排序方式: 共有209条查询结果,搜索用时 18 毫秒
51.
The determination of factors that influence protein conformational changes is very important for the identification of potentially amyloidogenic and disordered regions in polypeptide chains. In our work we introduce a new parameter, mean packing density, to detect both amyloidogenic and disordered regions in a protein sequence. It has been shown that regions with strong expected packing density are responsible for amyloid formation. Our predictions are consistent with known disease-related amyloidogenic regions for eight of 12 amyloid-forming proteins and peptides in which the positions of amyloidogenic regions have been revealed experimentally. Our findings support the concept that the mechanism of amyloid fibril formation is similar for different peptides and proteins. Moreover, we have demonstrated that regions with weak expected packing density are responsible for the appearance of disordered regions. Our method has been tested on datasets of globular proteins and long disordered protein segments, and it shows improved performance over other widely used methods. Thus, we demonstrate that the expected packing density is a useful value with which one can predict both intrinsically disordered and amyloidogenic regions of a protein based on sequence alone. Our results are important for understanding the structural characteristics of protein folding and misfolding. 相似文献
52.
Svitlana Chernii Mykhaylo Losytskyy Anna Kelm Alexandr Gorski Iryna Tretyakova Sergiy Yarmoluk Victor Chernii Vladyslava Kovalska 《Journal of molecular recognition : JMR》2020,33(1)
Amyloid fibrils are rigid β‐pleated protein aggregates that are connected with series of harmful diseases and at the same time are promising as base for novel nanomaterials. Thus, design of compounds able to inhibit or redirect those aggregates formation is important both for the biomedical aims and for nanotechnology applications. Here, we studied the effect of tetraphenylporphyrins (metal free, their Cu and Pd complexes, and those functionalized by carboxy and amino groups on periphery) on insulin amyloid self‐assembling. The strongest impact on insulin aggregation was demonstrated by a metal‐free porphyrin bearing four carboxy groups. This compound strongly suppresses insulin aggregation (about 88% reduction in amyloid‐sensitive probe emission) inducing formation of fibrils with the length close to this of free insulin (1.7 ± 0.6 μm as compared with 1.4 ± 0.4 μm, respectively) with an essentially reduced tendency to lateral aggregation. Contrarily, the presence of tetraphenylporphyrin containing four amino groups only slightly affects fibrils' morphology and makes weaker impact on insulin aggregation yield (about 44% reduction). This is explained by the ability of aromatic carboxy groups of 5,10,15,20‐(tetra‐4‐carboxyphenyl)porphyrin to interact with complementary protein‐binding groups and thus stabilize the supramolecular complex. For 5,10,15,20‐(tetra‐4‐aminophenyl)porphyrin, full protonation takes place in acidic medium of protein aggregation reaction; this results in the high positive charge of TPPN4 (equal or close to +6) and hence higher contribution of coulombic repulsion to interaction of TPPN4 with insulin. One more possible mechanism of the lower inhibition effect of TPPN4 as compared with TPPC4 could be the more restricted possibility of the former as compared with the latter to form H bonds with insulin groups. It was also shown that metal‐free, Pd‐containing, and Cu‐containing tetraphenylporphyrins without peripheral substituents make almost the same impact on the protein self‐assembling. We suppose this to be due to coordination saturation of these metal atoms. 相似文献
53.
54.
Michael Ibrahim Punam Kukadia Urszula Siedlecka James E. Cartledge Manoraj Navaratnarajah Sergiy Tokar Carin Van Doorn Victor T. Tsang Julia Gorelik Magdi H. Yacoub Cesare M. Terracciano 《Journal of cellular and molecular medicine》2012,16(12):2910-2918
Cardiac transverse (t)‐tubules are altered during disease and may be regulated by stretch‐sensitive molecules. The relationship between variations in the degree and duration of load and t‐tubule structure remains unknown, as well as its implications for local Ca2+‐induced Ca2+ release (CICR). Rat hearts were studied after 4 or 8 weeks of moderate mechanical unloading [using heterotopic abdominal heart–lung transplantation (HAHLT)] and 6 or 10 weeks of pressure overloading using thoracic aortic constriction. CICR, cell and t‐tubule structure were assessed using confocal‐microscopy, patch‐clamping and scanning ion conductance microscopy. Moderate unloading was compared with severe unloading [using heart‐only transplantation (HAHT)]. Mechanical unloading reduced cardiomyocyte volume in a time‐dependent manner. Ca2+ release synchronicity was reduced at 8 weeks moderate unloading only. Ca2+ sparks increased in frequency and duration at 8 weeks of moderate unloading, which also induced t‐tubule disorganization. Overloading increased cardiomyocyte volume and disrupted t‐tubule morphology at 10 weeks but not 6 weeks. Moderate mechanical unloading for 4 weeks had milder effects compared with severe mechanical unloading (37% reduction in cell volume at 4 weeks compared to 56% reduction after severe mechanical unloading) and did not cause depression and delay of the Ca2+ transient, increased Ca2+ spark frequency or impaired t‐tubule and cell surface structure. These data suggest that variations in chronic mechanical load influence local CICR and t‐tubule structure in a time‐ and degree‐dependent manner, and that physiological states of increased and reduced cell size, without pathological changes are possible. 相似文献
55.
