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281.
Efthymia Nikita 《American journal of physical anthropology》2021,174(1):140-143
Documented skeletal collections constitute a key resource in forensic anthropological and bioarchaeological research as they allow both the development of methods for the estimation of various parameters of an individual's biological profile, and the examination of the accuracy of existing methods in different skeletal assemblages. The acknowledgement of the utility of documented collections is attested by the large number of such collections across the world. The current review will focus on two modern reference collections in Greece, briefly presenting their composition, the research projects in which they have been employed, and future prospects for their use. 相似文献
282.
Karyagina Anna S. Gromov Alexander V. Grunina Tatyana M. Lyaschuk Alexander M. Grishin Alexander V. Strukova Natalia V. Generalova Maria S. Galushkina Zoya M. Soboleva Lyubov’ A. Dobrinina Olga Yu. Bolshakova Tatyana N. Subbotina Marina E. Romanovskaya-Romanko Ekaterina A. Krasilnikov Igor V. Polyakov Nikita B. Solovyev Andrey I. Grumov Daniil A. Zhukhovitsky Vladimir G. Ryabova Ekaterina I. Prokofiev Vladimir V. Lunin Vladimir G. 《Biochemistry. Biokhimii?a》2021,86(10):1275-1287
Biochemistry (Moscow) - A new platform for creating anti-coronavirus epitope vaccines has been developed. Two loop-like epitopes with lengths of 22 and 42 amino acid residues were selected from the... 相似文献
283.
Alexandra A. Kuznetsova Nikita A. Kuznetsov Alexander A. Ishchenko Murat K. Saparbaev Olga S. Fedorova 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Extensive structural studies of human DNA glycosylase hOGG1 have revealed essential conformational changes of the enzyme. However, at present there is little information about the time scale of the rearrangements of the protein structure as well as the dynamic behavior of individual amino acids.Methods
Using pre-steady-state kinetic analysis with Trp and 2-aminopurine fluorescence detection the conformational dynamics of hOGG1 wild-type (WT) and mutants Y203W, Y203A, H270W, F45W, F319W and K249Q as well as DNA–substrates was examined.Results
The roles of catalytically important amino acids F45, Y203, K249, H270, and F319 in the hOGG1 enzymatic pathway and their involvement in the step-by-step mechanism of oxidative DNA lesion recognition and catalysis were elucidated.Conclusions
The results show that Tyr-203 participates in the initial steps of the lesion site recognition. The interaction of the His-270 residue with the oxoG base plays a key role in the insertion of the damaged base into the active site. Lys-249 participates not only in the catalytic stages but also in the processes of local duplex distortion and flipping out of the oxoG residue. Non-damaged DNA does not form a stable complex with hOGG1, although a complex with a flipped out guanine base can be formed transiently.General significance
The kinetic data obtained in this study significantly improves our understanding of the molecular mechanism of lesion recognition by hOGG1. 相似文献284.
Nikita E. Chavarria Sungmin Hwang Shiyun Cao Xian Fu Mary Holman Dina Elbanna Suzanne Rodriguez Deanna Arrington Markus Englert Sivakumar Uthandi Dieter S?ll Julie A. Maupin-Furlow 《PloS one》2014,9(6)
While cytoplasmic tRNA 2-thiolation protein 1 (Tuc1/Ncs6) and ubiquitin-related modifier-1 (Urm1) are important in the 2-thiolation of 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) at wobble uridines of tRNAs in eukaryotes, the biocatalytic roles and properties of Ncs6/Tuc1 and its homologs are poorly understood. Here we present the first report of an Ncs6 homolog of archaea (NcsA of Haloferax volcanii) that is essential for maintaining cellular pools of thiolated tRNALysUUU and for growth at high temperature. When purified from Hfx. volcanii, NcsA was found to be modified at Lys204 by isopeptide linkage to polymeric chains of the ubiquitin-fold protein SAMP2. The ubiquitin-activating E1 enzyme homolog of archaea (UbaA) was required for this covalent modification. Non-covalent protein partners that specifically associated with NcsA were also identified including UbaA, SAMP2, proteasome activating nucleotidase (PAN)-A/1, translation elongation factor aEF-1α and a β-CASP ribonuclease homolog of the archaeal cleavage and polyadenylation specificity factor 1 family (aCPSF1). Together, our study reveals that NcsA is essential for growth at high temperature, required for formation of thiolated tRNALysUUU and intimately linked to homologs of ubiquitin-proteasome, translation and RNA processing systems. 相似文献
285.
