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121.
122.
Matteo Ballottari Thuy B. Truong Eleonora De Re Erika Erickson Giulio R. Stella Graham R. Fleming Roberto Bassi Krishna K. Niyogi 《The Journal of biological chemistry》2016,291(14):7334-7346
Light harvesting complex stress-related 3 (LHCSR3) is the protein essential for photoprotective excess energy dissipation (non-photochemical quenching, NPQ) in the model green alga Chlamydomonas reinhardtii. Activation of NPQ requires low pH in the thylakoid lumen, which is induced in excess light conditions and sensed by lumen-exposed acidic residues. In this work we have used site-specific mutagenesis in vivo and in vitro for identification of the residues in LHCSR3 that are responsible for sensing lumen pH. Lumen-exposed protonatable residues, aspartate and glutamate, were mutated to asparagine and glutamine, respectively. By expression in a mutant lacking all LHCSR isoforms, residues Asp117, Glu221, and Glu224 were shown to be essential for LHCSR3-dependent NPQ induction in C. reinhardtii. Analysis of recombinant proteins carrying the same mutations refolded in vitro with pigments showed that the capacity of responding to low pH by decreasing the fluorescence lifetime, present in the wild-type protein, was lost. Consistent with a role in pH sensing, the mutations led to a substantial reduction in binding the NPQ inhibitor dicyclohexylcarbodiimide. 相似文献
123.
Mark J. Mitton-Fry Steven J. Brickner Judith C. Hamel Lori Brennan Jeffrey M. Casavant Michael Chen Tao Chen Xiaoyuan Ding James Driscoll Joel Hardink Thuy Hoang Erbing Hua Michael D. Huband Meghan Maloney Anthony Marfat Sandra P. McCurdy Dale McLeod Michael Plotkin Christopher Zook 《Bioorganic & medicinal chemistry letters》2013,23(10):2955-2961
A structurally novel set of inhibitors of bacterial type II topoisomerases with potent in vitro and in vivo antibacterial activity was developed. Dual-targeting ability, hERG inhibition, and pharmacokinetic properties were also assessed. 相似文献
124.
Genome analysis of a hyper acetone‐butanol‐ethanol (ABE) producing Clostridium acetobutylicum BKM19 下载免费PDF全文
Changhee Cho Donghui Choe Yu‐Sin Jang Kyung‐Jin Kim Won Jun Kim Byung‐Kwan Cho E. Terry Papoutsakis George N. Bennett Do Young Seung Sang Yup Lee 《Biotechnology journal》2017,12(2)
Previously the development of a hyper acetone‐butanol‐ethanol (ABE) producing Clostridium acetobutylicum BKM19 strain capable of producing 30.5% more total solvent by random mutagenesis of its parental strain PJC4BK, which is a buk mutant C. acetobutylicum ATCC 824 strain is reported. Here, BKM19 and PJC4BK strains are re‐sequenced by a high‐throughput sequencing technique to understand the mutations responsible for enhanced solvent production. In comparison with the C. acetobutylicum PJC4BK, 13 single nucleotide variants (SNVs), one deletion and one back mutation SNV are identified in the C. acetobutylicum BKM19 genome. Except for one SNV found in the megaplasmid, all mutations are found in the chromosome of BKM19. Among them, a mutation in the thlA gene encoding thiolase is further studied with respect to enzyme activity and butanol production. The mutant thiolase (thlAV5A) is showed a 32% higher activity than that of the wild‐type thiolase (thlAWT). In batch fermentation, butanol production is increased by 26% and 23% when the thlAV5A gene is overexpressed in the wild‐type C. acetobutylicum ATCC 824 and in its derivative, the thlA‐knockdown TKW‐A strain, respectively. Based on structural analysis, the mutation in thiolase does not have a direct effect on the regulatory determinant region (RDR). However, the mutation at the 5th residue seems to influence the stability of the RDR, and thus, increases the enzymatic activity and enhances solvent production in the BKM19 strain. 相似文献
125.
