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Glushakova A. M. Lysak L. V. Kachalkin A. V. Ivanova A. E. Umarova A. B. Abramyan I. A. Ezhelev Z. S. Maksimova I. A. 《Microbiology》2021,90(2):176-186
Microbiology - In a model experiment, the transformation of microbial complexes of cultivated saprotrophic bacteria and yeasts during freezing-thawing was studied in various natural substrates that... 相似文献
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Juan M. González D. Sheckells Mareike Viebahn Donara Krupatkina Kimberly M. Borges F. T. Robb 《Archives of microbiology》1999,172(2):95-101
An extremely thermophilic, sulfur-dependent archaeon, strain WT1, was isolated from a freshwater hot spring in the Lake Taupo
area of North Island, New Zealand. The cells are flagellated, strictly anaerobic cocci that grow optimally at 85 °C and 5.4
g NaCl l–1. The strain grows heterotrophically on complex proteinaceous substrates or on appropriate salts plus amino acid mixtures
and is also able to utilize maltose, starch, and pyruvate. Elemental sulfur could be replaced by cystine or thioglycollate.
The range of temperatures allowing growth is from 60 to 90 °C; the pH supporting growth ranges from 5 to 8 (optimum, pH 7).
Strain WT1 grew in a defined medium containing amino acids as the sole carbon and energy sources. The required amino acids
were: Arg, His, Ile, Leu, Phe, Ser, Thr, Trp, Tyr, and Val. Strain WT1 showed sensitivity to rifampicin. DNA G+C content was
50.4 mol%. Phylogenetic analysis of the sequence encoding the 16S rRNA gene indicated that this isolate is a member of the
Thermococcales. DNA/DNA hybridization studies revealed no similarity to several species of Thermococcus and Pyrococcus, with the exception of Thermococcus zilligii. Based on the reported results, we propose strain WT1 as a new species to be named Thermococcus waiotapuensis sp. nov.
Received: 5 January 1999 / Accepted: 19 May 1999 相似文献
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Fei Lou Tigran M. Abramyan Haiyan Jia Alexander Tropsha 《Journal of biomolecular structure & dynamics》2020,38(17):5204-5218
AbstractPlants uniquely have a family of proteins called extra-large G proteins (XLG) that share homology in their C-terminal half with the canonical Gα subunits; we carefully detail here that Arabidopsis XLG2 lacks critical residues requisite for nucleotide binding and hydrolysis which is consistent with our quantitative analyses. Based on microscale thermophoresis, Arabidopsis XLG2 binds GTPγS with an affinity 100 times lower than that to canonical Gα subunits. This means that given the concentration range of guanine nucleotide in plant cells, XLG2 is not likely bound by GTP in vivo. Homology modeling and molecular dynamics simulations provide a plausible mechanism for the poor nucleotide binding affinity of XLG2. Simulations indicate substantially stronger salt bridge networks formed by several key amino-acid residues of AtGPA1 which are either misplaced or missing in XLG2. These residues in AtGPA1 not only maintain the overall shape and integrity of the apoprotein cavity but also increase the frequency of favorable nucleotide-protein interactions in the nucleotide-bound state. Despite this loss of nucleotide dependency, XLG2 binds the RGS domain of AtRGS1 with an affinity similar to the Arabidopsis AtGPA1 in its apo-state and about 2 times lower than AtGPA1 in its transition state. In addition, XLG2 binds the Gβγ dimer with an affinity similar to that of AtGPA1. XLG2 likely acts as a dominant negative Gα protein to block G protein signaling. We propose that XLG2, independent of guanine nucleotide binding, regulates the active state of the canonical G protein pathway directly by sequestering Gβγ and indirectly by promoting heterodimer formation.Communicated by Ramaswamy H. Sarma 相似文献
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David W. LaFleur Donara Abramyan Palanisamy Kanakaraj Rodger G. Smith Rutul R. Shah Geping Wang Xiao-Tao Yao Spandana Kankanala Ernie Boyd Liubov Zaritskaya Viktoriya Nam Bridget A. Puffer Pete Buasen Shashi Kaithamana Andrew F. Burnette Rajesh Krishnamurthy Dimki Patel Viktor V. Roschke Peter A. Kiener David M. Hilbert Carlos F. Barbas III 《MABS-AUSTIN》2013,5(2):208-218
The recognition that few human diseases are thoroughly addressed by mono-specific, monoclonal antibodies (mAbs) continues to drive the development of antibody therapeutics with additional specificities and enhanced activity. Historically, efforts to engineer additional antigen recognition into molecules have relied predominantly on the reformatting of immunoglobulin domains. In this report we describe a series of fully functional mAbs to which additional specificities have been imparted through the recombinant fusion of relatively short polypeptides sequences. The sequences are selected for binding to a particular target from combinatorial libraries that express linear, disulfide-constrained, or domain-based structures. The potential for fusion of peptides to the N- and C- termini of both the heavy and light chains affords the bivalent expression of up to four different peptides. The resulting molecules, called zybodies, can gain up to four additional specificities, while retaining the original functionality and specificity of the scaffold antibody. We explore the use of two clinically significant oncology antibodies, trastuzumab and cetuximab, as zybody scaffolds and demonstrate functional enhancements in each case. The affect of fusion position on both peptide and scaffold function is explored, and penta-specific zybodies are demonstrated to simultaneously engage five targets (ErbB2, EGFR, IGF-1R, Ang2 and integrin αvβ3). Bispecific, trastuzumab-based zybodies targeting ErbB2 and Ang2 are shown to exhibit superior efficacy to trastuzumab in an angiogenesis-dependent xenograft tumor model. A cetuximab-based bispecific zybody that targeting EGFR and ErbB3 simultaneously disrupted multiple intracellular signaling pathways; inhibited tumor cell proliferation; and showed efficacy superior to that of cetuximab in a xenograft tumor model. 相似文献
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