkh. (Rosaceae) Fruits Grown at Different Altitudes

Russian Journal of Plant Physiology - Cytophysiological adaptive features of apple fruits (Malus domestica Borkh.) were examined as a function of growth altitude—300, 500, 700, and 1200 m...     

Genetic Heterogeneity of a Diploid Grass Aegilops tauschii Revealed by Chromosome Banding Methods and Electrophoretic Analysis of the Seed Storage Proteins (Gliadins)

Russian Journal of Genetics - Genetic diversity of diploid grass Ae. tauschii Coss (2n = 2x = 14, DD), the D-genome progenitor of common wheat, was assessed using fluorescence in situ hybridization...     

Characteristics of X-ray Emission from a Micropinch Discharge at Different Polarities of the Discharge Electrodes

Plasma Physics Reports - The measurement technique and results are presented from studies of the X-ray spectra and X-ray yield from micropinch discharge plasma in a low-inductive vacuum spark...     

High-Speed Recording of Vacuum Arc Discharge Images in the Optical Range

Plasma Physics Reports - Switching of a short vacuum gap with an auxiliary discharge over the surface of a dielectric has been studied via high-speed recording of images of discharge plasma...     

A bioelectrochemical study of a suspension of Escherichia coli cells metabolizing glucose and lactose

The metabolism of glucose and lactose in Escherichia coli K-12 cells has been studied using a bioelectrochemical (BEC) approach. The magnitude and the duration of the response of a BEC anode were found to be functions of the composition of nutrient media and the concentration of bacterial cells. The amount of electricity that is generated enzymatically during the metabolism of a particular substrate depends on the activity of the relevant enzymes. This suggests that the BEC approach can be used for evaluating the activity of particular enzyme systems.     

Protein markers for identification of different species and varieties of cotton

Reference electrophoretic spectra that allow compiling electrophoretic formulas of certain cotton species and varieties were obtained on the basis of analysis of the electrophoretic spectrum of water-soluble and barely soluble proteins of seeds of diploid cotton species of genomic group A (Gossypium arboretum var. indicum, G. arboreum ssp. obtusifolum, G. herbaceum ssp. africanum, and G. herbaceum Harga), group C (G. australe, G. bickii, G. nelsone, and G. sturtianum), group D (G. davidsonii. G. harknessii. G. klotzschianum, G. raimondii, G. thurberi, and G. trilobum), and amphidiploid species of group AD (G. mustelinum, G. hirsutum ssp. palmeri, G. tricuspidatum Bagota, G. tricuspidatum Mari Galanta, G. barbadense L., and G. hirsutum L.).