[Secondary structure of SsoII-like (cytosine-5)-DNA methyltransferases N-terminal region determined by circular dichroism spectroscopy].

(Cytosine-5)-DNA methyltransferase SsoII (M.SsoII) has a long N-terminal region (1-71 residues) preceding the sequence with conservative motifs, which are characteristic for all DNA methyltransferases of such kind. The presence of this region provides M.SsoII capability to act as a transcription regulator in SsoII restriction-modification system. To perform its regulatory function, M.SsoII binds specifically to a 15-mer inverted repeat in the promoter region of SsoII restriction-modification system genes. In the present work, properties of the protein delta(72-379)M.Ecl18kI are studied, which is a deletion mutant of the SsoII-like DNA-methyltransferase M.Ecl18kI and is homologous to M.SsoII N-terminal region. delta(72-379)M.Ecl18kI capability to bind specifically a DNA duplex containing the regulatory site is demonstrated. However, such a binding takes place only in the presence of high protein excess relative to DNA, which could indicate an altered structure in the deletion mutant in comparison with the full-length M.SsoII. Circular dichroism spectroscopy demonstrated that delta(72-379)M.Ecl18kI has a strongly pronounced secondary structure and contains 32% a-helices and 20% beta-sheets. Amino acid sequences alignment of M.SsoII N-terminal region and transcription factors of known spatial structure is made. An assumption is made how alpha-helices and beta-sheets are arranged in M.SsoII N-terminal region.

[Conserved structural features of ETS domain--DNA complexes].

ETS proteins comprise a family of widespread transcription factors regulating expression of many animal genes. Structurally ETS proteins are characterized by conserved DNA-binding ETS domain, recognizing DNA sequences with trinucleotide GGA. Comparative analysis of structural features of ETS domain-DNA complexes was carried out and conserved contacts, important in terms of interaction stability and specificity were identified. The analysis revealed 9 conserved hydrogen bonds with DNA backbone phosphates and 2 conserved bidentate hydrogen bonds with DNA major groove atoms, one conserved hydrophobic cluster on protein-DNA interface, important for binding site recognition, and 12 conserved water molecules, possibly mediating ETS domain-DNA interaction. The results are represented in specialized data bank of protein-DNA complexes NPIDB.

[Target-directed search of anti-virulence drugs].

Modern medicine now encounters with problem of the absence of effective antibacterial drugs, which are able to render therapeutic effect on chronic form of infectious process. Thus, the actual objective is to develop essentially new generation of drugs, on the basis of which should lie identification of new bacterial targets playing key role in process of chronization of infection as well as selection of new physiologically active substances, which are able to render highly specific inhibitory effect on selected target. Solving of this objective is possible during realization of new approaches for search and design of new drugs and, first of all, during usage of bioinformatics methods, which enable to identify new biotargets, select most effective chemical compounds-inhibitors and optimize their pharmacological and pharmacokinetic properties. The most promising bacterial target is secretion systems of pathogenic microorganisms participating in realization of their virulent characteristics and playing major role in transition of infectious process in chronic phase. We performed synthesis of and screening for 80 compounds, which allowed to select a range of inhibitors rendering specific target-directed effect on type 3 secretion system of Chlamydia. Obtained data allow to further assess of biological and therapeutic activity of these compounds on developed models of infectious process in vivo.

[Effector proteins of Clamidia].

The review summarizes the recent published data on molecular mechanisms of Chlamidiae - host cell interaction, first of all on chlamydial effector proteins. Such proteins as well as III transport system proteins that transfer many effector proteins into host cytoplasm are attractive targets for drug therapy of chlamydial infections. The majority of the data concerns two species, Chlamydia trachomatis and Chlamydophila pneumoniae. C. trachomatis protein TARP, which is presynthesized in elementary bodies, plays an essential role in the initial stages of the infection. Patogen proteins participating in the next stage, that is the intracellular inclusion traffic to the centrosome, are CT229 of C. trachomatis and Cpn0585 of C. pneumoniae, which interact with cellular Rab GTPases. In C. trachomatis, IncA protein plays a key role in chlamydial inclusions fusion, CT847 modulates life cycle of the host cell, LDA3 is essential in acquisition of nutrients. CPAF protease and inclusion membrane proteins IncG and CADD participate in suppression of apoptosis of infected cells. The proteases CPAF and CT441, as well as deubiquitinating ChlaDub1 protein, contribute to avoiding the immune response.

