共查询到20条相似文献，搜索用时 15 毫秒
1.
2.
Amlie Darmon Jrmie Piton Mlanie Rou Stphanie Petrella Alexandra Aubry Claudine Mayer 《Acta Crystallographica. Section F, Structural Biology Communications》2012,68(2):178-180
Mycobacterium tuberculosis DNA gyrase, a nanomachine involved in regulation of DNA topology, is the only type II topoisomerase present in this organism and hence is the sole target of fluoroquinolone in the treatment of tuberculosis. The C‐terminal domain (CTD) of the DNA gyrase A subunit possesses a unique feature, the ability to wrap DNA in a chiral manner, that plays an essential role during the catalytic cycle. A construct of 36 kDa corresponding to this domain has been overproduced, purified and crystallized. Diffraction data were collected to 1.55 Å resolution. Cleavage of the N‐terminal His tag was crucial for obtaining crystals. The crystals belonged to space group P212121, with one molecule in the asymmetric unit and a low solvent content (33%). This is the first report of the crystallization and preliminary X‐ray diffraction studies of a DNA gyrase CTD from a species that contains one unique type II topoisomerase. 相似文献
3.
4.
C‐terminal domains of bacterial proteases: structure,function and the biotechnological applications 
下载免费PDF全文
下载免费PDF全文 J. Huang C. Wu D. Liu X. Yang R. Wu J. Zhang C. Ma H. He 《Journal of applied microbiology》2017,122(1):12-22
C‐terminal domains widely exist in the C‐terminal region of multidomain proteases. As a β‐sandwich domain in multidomain protease, the C‐terminal domain plays an important role in proteolysis including regulation of the secretory process, anchoring and swelling the substrate molecule, presenting as an inhibitor for the preprotease and adapting the protein structural flexibility and stability. In this review, the diversity, structural characteristics and biological function of C‐terminal protease domains are described. Furthermore, the application prospects of C‐terminal domains, including polycystic kidney disease, prepeptidase C‐terminal and collagen‐binding domain, in the area of medicine and biological artificial materials are also discussed. 相似文献
5.
6.
Rearrangement of disulfide bonds during the synthesis of α‐conotoxin GI using PhS(O)Ph/CH3SiCl3 oxidation procedure was observed. We have demonstrated that the protecting scheme (order of acetamidomethyl (Acm) and tBu protecting groups) of the Cys residues as well as the reaction time influenced the ratio of the native and the mispaired compounds, while the temperature of the reaction mixture had no significant effect. However, in all cases the nonnative derivative was produced in high amount. The structure of the isomers was identified by the combination of enzymatic digestion and mass spectrometry measurements. We conclude that the air oxidation followed by the application of Tl(tfa)3 for the regioselective formation of disulfide bonds leads up to the appropriate compound in the case of the synthesis of α‐conotoxin GI, while the oxidation procedure using PhS(O)Ph/CH3SiCl3 system resulted in the nonnative disulfide isomer. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88:20–28, 2007. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com. 相似文献
7.
8.
In eukaryotes, histone H1 promotes the organization of polynucleosome filaments into chromatin fibers, thus contributing to the formation of an important structural framework responsible for various DNA transaction processes. The H1 protein consists of a short N-terminal \"nose,\" a central globular domain, and a highly basic C-terminal domain. Structure prediction of the C-terminal domain using fold recognition methods reveals the presence of an HMG-box-like fold. We recently showed by extensive site-directed and deletion mutagenesis studies that a 34 amino acid segment encompassing the three S/TPKK motifs, within the C-terminal domain, is responsible for DNA condensing properties of H1. The position of these motifs in the predicted structure corresponds exactly to the DNA-binding segments of HMG-box-containing proteins such as Lef-1 and SRY. Previous analyses have suggested that histone H1 is likely to bend DNA bound to the C-terminal domain, directing the path of linker DNA in chromatin. Prediction of the structure of this domain provides a framework for understanding the higher order of chromatin organization. 相似文献
9.
10.
