排序方式: 共有47条查询结果,搜索用时 15 毫秒
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Yu XD Fooks LJ Moslehi-Mohebi E Tischenko VM Askarieh G Knight SD Macintyre S Zavialov AV 《Journal of molecular biology》2012,417(4):294-308
The chaperone/usher pathway assembles surface virulence organelles of Gram-negative bacteria, consisting of fibers of linearly polymerized protein subunits. Fiber subunits are connected through 'donor strand complementation': each subunit completes the immunoglobulin (Ig)-like fold of the neighboring subunit by donating the seventh β-strand in trans. Whereas the folding of Ig domains is a fast first-order process, folding of Ig modules into the fiber conformation is a slow second-order process. Periplasmic chaperones separate this process in two parts by forming transient complexes with subunits. Interactions between chaperones and subunits are also based on the principle of donor strand complementation. In this study, we have performed mutagenesis of the binding motifs of the Caf1M chaperone and Caf1 capsular subunit from Yersinia pestis and analyzed the effect of the mutations on the structure, stability, and kinetics of Caf1M-Caf1 and Caf1-Caf1 interactions. The results suggest that a large hydrophobic effect combined with extensive main-chain hydrogen bonding enables Caf1M to rapidly bind an early folding intermediate of Caf1 and direct its partial folding. The switch from the Caf1M-Caf1 contact to the less hydrophobic, but considerably tighter and less dynamic Caf1-Caf1 contact occurs via the zip-out-zip-in donor strand exchange pathway with pocket 5 acting as the initiation site. Based on these findings, Caf1M was engineered to bind Caf1 faster, tighter, or both faster and tighter. To our knowledge, this is the first successful attempt to rationally design an assembly chaperone with improved chaperone function. 相似文献
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Blizniukov O. P. Kozmin L. D. Falikova V. V. Martynov A. I. Tischenko V. M. 《Molecular Biology》2003,37(6):912-919
The molecular mass and sedimentation coefficient of native C-reactive protein in solution were determined by analytical ultracentrifugation in the presence and absence of calcium ions. Pentameric C-reactive protein was shown to be the major macroscopic form of this protein in solution. The removal of calcium ions from solution caused decompaction of the protein accompanied by changes in its hydrodynamic parameters. The sedimentation coefficient s
0
20,w
of pentameric C-reactive protein in solution containing 2 mM Ca2+ (6.6S) exceeded that for C-reactive protein in solution containing 2 mM EDTA (6.4S). Analysis of average molecular masses M
w and M
z obtained from sedimentation data demonstrated that the solution of highly purified protein was not homogeneous. As shown by intermolecular crosslinking, the solution also contained the 241-kDa decamer of C-reactive protein (9.5S) as a separate macroscopic form, whose share hardly reached 10% in the presence of 2 mM Ca2+ and increased after removal of calcium ions. The decamers were shown to result from intermolecular association of the pentamers. 相似文献
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S.D. Trakhanov M.M. Yusupov S.C. Agalarov M.B. Garber S.N. Ryazantsev S.V. Tischenko V.A. Shirokov 《FEBS letters》1987,220(2):319-322
Well-ordered three-dimensional crystals of 70 S ribosomes and 30 S ribosomal subunits from extremely thermophilic bacteria Thermus thermophilus have been obtained. Positively stained thin sections of the crystals have been analyzed by electron microscopy. Redissolved crystalline ribosomes and small ribosomal subunits reveal sedimentation constants of 70 S and 30 S, respectively, and are functionally active in the poly(U)-system. 相似文献
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Pedro LC Pinheiro João CR Cardoso Ana S Gomes Juan Fuentes Deborah M Power Adelino VM Canário 《BMC evolutionary biology》2010,10(1):373
Background
Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evolution of these proteins. Although PTH and PTHrP have been intensively studied in mammals their function in other vertebrates is poorly documented. Amphibians and birds occupy unique phylogenetic positions, the former at the transition of aquatic to terrestrial life and the latter at the transition to homeothermy. Moreover, both organisms have characteristics indicative of a complex system in calcium regulation. This study investigated PTH family evolution in vertebrates with special emphasis on Xenopus and chicken. 相似文献6.
V. M. Tischenko 《Molecular Biology》2011,45(6):967-975
Isolated constant domains of two Bence Jones proteins, VAD and BIR, are able to form amyloid fibrils, but only the first one
retains this feature within the intact protein. The conformation and stability of these proteins were studied using scanning
microcalorimetry, circular dichroism, fluorescence spectroscopy, and analytical centrifugation at physiological conditions
(10 mM phosphate buffer, pH 7.0, 100 mM NaCl), and it was shown that isolated pairs of constant domains (CL-CL) of VAD and BIR had reduced stability in comparison to ordinary (nonamyloidogenic) Bence Jones proteins. However, in the
intact BIR protein, the stability of the constant domain block increased dramatically, in agreement with the loss of ability
to form amyloid fibrils. 相似文献
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S. I. Bakholdina N. M. Tischenko E. V. Sidorin M. P. Isaeva G. N. Likhatskaya P. S. Dmitrenok N. Yu. Kim O. V. Chernikov T. F. Solov’eva 《Biochemistry. Biokhimii?a》2016,81(1):47-57
The pldA gene encoding membrane-bound phospholipase A1 of Yersinia pseudotuberculosis was cloned and expressed in Escherichia coli cells. Recombinant phospholipase A1 (rPldA) was isolated from inclusion bodies dissolved in 8 M urea by two-stage chromatography (ion-exchange and gel-filtration chromatography) as an inactive monomer. The molecular mass of the rPldA determined by MALDI-TOF MS was 31.7 ± 0.4 kDa. The highly purified rPldA was refolded by 10-fold dilution with buffer containing 10 mM Triton X-100 and subsequent incubation at room temperature for 16 h. The refolded rPldA hydrolyzed 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine in the presence of calcium ions. The enzyme exhibited maximal activity at 37°C and nearly 40% of maximal activity at 15°C. The phospholipase A1 was active over a wide range of pH from 4 to 11, exhibiting maximal activity at pH 10. Spatial structure models of the monomer and the dimer of Y. pseudotuberculosis phospholipase A1 were constructed, and functionally important amino acid residues of the enzyme were determined. Structural differences between phospholipases A1 from Y. pseudotuberculosis and E. coli, which can affect the functional activity of the enzyme, were revealed. 相似文献
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A. O. Barabanova I. P. Tischenko V. P. Glazunov I. M. Yakovleva T. F. Solovyeva N. V. Zarubina M. G. Blokhin I. M. Yermak 《Russian Journal of Marine Biology》2010,36(3):195-200
A comparative analysis of the quantitative and qualitative composition of polysaccharides in the red seaweed Tichocarpus crinitus, collected at different sites of Peter the Great Bay in the Japanese Sea (Sivuch’ya Bay, Risovaya Bay and Sobol’ Bay) was
carried out. The sites differed in their biotopic and anthropogenic characteristics. The main monosaccharides of the investigated
algal polysaccharides were galactose and 3.6-anhydrogalactose, which are structural components of carrageenan The highest
contents of protein and glucose were found in the KCl-soluble fraction of algae from Sobol Bay that were experiencing increased
anthropogenic pressure. Fourier transform infrared spectroscopy revealed that the KCl-insoluble polysaccharide fractions of
all investigated algae had an identical structure corresponding to κ/β-carrageenan, while the KCl-soluble polysaccharide fractions
had differences in their structures. The content of heavy metals and micro- and macroelements in polysaccharide fractions
differed among algae growing in areas with different biotopic and anthropogenic conditions. 相似文献
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