Coordination of DNA Base Excision Repair by Protein-Protein Interactions

The system of base excision repair (BER) evolved to correct the most abundant DNA damages in mammalian cells is the most essential for maintaining the genome integrity. The multistep BER process involves several enzymes and protein factors functioning in a coordinated fashion that ensures the repair efficiency. The coordination is facilitated by the formation of protein complexes stabilized via either direct or indirect DNA-mediated interactions. This review focuses on direct interactions of proteins participating in BER with each other and with noncanonical factors found recently to modulate the efficiency of BER. All the known partners of main BER participants, the sites responsible for their interaction, and the characteristics of protein-protein affinity are summarized. Well-documented evidences of how DNA intermediates and posttranslational modifications of proteins modulate protein-protein interactions are presented. The available data allow to suggest that the multiprotein complexes are assembled with the involvement of a scaffold protein XRCC1 and poly(ADP-ribose) polymerase 1, a key regulator of the BER process, irrespective of the DNA damage; the composition and the structure of the complexes are dynamically changed depending on the DNA damage, its chromatin environment, and the step of BER process

AP-site cleavage activity of tyrosyl-DNA phosphodiesterase 1

AbstractAPE-independent base excision repair (BER) pathway plays an important role in the regulation of DNA repair mechanisms. In this study it has been found that recently discovered tyrosyl-DNA phosphodiesterase 1 (Tdp1) catalyzes the AP site cleavage reaction to generate breaks with the 3′- and 5′-phosphate termini. The removal of the 3′-phosphate is performed by polynucleotide kinase phosphatase (PNKP). Tdp1 is known to interact stably with BER proteins: DNA polymerase beta (Pol β), XRCC1, PARP1 and DNA ligase III. The data suggest a role of Tdp1 in the new APE-independent BER pathway in mammals

Influence of fluorides on phase relations in the molten systems MI2O-Р2О5 Mn2O3/MIIO, МI – Li, Na, K; MII – Ni, Co

Addition of alkaline fluorides to molten phosphates with a composition MI2O-Р2О5-Mn2O3 and MI2O-Р2О5-MIIO (МI – Li, Na, K) gradually changes the solubility of polyvalent metals oxides and shifts the crystallization areas in the corresponding melts. The results obtained are based on solubility curves found for Mn2O3, СоО and NiO in the fluxes of MI2O-Р2О5 -MF and MI2O-Р2О5 -MF (where МI – Li, Na, K) and X-Ray diffraction, IR spectroscopy and thermal analysis. The presence of 10 and 20 % mass of fluorides provides molten polyphosphates depolymerization and yields pyro- Li2MnP2O7, K2CoP2O7, Na2CoP2O7and orthophosphates Na2Mn3(P2O7)2, NaMnPO4, NaNiPO4 single crystals growth

Портрет учёного в публикациях: памяти Бориса Степановича Елепова

Based on the analysis of the publications by Boris S. Elepov, former Director of SPSL SB RAS, Dr. Sc. (Engineering), main directions of his scientific and practical activity are outlined. As a result of his activities, SPLS&T SB RAS established as a research institute, Center of scientific and technical information SB RAS, modern public library, the book Museum, a scientific and methodological centre for information and library systems of SB RAS, Siberian regional library center of continuing education, the Siberian regional center of documents conservation, regional multi-functional center providing patent information services in the field of protection of intellectual property.На основе анализа публикаций директора ГПНТБ СО РАН - профессора Б. С. Елепова (1942-2016) выделены главные направления его научной и практической деятельности и представлены её итоги: становление ГПНТБ СО РАН как НИИ, Центра НТИ СО РАН, современной публичной библиотеки, Музея книги, научно-методического центра для информационно-библиотечной системы СО РАН, Сибирского регионального центра непрерывного библиотечного образования, Сибирского регионального центра консервации документов, многофункционального центра региона по предоставлению патентно-информационных услуг в области охраны и защиты объектов интеллектуальной собственности

