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Class II aminoacyl transfer RNA synthetases: crystal structure of yeast aspartyl-tRNA synthetase complexed with tRNA(Asp) 总被引：65，自引：0，他引：65
M Ruff S Krishnaswamy M Boeglin A Poterszman A Mitschler A Podjarny B Rees J C Thierry D Moras 《Science (New York, N.Y.)》1991,252(5013):1682-1689
The crystal structure of the binary complex tRNA(Asp)-aspartyl tRNA synthetase from yeast was solved with the use of multiple isomorphous replacement to 3 angstrom resolution. The dimeric synthetase, a member of class II aminoacyl tRNA synthetases (aaRS's) exhibits the characteristic signature motifs conserved in eight aaRS's. These three sequence motifs are contained in the catalytic site domain, built around an antiparallel beta sheet, and flanked by three alpha helices that form the pocket in which adenosine triphosphate (ATP) and the CCA end of tRNA bind. The tRNA(Asp) molecule approaches the synthetase from the variable loop side. The two major contact areas are with the acceptor end and the anticodon stem and loop. In both sites the protein interacts with the tRNA from the major groove side. The correlation between aaRS class II and the initial site of aminoacylation at 3'-OH can be explained by the structure. The molecular association leads to the following features: (i) the backbone of the GCCA single-stranded portion of the acceptor end exhibits a regular helical conformation; (ii) the loop between residues 320 and 342 in motif 2 interacts with the acceptor stem in the major groove and is in contact with the discriminator base G and the first base pair UA; and (iii) the anticodon loop undergoes a large conformational change in order to bind the protein. The conformation of the tRNA molecule in the complex is dictated more by the interaction with the protein than by its own sequence. 相似文献
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Arundhati Das Jagdish Krishnaswamy Kamaljit S. Bawa M.C. Kiran N. Samba Kumar 《Biological conservation》2006,133(1):16-31
Areas of high conservation value were identified in the Western Ghats using a systematic conservation planning approach. Surrogates were chosen and assessed for effectiveness on the basis of spatial congruence using Pearson’s correlations and Mantel’s tests. The surrogates were, threatened and endemic plant and vertebrate species, unfragmented forest areas, dry forests, sub-regionally rare vegetation types, and a remotely sensed surrogate for unique evergreen ecosystems. At the scale of this analysis, amphibian richness was most highly correlated with overall threatened and endemic species richness, whereas mammals, especially wide-ranging species, were better at capturing overall animal and habitat diversity. There was a significant relationship between a remote sensing based habitat surrogate and endemic tree diversity and composition. None of the taxa or habitats served as a complete surrogate for the others. Sites were prioritised on the basis of their irreplaceability value using all five surrogates. Two alternative reserve networks are presented, one with minimal representation of surrogates, and the second with 3 occurrences of each species and 25% of each habitat type. These networks cover 8% and 29% of the region respectively. Seventy percent of the completely irreplaceable sites are outside the current protected area network. While the existing protected area network meets the minimal representation target for 88% of the species chosen in this study and all of the habitat surrogates, it is not representative with regard to amphibians, endemic tree species and small mammals. Much of the prioritised unprotected area is under reserve forests and can thus be incorporated into a wider network of conservation areas. 相似文献
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The direct immunoperoxidase test has been used to detect rinderpest virus antigens in infected bovine kidney cell cultures to study the multiplication of the virus. Infected bovine kidney coverslip cultures were sequentially tested with peroxidase-labelled, anti-rinderpest globulins at 3, 6, 24, 48, 72, 96, 120 and 144 h post-infection. The progressive virus-specific cytopathic changes compared well with the increase in the number of cells showing the presence of viral antigens when tested by the direct immunoperoxidase test. The specificity of the reaction was confirmed by using negative and antiserum-blocked BK cell cultures on coverslips. 相似文献