[Structural aspects of homeodomain interactions with DNA]. / Strukturnye aspekty vzaimodeistviia gomeodomenov s DNK.

This review is devoted to the structural aspects of interaction of homeodomains with DNA. Presented are the list of all homeodomains with known spatial structure and the alignment of their amino acid sequences. The structure of homeodomains and contacts of their amino acid residues with DNA bases and sugar-phosphate backbone are described. The role of water molecules in DNA binding is discussed. Structures of multicomponent protein complexes on DNA including homeodomains are characterized.

[Theoretical approaches for evaluation of DNA-protein interactions]. / Teoreticheskie podkhody k otsenke spetsificheskogo DNK-belkovogo vzaimodeistviia.

The notion of the DNA-recognizing segment of a protein for three-dimensional structures of DNA-protein complexes was formalized. Algorithms for calculating two parameters, hydrogen bonds and hydrophobic contacts, that characterize the interaction of the DNA-recognizing segment of the protein with the groove DNA major were proposed. DNA-recognizing protein segments in three-dimensional structures (of complexes) were classified according to these two parameters. These data were compared with the classification of the corresponding DNA-recognizing domains according to structure. The contribution of each pair amino acid residue-base to the interaction of protein with the DNA major groove was calculated.

[Possibility of predicting intrauterine fetal growth retardation by a single ultrasonic examination (using varying standards)]. / Vozmozhnost' prognozirovaniia zaderzhki vnutriutrobnogo razvitiia ploda po odnokratnomu ul'trazvukovomu issledovaniiu (s ispol'zovaniem skol'ziashchikh normativov).

The paper deals with early prediction of fetal growth retardation and its severity in a newborn from single ultrasound fetal biometric findings (biparietal head size, chest and belly diameters) at week 20 of pregnancy. The prediction was made by employing the developed varying standards for these parameters as percentile curves and tables. A stepwise prediction of fetal growth retardation was proposed for obstetric in- and outpatient settings, which was presented as an IBM personal computer dialogue program. The positive diagnostic value of fetal growth retardation prediction was found to be 69.7%, its negative value was 86.9%. The paper discusses whether therapeutic measures and pregnancy length affect the efficiency of its prediction and stresses that the prediction is valuable for individual well-grounded tactics for pregnancy management.

[Chronic placental insufficiency: incidence and causes]. / Khronicheskaia platsentarnaia nedostatochnost': chastota i prichiny vozniknoveniia.

This population study has examined the incidence and determinants of placental insufficiency. Predictors of placental dysfunction were ascertained. They included somatic diseases, gestational complications, a positive obstetric and gynecologic history and a series of constitutional factors. Populations of primiparae+- and multigravidae at risk of placental insufficiency were identified.

[Prognosis of recurrence of peptic ulcer after isolated selective proximal vagotomy]. / Prognozirovanie retsidiva iazvennoi bolezni posle izolirovannoi selektivnoi proksima'lnoi vagotomii.

The joint work of doctors and mathematicians is based upon their 20-years experience with performing vagotomy in the clinic. Prognosis of recurrence of ulcer disease was elaborated on materials of 141 operations of isolated selective proximal vagotomy for chronic duodenal ulcer. The dispensary principle of managing the patients after operation allowed obtaining objective data both in the nearest and remote (over 10 years) periods. A group of 20 patients with recurrent ulcers and 13 patients with hypersecretion gastroduodenitis was considered to have unfavorable postoperative status. The prognosis developed may be used to make the indications to isolated selective proximal vagotomy more exact. The prognosis was correct in 80% of the observations.