Vila R Ponte I Jiménez MA Rico M Suau P 《Protein science : a publication of the Protein Society》2000,9(4):627-636
The structural study of peptides belonging to the terminal domains of histone H1 can be considered as a step toward the understanding of the function of H1 in chromatin. The conformational properties of the peptide Ac-EPKRSVAFKKTKKEVKKVATPKK (CH-1), which belongs to the C-terminal domain of histone H1(o) (residues 99-121) and is adjacent to the central globular domain of the protein, were examined by means of 1H-NMR and circular dichroism. In aqueous solution, CH-1 behaved as a mainly unstructured peptide, although turn-like conformations in rapid equilibrium with the unfolded state could be present. Addition of trifluoroethanol resulted in a substantial increase of the helical content. The helical limits, as indicated by (i,i + 3) nuclear Overhauser effect (NOE) cross correlations and significant up-field conformational shifts of the C(alpha) protons, span from Pro100 to Val116, with Glu99 and Ala117 as N- and C-caps. A structure calculation performed on the basis of distance constraints derived from NOE cross peaks in 90% trifluoroethanol confirmed the helical structure of this region. The helical region has a marked amphipathic character, due to the location of all positively charged residues on one face of the helix and all the hydrophobic residues on the opposite face. The peptide has a TPKK motif at the C-terminus, following the alpha-helical region. The observed NOE connectivities suggest that the TPKK sequence adopts a type (I) beta-turn conformation, a sigma-turn conformation or a combination of both, in fast equilibrium with unfolded states. Sequences of the kind (S/T)P(K/R)(K/R) have been proposed as DNA binding motifs. The CH-1 peptide, thus, combines a positively charged amphipathic helix and a turn as potential DNA-binding motifs. 相似文献
11.
Wendel A. Alves Armando Paduan-Filho Marcos Nogueira Eberlin 《Inorganica chimica acta》2005,358(13):3581-3591
Two mononuclear copper(II) complexes 1 and 2 with the unsymmetrical tridentate ligands 2- and 4-[((imidazol-2-ylmethylidene)amino)ethyl]pyridine have been prepared. In alkaline solution, deprotonation of the imidazole moiety in 1 and 2 promotes self-assembly, which yielded two structurally different species. Depending on the binding site in the imidazole ring, a polymeric complex with an infinite zig-zag-chain 3, or a cyclic-tetranuclear complex 4 is formed, as shown by spectroscopic and spectrometric analysis. Herein, structural characterization of these isomeric polynuclear complexes was performed by electrospray mass (ESI-MS) and tandem mass spectrometric experiments (ESI-MS/MS). Each isomer was shown to be stable in methanolic solutions and to display unique mass spectra with characteristic multiply charged molecular and fragment ions, corroborating previous data by EPR measurements. Magnetic data in the solid state fit a typical curve for an one-dimensional infinite regular chain system, with J = −(32.4 ± 1.2) cm−1 and g = 2.03 for 3, and that of a cyclic-tetranuclear structure with J = −(55.5 ± 0.4) cm−1 and g = 2.29 for 4. In the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) by molecular oxygen, both complexes were shown to act as efficient catalysts, exhibiting very similar ratios: kcat/KM = 9.12 × 106 mol−1 dm3 min−1 for 3 and 8.73 × 106 mol−1 dm3 min−1 for 4. These similar ratios indicate that interactions between the metal centres in 3 or 4 and the substrate in solution occur predominantly at the outside of the catalyst framework. 相似文献
12.
13.
This paper describes a novel approach for the introduction of a C-1 hydroxyl on the decalin ring system, starting from (-)-carvone. Utilizing the substrate-controlled Mukaiyama aldol reaction and alkaline cyclization as key steps, the C-1 oxygenated decalin eudesmane skeleton 2' and its four isomers were synthesized efficiently. Furthermore, X-ray structural analysis showed that the claimed structure for the natural product is incorrect. 相似文献
14.
Kemin Tan Brooke L. Deatherage Kaiser Ruiying Wu Marianne Cuff Yao Fan Lance Bigelow Robert P. Jedrzejczak Joshua N. Adkins John R. Cort Gyorgy Babnigg Andrzej Joachimiak 《Protein science : a publication of the Protein Society》2017,26(9):1738-1748
Salmonella enterica serovar Typhimurium can induce both humoral and cell‐mediated responses when establishing itself in the host. These responses are primarily stimulated against the lipopolysaccharide and major outer membrane (OM) proteins. OmpA is one of these major OM proteins. It comprises a N‐terminal eight‐stranded β‐barrel transmembrane domain and a C‐terminal domain (OmpACTD). The OmpACTD and its homologs are believed to bind to peptidoglycan (PG) within the periplasm, maintaining bacterial osmotic homeostasis and modulating the permeability and integrity of the OM. Here we present the first crystal structures of the OmpACTD from two pathogens: S. typhimurium (STOmpACTD) in open and closed forms and causative agent of Lyme Disease Borrelia burgdorferi (BbOmpACTD), in closed form. In the open form of STOmpACTD, an aspartate residue from a long β2‐α3 loop points into the binding pocket, suggesting that an anion group such as a carboxylate group from PG is favored at the binding site. In the closed form of STOmpACTD and in the structure of BbOmpACTD, a sulfate group from the crystallization buffer is tightly bound at the binding site. The differences between the closed and open forms of STOmpACTD, suggest a large conformational change that includes an extension of α3 helix by ordering a part of β2‐α3 loop. We propose that the sulfate anion observed in these structures mimics the carboxylate group of PG when bound to STOmpACTD suggesting PG‐anchoring mechanism. In addition, the binding of PG or a ligand mimic may enhance dimerization of STOmpACTD, or possibly that of full length STOmpA. 相似文献
15.