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Naseer A. Baba Manjit Panigrahi Ankita D. Verma Abdul Sadam Sourabh Sulabh Supriya Chhotaray Subhashree Parida Narayanan Krishnaswamy Bharat Bhushan 《Reproduction in domestic animals》2019,54(1):100-107
Progesterone (P4) plays a key role in the establishment and maintenance of pregnancy in most mammals. Unravelling the expression of progesterone‐regulated genes can expand the understanding of the embryonic mortality. Accordingly, we studied the relative mRNA expression of the P4‐regulated genes in the buffalo. Uteri were collected from the abattoir and categorized into nonpregnant late luteal phase, stage I (28–38th days of gestation) and stage II (48–56th days of gestation) of pregnancy (n = 6/group). After extraction of total RNA from the endometrial tissues, we carried out qRT‐PCR for determining the relative mRNA expression of the P4‐regulated genes using nonpregnant late luteal phase as calibrator group. The expression of LGALS3BP (essential for maternal recognition of pregnancy) gene was found to be significantly upregulated (p < 0.05), while MUC1 (important for embryo attachment) gene was downregulated in stage I and II of pregnancy. We observed no significant change in the expression of LGALS1, LGALS9 and CTSL genes. The SLC5A11 and SLC2A1 genes (involved in the transport of glucose to endometrium) in early pregnancy were upregulated in the pregnancy stage I (p < 0.05) relative to nonpregnant late luteal phase. The CST3 gene was significantly upregulated in pregnancy stage II (p < 0.01). These results provide molecular insights into the specific pathways involved in foeto‐maternal communication during early pregnancy in buffaloes. 相似文献
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B. M. Manjunatha J. P. Ravindra P. S. P. Gupta M. Devaraj T. G. Honnappa A. Krishnaswamy 《Journal of veterinary science (Suw?n-si, Korea)》2009,10(2):153-156
The present study was conducted to examine post-thaw in vitro developmental competence of buffalo embryos cryopreserved by cytoskeletal stabilization and vitrification. In vitro produced embryos were incubated with a medium containing cytochalasin-b (cyto-b) in a CO2 incubator for 40 min for microfilament stabilization and were cryopreserved by a two-step vitrification method at 24℃ in the presence of cyto-b. Initially, the embryos were exposed to 10% ethylene glycol (EG) and 10% dimethylsulfoxide (DMSO) in a base medium for 4 min. After the initial exposure, the embryos were transferred to a 7 µl drop of 25% EG and 25% DMSO in base medium and 0.3 M sucrose for 45 sec. After warming, the embryos were cultured in vitro for 72 h. The post-thaw in vitro developmental competence of the cyto-b-treated embryos did not differ significantly from those vitrified without cyto-b treatment. The hatching rates of morulae vitrified without cyto-b treatment was significantly lower than the non-vitrified control. However, the hatching rate of cyto-b-treated vitrified morulae did not differ significantly from the non-vitrified control. This study demonstrates that freezing of buffalo embryos by cytoskeletal stabilization and vitrification is a reliable method for long-term preservation. 相似文献
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Fish community responses to stream flow alterations and habitat modifications by small hydropower projects in the Western Ghats biodiversity hotspot,India 
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下载免费PDF全文 Suman Jumani Shishir Rao Nachiket Kelkar Siddarth Machado Jagdish Krishnaswamy Srinivas Vaidyanathan 《水产资源保护:海洋与淡水生态系统》2018,28(4):979-993
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Kharayat Nitish Singh Sharma G Chethan Kumar Gandham Ravi Bisht Deepika Chaudhary Gangaram Singh Sanjay Kumar Das Gautum Kumar Garg Anil Kumar Kumar Harendra Krishnaswamy Narayanan 《Veterinary research communications》2019,43(4):261-269
Veterinary Research Communications - Toll like receptors (TLRs) and β-defensins expressed in the endometrium are part of the innate uterine defense mechanism (UDM). In the present study,... 相似文献