Benjamin Vitre Nikita Gudimchuk Ranier Borda Yumi Kim John E. Heuser Don W. Cleveland Ekaterina L. Grishchuk 《Molecular biology of the cell》2014,25(15):2272-2281
Centromere protein E (CENP-E) is a highly elongated kinesin that transports pole-proximal
chromosomes during congression in prometaphase. During metaphase, it facilitates
kinetochore–microtubule end-on attachment required to achieve and maintain chromosome
alignment. In vitro CENP-E can walk processively along microtubule tracks and follow both growing
and shrinking microtubule plus ends. Neither the CENP-E–dependent transport along
microtubules nor its tip-tracking activity requires the unusually long coiled-coil stalk of CENP-E.
The biological role for the CENP-E stalk has now been identified through creation of
“Bonsai” CENP-E with significantly shortened stalk but wild-type motor and tail
domains. We demonstrate that Bonsai CENP-E fails to bind microtubules in vitro unless a cargo is
contemporaneously bound via its C-terminal tail. In contrast, both full-length and truncated CENP-E
that has no stalk and tail exhibit robust motility with and without cargo binding, highlighting the
importance of CENP-E stalk for its activity. Correspondingly, kinetochore attachment to microtubule
ends is shown to be disrupted in cells whose CENP-E has a shortened stalk, thereby producing
chromosome misalignment in metaphase and lagging chromosomes during anaphase. Together these
findings establish an unexpected role of CENP-E elongated stalk in ensuring stability of
kinetochore–microtubule attachments during chromosome congression and segregation. 相似文献
286.
Sabrina Dusi Lorella Valletta Tobias B. Haack Yugo Tsuchiya Paola Venco Sebastiano Pasqualato Paola Goffrini Marco Tigano Nikita Demchenko Thomas Wieland Thomas Schwarzmayr Tim M. Strom Federica Invernizzi Barbara Garavaglia Allison Gregory Lynn Sanford Jeffrey Hamada Conceição Bettencourt Henry Houlden Luisa Chiapparini Giovanna Zorzi Manju A. Kurian Nardo Nardocci Holger Prokisch Susan Hayflick Ivan Gout Valeria Tiranti 《American journal of human genetics》2014
287.
Teetam Ghosal Nikita Augustine Ashwini Siddapur Vaishnavi Babu Merlyn Keziah Samuel Subathra Devi Chandrasekaran 《生物学前沿》2017,12(5):376-384
Background
Screening of isolates for their potency to produce streptokinase was an important criterion of this research. The current study emphasizes the strain improvement, optimization and purification studies for enhanced production of streptokinase from Streptococcus uberis TNA-M1 isolated from bovine milk.Methods
The study was carried out on samples collected from milk sample. Primary screening and characterization is used as an excellent source for the isolation of β-hemolytic organisms. Strain improvement was done by both physical & chemical mutagenesis. The enzyme activity was checked by clot lysis assay and confirmed by fibrin plate method. The partially purified and crude enzyme were analysed by high-performance liquid chromatography. Molecular weight & enzyme purity was checked by SDS–PAGE, further confirmed by fibrin zymography.Results
Out of the 3 isolated strains, only one isolate expressed β-haemolysis with streptokinase (SK) activity. Based on the results of radial caseinolytic assay and blood clot dissolving assay, isolate TNA-M1 demonstrated the highest streptokinase activity. Based on morphological, biochemical and molecular characterization, it was identified as Streptococcus uberis and the strain was named as Streptococcus uberis TNA-M1. The results indicated that ultra-violet (UV) and ethyl methane sulfonate (EMS) were effective mutagenic agents for strain improvement of Streptococcus uberis TNA-M1 and enhanced SK productivity. HPLC analysis was performed in order to confirm the presence of streptokinase with the similar retention time (0.875 min) with its standard (0.854) min. SDS-PAGE of the enzyme showed protein band of approximately 47 kDa and confirmed by fibrin zymography. It exhibited fibrinolytic activity, which was more potent than other fibrinolytic enzymes. Glucose and peptone were recorded to be the optimum carbon and nitrogen sources respectively.Conclusion
Thus this study presents its novelty by highlighting the potential of Streptococcus uberis TNA-M1 as a significant source for the production of fibrinolytic enzymes.288.
