Structural Studies of Component of Lysoamidase Bacteriolytic Complex from <Emphasis Type="Italic">Lysobacter</Emphasis> sp. XL1

The lysoamidase bacteriolytic complex (LBC) comprising five enzymes (L1–L5) is secreted into the culture liquid by gram-negative bacterium Lysobacter sp. XL1. The medicinal agent lysoamidase has a broad-antimicrobial spectrum. Bacteriolytic protease L1 belongs to the LBC. Recombinant L1 protease of Lysobacter sp. XL1 was expressed, purified to homogeneity and crystallized. The X-ray structure of L1 at 1.35 Å resolution has been determined using the synchrotron data and the molecular replacement method. L1 protease is a thermostable whose thermal unfolding proceeds in one step without forming stable intermediates. Structural information concerning L1 will contribute to the development of new-generation antimicrobial drugs, whose application will not be accompanied by the selection of resistant microorganisms.     

Localization of beta-glucuronidase in the kidney of the white rat after administration of the antidiuretic hormone

Distribution of beta-glucuronidase, one of three enzymes of hyaluronate hydrolases (HH) that hydrolyze extracellular glycosamine glycans (GAG), has been studied in the intact white rat kidney and under effect of antidiuretic hormone (ADH). Renal beta-glucuronidase is revealed as discrete granules in cytoplasm of epithelial cells, in the cortex and medulla and in the interstitial cells of the papilla. ADH increase for a short time in blood results in decreasing amount of granules in cytoplasm of epithelial cells of the collecting tubules, and a prolonged increase is accompanied with practically a complete disappearance of granules both in cytoplasm of epitheliocytes of the collecting tubules and in spindle-like interstitial cells. This effect is considered as a result of the enzyme discharge under ADH effect from the cells into the interstitial space--the place of the extracellular GAG position, HH action substrate. The possibility of the enzyme presence in the renal cells in the form of two fractions is discussed.     

The effect of the background color of computer programs on the functional state of preschool children working on a computer

The effect of work on a computer on the functional state of preschool children (five to six years of age) using developing software (DS) with differently colored backgrounds (lettuce green, blue, black, or graypurple) has been studied. All other characteristics of DS were alike: the same children were examined while working with each of the four experimental DS. Different methods were used for processing and analysis of 240 to 1920 measurements. Only the lettuce green background proved to be adequate for five- to six-tear-old children: eight out of the nine tested indices of the functional state of preschool children showed a favorable tendency from the beginning to the end of the work. On the contrary, most indices after the work of children with DS on the blue, black, and gray-purple backgrounds (six, nine, and nine out of nine indices, respectively) were significantly impaired; impairment of the functional state of the central nervous system was detected in 14–25% of cases; general mental fatigue was observed in many cases (31–40%); and visual fatigue was found in 16–25% of cases.     

A protein with missing information about its tertiary structure folds into the compact globular structure

It has been shown by the methods of hydrodynamics (equilibrium ultracentrifugation, velocity sedimentation, intrinsic viscosity) that a fragment of the structural protein Cafl (Cafl 13.149) from the pili-like fibril Yersinia pestis is in the monomeric state and is capable of forming the compact ternary structure spontaneously, without the involvement of chaperone or other subunits. This happens despite the fact that some information about the ternary structure of this protein is provided in fibrils by the "sticky" segment Alal-Thr12 of the neighboring subunit. As previously shown, it is this segment of another molecule in the norm that is an important element of the ternary structure of the subunit itself since it interacts with the acceptor cleft and participates in the formation of the hydrophobic core.     

Interaction between CH2 and CH3-domains of human immunoglobulin G1 in glycosylated and aglycosylated Fc-fragments

Heat denaturation of glycosylated and aglycosylated human immunoglobulin G1 Fc fragments was investigated by differential scanning microcalorimetry. The enthalpy of the interaction between aglycosylated CH2 and CH3 domains is significantly reduced at 37 degrees C (but not at 0 degree C) as compared to the glycosylated form. The temperature dependence is consistent with the data on restricted proteolysis by trypsin.     

Significance of nitric oxide function in development of cardiac hypertrophy under condition of experimental renal hypertension

The development of cardiac hypertrophy was studied under condition of experimental renal hypertension on the rat. The number of cardiac nitric oxide synthase (NOS)-positive neurones increased simultaneously with the increase in NOS-activity in these neurones. A connection was found between the development of cardiac hypertrophy and the activity of NOS in cardiomiocytes. The involvement of NO in the development cardiac hypertrophy as auto- and paracrine regulator is supposed.     

The crystal structure of UUCG tetraloop

All large structured RNAs contain hairpin motifs made of a stem closed by several looped nucleotides. The most frequent loop motif is the UUCG one. This motif belongs to the tetraloop family and has the peculiarity of being highly thermodynamically stable. Here, we report the first crystal structure of two UUCG tetraloops embedded in a larger RNA-protein complex solved at 2.8 A resolution. The two loops present in the asymmetric unit are in a different crystal packing environment but, nevertheless, have an identical conformation. The observed structure is globally close to that obtained in solution by nuclear magnetic resonance. However, subtle differences point to a more detailed picture of the role played by 2'-hydroxyl groups in stabilising this tetraloop.