Lisa A. Ridnour Sneha Dhanapal Michael Hoos Joan Wilson Jennifer Lee Robert Y. S. Cheng Ernst E. Brueggemann Harry B. Hines Donna M. Wilcock Michael P. Vitek David A. Wink Carol A. Colton 《Journal of neurochemistry》2012,123(5):736-749
Fibrillar amyloid plaques are largely composed of amyloid‐beta (Aβ) peptides that are metabolized into products, including Aβ1‐16, by proteases including matrix metalloproteinase 9 (MMP‐9). The balance between production and degradation of Aβ proteins is critical to amyloid accumulation and resulting disease. Regulation of MMP‐9 and its endogenous inhibitor tissue inhibitor of metalloproteinase (TIMP)‐1 by nitric oxide (NO) has been shown. We hypothesize that nitric oxide synthase (NOS2) protects against Alzheimer's disease pathology by increasing amyloid clearance through NO regulation of MMP‐9/TIMP‐1 balance. We show NO‐mediated increased MMP‐9/TIMP‐1 ratios enhanced the degradation of fibrillar Aβ in vitro, which was abolished when silenced for MMP‐9 protein translation. The in vivo relationship between MMP‐9, NO and Aβ degradation was examined by comparing an Alzheimer's disease mouse model that expresses NOS2 with a model lacking NOS2. To quantitate MMP‐9 mediated changes, we generated an antibody recognizing the Aβ1‐16 fragment, and used mass spectrometry multi‐reaction monitoring assay for detection of immunoprecipitated Aβ1‐16 peptides. Aβ1‐16 levels decreased in brain lysates lacking NOS2 when compared with strains that express human amyloid precursor protein on the NOS2 background. TIMP‐1 increased in the APPSwDI/NOS2?/? mice with decreased MMP activity and increased amyloid burden, thereby supporting roles for NO in the regulation of MMP/TIMP balance and plaque clearance. 相似文献
16.
Calvete JJ Moreno-Murciano MP Sanz L Jürgens M Schrader M Raida M Benjamin DC Fox JW 《Protein science : a publication of the Protein Society》2000,9(7):1365-1373
The disulfide bond pattern of catrocollastatin-C was determined by N-terminal sequencing and mass spectrometry. The N-terminal disintegrin-like domain is a compact structure including eight disulfide bonds, seven of them in the same pattern as the disintegrin bitistatin. The protein has two extra cysteine residues (XIII and XVI) that form an additional disulfide bond that is characteristically found in the disintegrin-like domains of cellular metalloproteinases (ADAMs) and PIII snake venom Zn-metalloproteinases (SVMPs). The C-terminal cysteine-rich domain of catrocollastatin-C contains five disulfide bonds between nearest-neighbor cysteines and a long range disulfide bridge between CysV and CysX. These results provide structural evidence for a redefinition of the disintegrin-like and cysteine-rich domain boundaries. An evolutionary pathway for ADAMs, PIII, and PII SVMPs based on disulfide bond engineering is also proposed. 相似文献
17.
《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):281-289
The per‐O‐acetylated open chain derivatives of 1‐(1‐butylindol‐3‐yl)‐1‐deoxy‐1‐L‐sorbose and 1‐(1‐butylindol‐3‐yl)‐1‐deoxy‐L‐tagatose, which are readily available by alkaline degradation of 1‐butylascorbigen followed by acetylation, were used in a nucleoside‐type synthesis. The interaction of these ketoses derivatives with bis‐(trimethylsilyl)‐uracil yielded in each case a mixture of (E)‐2,4,5,6‐tetra‐O‐acetyl‐1‐(1‐butylindol‐3‐yl)‐1,3‐dideoxy‐3‐(uracil‐1‐yl)‐L‐xylo‐hexa‐1‐enitol and (E)‐2,4,5,6‐tetra‐O‐acetyl‐1‐(1‐butylindol‐3‐yl)‐1,3‐dideoxy‐3‐(uracil‐1‐yl)‐L‐lyxo‐hexa‐1‐enitol, which were separated by preparative HPLC. The deacetylation of each of these compounds by MeONa in MeOH produced a mixture of 1‐(1‐butylindol‐3‐yl)‐1,3‐dideoxy‐4‐O‐methyl‐3‐(uracil‐1‐yl)‐α‐L‐sorbopyranose and 1‐(1‐butylindol‐3‐yl)‐1,3‐dideoxy‐4‐O‐methyl‐3‐(uracil‐1‐yl)‐β‐D‐fructopyranose, which were also separated by HPLC, the structures were confirmed by NMR. 相似文献
18.