Koval VV Kuznetsov NA Zharkov DO Ishchenko AA Douglas KT Nevinsky GA Fedorova OS 《Nucleic acids research》2004,32(3):926-935
Formamidopyrimidine-DNA-glycosylase (Fpg pro tein, MutM) catalyses excision of 8-oxoguanine (8-oxoG) and other oxidatively damaged purines from DNA in a glycosylase/apurinic/apyrimidinic-lyase reaction. We report pre-steady-state kinetic analysis of Fpg action on oligonucleotide duplexes containing 8-oxo-2′-deoxyguanosine, natural abasic site or tetrahydrofuran (an uncleavable abasic site analogue). Monitoring Fpg intrinsic tryptophan fluorescence in stopped-flow experiments reveals multiple conformational transitions in the protein molecule during the catalytic cycle. At least four and five conformational transitions occur in Fpg during the interaction with abasic and 8-oxoG-containing substrates, respectively, within 2 ms to 10 s time range. These transitions reflect the stages of enzyme binding to DNA and lesion recognition with the mutual adjustment of DNA and enzyme structures to achieve catalytically competent conformation. Unlike these well-defined binding steps, catalytic stages are not associated with discernible fluorescence events. Only a single conformational change is detected for the cleavable substrates at times exceeding 10 s. The data obtained provide evidence that several fast sequential conformational changes occur in Fpg after binding to its substrate, converting the protein into a catalytically active conformation. 相似文献
289.
Nikita Nankoo Ikechukwu Anthony Achilonu Marie Emma Christine Rey 《Current issues in molecular biology》2022,44(6):2717
South African cassava mosaic virus (SACMV) is a circular ssDNA bipartite begomovirus, whose genome comprises DNA-A (encodes six genes) and DNA-B (encodes BC1 cell-to-cell movement and BV1 nuclear shuttle proteins) components. A few secondary and tertiary structural and physicochemical characteristics of partial but not full-length begomovirus proteins have been elucidated to date. The full-length codon-optimised SACMV BC1 gene was cloned into a pET-28a (+) expression vector and transformed into expression host cells E. coli BL21 (DE3). The optimal expression of the full-length BC1-encoded movement protein (MP) was obtained via induction with 0.25 mM IPTG at an OD600 of ~0.45 at 37 °C for four hours. Denatured protein fractions (dialysed in 4 M urea), passed through an IMAC column, successfully bound to the nickel resin, and eluted using 250 mM imidazole. The protein was refolded using stepwise dialysis. The molecular weight of MP was confirmed to be 35 kDa using SDS–PAGE. The secondary structure of SACMV MP presented as predominantly β-strands. An ANS (1-anilino-8-naphthalene sulphonate)-binding assay confirmed that MP possesses hydrophobic pockets with the ability to bind ligands such as ANS (8-anilino-1-naphthalenesulphonic acid). A 2′ (3′)-N-methylanthraniloyl-ATP (mant-ATP) assay showed binding of mant-ATP to MP and indicated that, while hydrophobic pockets are present, MP also exhibits hydrophilic regions. Intrinsic tryptophan fluorescence indicated a significant conformational change in the denatured form of BC1 in the presence of ATP. In addition, a phosphatase assay showed that MP possessed ATPase activity. 相似文献
290.
Structural requirements for differential sensitivity of KCNQ K+ channels to modulation by Ca2+/calmodulin 总被引:2,自引:0,他引:2
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Calmodulin modulation of ion channels has emerged as a prominent theme in biology. The sensitivity of KCNQ1-5 K+ channels to modulation by Ca2+/calmodulin (CaM) was studied using patch-clamp, Ca2+ imaging, and biochemical and pharmacological approaches. Coexpression of CaM in Chinese hamster ovary (CHO) cells strongly reduced currents of KCNQ2, KCNQ4, and KCNQ5, but not KCNQ1 or KCNQ3. In simultaneous current recording/Ca2+ imaging experiments, CaM conferred Ca2+ sensitivity to KCNQ4 and KCNQ5, but not to KCNQ1, KCNQ3, or KCNQ1/KCNE1 channels. A chimera constructed from the carboxy terminus of KCNQ4 and the rest KCNQ1 displayed Ca2+ sensitivity similar to KCNQ4. Chimeras constructed from different lengths of the KCNQ4 carboxy terminal and the rest KCNQ3 localized a region that confers sensitivity to Ca2+/CaM. Lobe-specific mutations of CaM revealed that its amino-terminal lobe mediates the Ca2+ sensitivity of the KCNQ/CaM complex. The site of CaM action within the channel carboxy terminus overlaps with that of the KCNQ opener N-ethylmaleimide (NEM). We found that CaM overexpression reduced NEM augmentation of KCNQ2, KCNQ4, and KCNQ5, and NEM pretreatment reduced Ca2+/CaM-mediated suppression of M current in sympathetic neurons by bradykinin. We propose that two functionally distinct types of carboxy termini underlie the observed differences among this channel family. 相似文献