Seo-Jung Han Jae Eun Jung Do Hee Oh Minsup Kim Jae-Min Kim Kyung-Sook Chung Hee-Soo Han Jeong-Hun Lee Kyung-Tae Lee Hee Jin Jeong In Ho Park Eunkyeong Jeon Jeon-Soo Shin Dongkeun Hwang Art E. Cho Duck-Hyung Lee Taebo Sim 《Journal of enzyme inhibition and medicinal chemistry》2022,37(1):1257
Identification of highly selective type II kinase inhibitors is described. Two different chiral peptidomimetic scaffolds were introduced on the tail region of non-selective type II kinase inhibitor GNF-7 to enhance the selectivity. Kinome-wide selectivity profiling analysis showed that type II kinase inhibitor 7a potently inhibited Lck kinase with great selectivity (IC50 of 23.0 nM). It was found that 7a and its derivatives possessed high selectivity for Lck over even structurally conserved all Src family kinases. We also observed that 7a inhibited Lck activation in Jurkat T cells. Moreover, 7a was found to alleviate clinical symptoms in DSS-induced colitis mice. This study provides a novel insight into the design of selective type II kinase inhibitors by adopting chiral peptidomimetic moieties on the tail region. 相似文献
126.
Natural antibody--complement dependent neutralization of bovine herpesvirus 4 by human serum 总被引:1,自引:0,他引:1
Machiels B Gillet L Nascimento Brito SD Drion P Delforge C Nizet Y Gianello P Bona C Costes B Markine-Goriaynoff N Vanderplasschen A 《Microbes and infection / Institut Pasteur》2007,9(14-15):1530-1537
In contrast to most gammaherpesviruses, Bovine herpesvirus 4 (BoHV-4) has a broad range of host species both in vitro and in vivo. Several in vitro studies demonstrated that some human cell lines are sensitive or even permissive to BoHV-4. These observations led to the hypothesis that cross-species transmission of BoHV-4 could lead to human infections. In the present study, we investigate the sensitivity of BoHV-4 to neutralization by na?ve human sera in order to determine if humans exhibit innate anti-viral activities against this virus. Our results demonstrate that human sera from na?ve individuals, in contrast to the sera of na?ve subjects from various animal species, neutralize BoHV-4 efficiently. A series of complementary experiments were performed to unravel the mechanism(s) of this neutralization. The data obtained in this study demonstrates that human serum neutralizes BoHV-4 in a complement dependent manner activated by natural antibodies raised against the Galalpha1-3Galbeta1-4GlcNAc-R epitope expressed by bovine cells. 相似文献
127.
Reject water treatment by improvement of whole cell anammox entrapment using polyvinyl alcohol/alginate gel 总被引:1,自引:0,他引:1
Reject water treatment performance was investigated by whole cell anammox sludge entrapped polyvinyl alcohol/sodium alginate
gel in the stirred tank reactor (STR). The whole experiment was conducted through Phase 1 and Phase 2 in which synthetic wastewater
and modified reject water were used as feeding medium, respectively. The anammox reactor demonstrated quick start-up after
22 days as well as stable and relatively high nitrogen removal rate of more than 8.0 kg-N m−3 day−1 during the two both phases even under moderately low temperature of 25 ± 0.5°C during the last 2 months of Phase 2. The matured
brownish red PVA beads had good characteristics with buoyant density of 1.10 g cm−3, settling velocity of 141 m h−1 and diameter of 4 mm. The bacterial community was identified by 16S rDNA analysis revealing the concurrent existence of KSU-1
and new kind anammox bacterium Kumadai-I after changing influent from synthetic wastewater to reject water. It was speculated
that Kumadai-I might play a role as “promotion” factor together with KSU-1 on high nitrogen removal rate. These results demonstrate
the potential application of whole cell anammox entrapment by PVA/alginate gel for achieving stable and high-rate nitrogen
removal from high ammonium with low C/N ratio contained wastewaters, such as reject water, digester liquor or landfill leachate. 相似文献
128.