The ryanodine receptors (RyR) are essential to calcium signaling in striated muscles, and numerous disease mutations have been identified in two RyR isoforms, RyR1 in skeletal muscle and RyR2 in cardiac muscle. A deep understanding of the activation/regulation mechanisms of RyRs has been hampered by the shortage of high‐resolution structures and dynamic information for this giant tetrameric complex in different functional states. Toward elucidating the molecular mechanisms of disease mutations in RyRs, we performed molecular dynamics simulation of the N‐terminal domain (NTD) which is not only the best‐resolved structural component of RyRs, but also a hotspot of disease mutations. First, we simulated the tetrameric NTD of wild‐type RyR1 and three disease mutants (K155E, R157Q, and R164Q) that perturb the inter‐subunit interfaces. Our simulations identified a dynamic network of salt bridges involving charged residues at the inter‐subunit/subdomain interfaces and disease‐mutation sites. By perturbing this key network, the above three mutations result in greater flexibility with the highest inter‐subunit opening probability for R157Q. Next, we simulated the monomeric NTD of RyR2 in the presence or absence of a central Cl– anion which is known to stabilize the interfaces between the three NTD subdomains (A, B, and C). We found that the loss of Cl– restructures the salt‐bridge network near the Cl–‐binding site, leading to rotations of subdomain A/B relative to subdomain C and enhanced mobility between the subdomains. This finding supports a mechanism for disease mutations in the NTD of RyR2 via perturbation of the Cl– binding. The rich structural and dynamic information gained from this study will guide future mutational and functional studies of the NTD of RyRs. Proteins 2017; 85:1633–1644. © 2017 Wiley Periodicals, Inc. 相似文献
19.
Kusum Vats Rohit Sharma Mythili Kameswaran Haladhar Dev Sarma Drishty Satpati Ashutosh Dash 《Journal of peptide science》2019,25(7)
The present study describes modification of asparagine–glycine–arginine (NGR) peptide at N‐terminally and C‐terminally by introduction of a tridentate chelating scaffold via click chemistry reaction. The N‐terminal and C‐terminal modified peptides were radiometalated with [99mTc(CO)3]+ precursor. The influence of these moieties at the two termini on the targeting properties of NGR peptide was determined by in vitro cell uptake studies and in vivo biodistribution studies. The two radiolabeled constructs did not exhibit any significant variation in uptake in murine melanoma B16F10 cells during in vitro studies. In vivo studies revealed nearly similar tumor uptake of N‐terminally modified peptide construct 5 and C‐terminally construct 6 at 2 h p.i. (1.9 ± 0.1 vs 2.4 ± 0.2% ID/g, respectively). The tumor‐to‐blood (T/B) and tumor‐to‐liver (T/L) ratios of the two radiometalated peptides were also quite similar. The two constructs cleared from all the major organs (heart, lungs, spleen, stomach, and blood) at 4 h p.i. (<1% ID/g). Blocking studies carried out by coinjection of cCNGRC peptide led to approximately 50% reduction in the tumor uptake at 2 h p.i. This work thus illustrates the possibility of convenient modification/radiometalation of NGR peptide at either N‐ or C‐terminus without hampering tumor targeting and pharmacokinetics. 相似文献
20.
An intramolecular charge transfer (ICT) fluorescent sensor 1 using a dansyl moiety as the fluorophore and an azathia-crown ether as the receptor was designed, synthesized and characterized. The ions-selective signaling behaviors of the sensor 1 were investigated in CH(3) CN-H(2) O (1:1, v/v) by fluorescence spectroscopy. It exhibited remarkable fluorescence quenching upon addition of Hg(2+), which was attributed to the 1:1 complex formation between 1 and Hg(2+), while other selected metal ions induced basically no spectral changes. The sensor 1 showed a rapid and linear response towards Hg(2+) in the concentration range from 5.0 × 10(-7) to 1.0 × 10(-5) mol L(-1) with the detection limit of 1.0 × 10(-7) mol L(-1). Furthermore, the whole process could be carried out in a wide pH range of 2.0-8.0 and was not disturbed by other metal ions. Thus, the sensor 1 was used for practical determination of Hg(2+) in different water samples with satisfactory results. 相似文献