Tyrosyl-DNA phosphodiesterase 1 initiates repair of apurinic/apyrimidinic sites

AbstractTyrosyl-DNA phosphodiesterase 1 (Tdp1) catalyzes the hydrolysis of the phosphodiester linkage between the DNA 3′ phosphate and a tyrosine residue as well as a variety of other DNA 3′ damaged termini. Recently we have shown that Tdp1 can liberate the 3′ DNA phosphate termini from apurinic/apyrimidinic (AP) sites. Here, we found that Tdp1 is more active in the cleavage of the AP sites inside bubble-DNA structure in comparison to ssDNA containing AP site. Furthermore, Tdp1 hydrolyzes AP sites opposite to bulky fluorescein adduct faster than AP sites located in dsDNA. Whilst the Tdp1 H493R (SCAN1) and H263A mutants retain the ability to bind an AP site-containing DNA, both mutants do not reveal endonuclease activity, further suggesting the specificity of the AP cleavage activity. We suggest that this Tdp1 activity can contribute to the repair of AP sites particularly in DNA structures containing ssDNA region or AP sites in the context of clustered DNA lesions

Human base excision repair enzymes apurinic/apyrimidinic endonuclease1 (APE1), DNA polymerase β and poly(ADP-ribose) polymerase 1: interplay between strand-displacement DNA synthesis and proofreading exonuclease activity

We examined interactions between base excision repair (BER) DNA intermediates and purified human BER enzymes, DNA polymerase β (pol β), apurinic/apyrimidinic endonuclease (APE1) and poly(ADP-ribose) polymerase-1 (PARP-1). Studies under steady-state conditions with purified BER enzymes and BER substrates have already demonstrated interplay between these BER enzymes that is sensitive to the respective concentrations of each enzyme. Therefore, in this study, using conditions of enzyme excess over substrate DNA, we further examine the question of interplay between BER enzymes on BER intermediates. The results reveal several important differences compared with data obtained using steady-state assays. Excess PARP-1 antagonizes the action of pol β, producing a complete block of long patch BER strand-displacement DNA synthesis. Surprisingly, an excess of APE1 stimulates strand-displacement DNA synthesis by pol β, but this effect is blocked by PARP-1. The APE1 exonuclease function appears to be modulated by the other BER proteins. Excess APE1 over pol β may allow APE1 to perform both exonuclease function and stimulation of strand-displacement DNA synthesis by pol β. This enables pol β to mediate long patch sub-pathway. These results indicate that differences in the stoichiometry of BER enzymes may regulate BER

Журналы по проблемам библиотековедения и библиографоведения: многоаспектный наукометрический анализ

The findings of the scientometric analysis of national journals in library science and bibliography are presented. Based on Science Index data, the rating of the journals under the subject headings “Culture” and “Information Studies” of the Russian Science Citation Index by citations number, number of citations excluding self-citation, two-year impact-factor, and two-year impact factor excluding self-citation is drawn up. The authors argue that these results can be extrapolated on the national library science. The article is based on the paper presented at the Second World Professional Forum “The Book. Culture. Education. Innovations” - “Crimea-2016”.Представлен наукометрический анализ отечественных журналов по проблемам библиотековедения и библиотечного дела. На основании данных Science Index рассмотрен уровень журналов по рубрикам «Культура» и «Информатика» РИНЦ, в которых публикуются статьи по библиотечному делу и библиотековедению. Составлен рейтинг журналов в рамках рубрики «Культура. Культурология» РИНЦ по показателям Science Index , числу цитирований, числу цитирований без самоцитирования, двухлетнему импакт-фактору и двухлетнему импакт-фактору без самоцитирования. Результаты проведённого анализа можно проецировать на состояние библиотечной науки в стране. Статья подготовлена на основе доклада на Втором международном профессиональном форуме «Книга. Культура. Образование. Инновации» - «Крым-2016»

Межрегиональная научно-практическая конференция «Библиотека традиционная и электронная: смыслы и ценности»: итоги работы

The results of the interregional research and practical conference “Traditional and Electronic Libraries: The essence and values” (October 4-6, 2016, Novosibirsk) are discussed, its participants are introduced. The Conference agenda is characterized. Several events are discussed, including the round table in memory of Boris Elepov.Подведены итоги межрегиональной научно-практической конференции «Библиотека традиционная и электронная: смыслы и ценности» (4-6 окт. 2016 г., Новосибирск), представлены её участники. Охарактеризована программа конференции, перечислены её темы. Освещены отдельные мероприятия, в том числе «круглый стол», посвящённый памяти Б. С. Елепова