A C Frantz A D McDevitt L C Pope J Kochan J Davison C F Clements M Elmeros G Molina-Vacas A Ruiz-Gonzalez A Balestrieri K Van Den Berge P Breyne E Do Linh San E O ?gren F Suchentrunk L Schley R Kowalczyk B I Kostka D ?irovi? N ?prem M Colyn M Ghirardi V Racheva C Braun R Oliveira J Lanszki A Stubbe M Stubbe N Stier T Burke 《Heredity》2014,113(5):443-453
Although the phylogeography of European mammals has been extensively investigated
since the 1990s, many studies were limited in terms of sampling distribution, the
number of molecular markers used and the analytical techniques employed, frequently
leading to incomplete postglacial recolonisation scenarios. The broad-scale genetic
structure of the European badger (Meles meles) is of interest as it may
result from historic restriction to glacial refugia and/or recent anthropogenic
impact. However, previous studies were based mostly on samples from western Europe,
making it difficult to draw robust conclusions about the location of refugia,
patterns of postglacial expansion and recent demography. In the present study,
continent-wide sampling and analyses with multiple markers provided evidence for two
glacial refugia (Iberia and southeast Europe) that contributed to the genetic
variation observed in badgers in Europe today. Approximate Bayesian computation
provided support for a colonisation of Scandinavia from both Iberian and southeastern
refugia. In the whole of Europe, we observed a decline in genetic diversity with
increasing latitude, suggesting that the reduced diversity in the peripheral
populations resulted from a postglacial expansion processes. Although MSVAR v.1.3
also provided evidence for recent genetic bottlenecks in some of these peripheral
populations, the simulations performed to estimate the method''s power to
correctly infer the past demography of our empirical populations suggested that the
timing and severity of bottlenecks could not be established with certainty. We urge
caution against trying to relate demographic declines inferred using MSVAR with
particular historic or climatological events. 相似文献
129.
Hoon Kim D Jeon Choi S Kook S Kim W Keun Song W 《Biochemical and biophysical research communications》2003,300(1):141-148
We previously demonstrated caspase-mediated cleavage of p130cas during apoptosis and identified two caspase-3 cleavage sites [1]. In this study, we investigated the phosphorylation-dependent cleavage of p130cas in apoptotic Rat-1 fibroblast cells. Lysophosphatidic acid and fibronectin induced p130cas phosphorylation, which in turn resulted in resistance to caspase-mediated cleavage. Alternatively, dephosphorylation by calf intestinal alkaline phosphatase, PP1, and LAR stimulated cleavage of p130cas by caspase-3, generating a 31-kDa fragment. During apoptosis, p130cas dephosphorylation seems to precede its cleavage. The phosphorylation of tyrosine and serine residues immediately adjacent to the two cleavage sites (DVPD(416) and DSPD(748)) strongly affected p130cas cleavage by caspase-3, both in vitro and in vivo. Furthermore, the generation of the 31-kDa cleavage fragment was strongly regulated by phosphorylation of a tyrosine residue at position 751 (DSPD(748) and GQY(751)). Our results collectively suggest that degradation of p130cas during apoptosis is modulated in a phosphorylation-dependent manner. 相似文献
130.
A selective molecularly imprinted polymer for immobilization of acetylcholinesterase (AChE): an active enzyme targeted and efficient method 下载免费PDF全文
Gökhan Demirci Yasemin İspirli Doğaç Mustafa Teke 《Journal of molecular recognition : JMR》2015,28(11):645-650
In the present study, we immobilized acetylcholinesterase (AChE) enzyme onto acetylcholine removed imprinted polymer and acetylcholine containing polymer. First, the polymers were produced with acetylcholine, substrate of AChE, by dispersion polymerization. Then, the enzyme was immobilized onto the polymers by using two different methods: In the first method (method A), acetylcholine was removed from the polymer, and then AChE was immobilized onto this polymer (acetylcholine removed imprinted polymer). In the second method (method B), AChE was immobilized onto acetylcholine containing polymer by affinity. In method A, enzyme‐specific species (binding sites) occurred by removing acetylcholine from the polymer. The immobilized AChE reached 240% relative specific activity comparison with free AChE because the active enzyme molecules bounded onto the polymer. Transmission electron microscopy results were taken before and after immobilization of AChE for the assessment of morphological structure of polymer. Also, the experiments, which include optimum temperature (25–65°C), optimum pH (3–10), thermal stability (4–70°C), kinetic parameters, operational stability and reusability, were performed to determine the characteristic of the immobilized AChE. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献