The interactions between an oligomeric heat-shock protein, alpha-crystallin, and its individual subunits with unfolded proteins were monitored by surface plasmon resonance. Immobilization at the sensor chip allowed us for the first time to study isolated alpha-crystallin subunits under physiological conditions. We observe that these subunits, in contrast to alpha-crystallin oligomers, do not bind unfolded protein. Our data indicate that quaternary structure of alpha-crystallin is necessary for its chaperone-like activity. 相似文献
56.
Involvement of mtDNA damage in free fatty acid-induced apoptosis 总被引:5,自引:0,他引:5
Grishko V Rachek L Musiyenko S Ledoux SP Wilson GL 《Free radical biology & medicine》2005,38(6):755-762
A growing body of evidence indicates that free fatty acids (FFA) can have deleterious effects on beta-cells. It has been suggested that the beta-cell dysfunction and death observed in diabetes may involve exaggerated activation of the inducible form of nitric oxide synthase (iNOS) by FFA, with the resultant generation of excess nitric oxide (NO). However, the cellular targets with which NO interact have not been fully identified. We hypothesized that one of these targets might be mitochondrial DNA (mtDNA). Therefore, experiments were initiated to evaluate damage to mtDNA caused by exposure of INS-1 cells to FFA (2/1 oleate/palmetate). The results showed that FFA caused a dose-dependent increase in mtDNA damage. Additionally, using ligation-mediated PCR, we were able to show that the DNA damage pattern at the nucleotide level was identical to the one induced by pure NO and different from damage caused by peroxynitrite or superoxide. Following exposure to FFA, apoptosis was detected by DAPI staining and cytochrome c release. Treatment of INS-1 cells with the iNOS inhibitor aminoguanidine protected these cells from mtDNA damage and diminished the appearance of apoptosis. These studies suggest that mtDNA may be a sensitive target for NO-induced toxicity which may provoke apoptosis in beta-cells following exposure to FFA. 相似文献
57.
Torsten H. Walther Christina Gottselig Stephan L. Grage Moritz Wolf Attilio V. Vargiu Marco J. Klein Stefanie Vollmer Sebastian Prock Mareike Hartmann Sergiy Afonin Eva Stockwald Hartmut Heinzmann Olga V. Nolandt Wolfgang Wenzel Paolo Ruggerone Anne S. Ulrich 《Cell》2013,152(1-2):316-326
Highlights? Charge zippers as a new concept for folding and assembly of membrane proteins ? 3D structure of TatA pore explains translocation of folded proteins across membrane ? Ladders of salt bridges connect an amphiphilic palisade that can span the bilayer ? MD simulations and specific charge mutations support the charge zipper model 相似文献
58.
Mark P. Little Tamara V. Azizova Dimitry Bazyka Simon D. Bouffler Elisabeth Cardis Sergey Chekin Vadim V. Chumak Francis A. Cucinotta Florent de Vathaire Per Hall John D. Harrison Guido Hildebrandt Victor Ivanov Valeriy V. Kashcheev Sergiy V. Klymenko Olivier Laurent Kotaro Ozasa Soile Tapio Andrew M. Taylor Ioanna Tzoulaki Wendy L. Vandoolaeghe Richard Wakeford Lydia Zablotska Wei Zhang Steven E. Lipshultz 《Radiation and environmental biophysics》2013,52(1):157-159
59.
Kevin Hannigan Shridhar S. Kulkarni Volodymyr G. Bdzhola Andriy G. Golub Sergiy M. Yarmoluk Tanaji T. Talele 《Bioorganic & medicinal chemistry letters》2013,23(21):5790-5794
Poly(ADP-ribose)polymerase-1 (PARP-1) is an abundant and ubiquitous chromatin-bound nuclear protein. PARP-1, a DNA repair enzyme, has been in the limelight as a chemotherapeutic target. In this study, we demonstrated the successful use of structure-based virtual screening to identify inhibitors of PARP-1 from Otava databases comprised of nearly 260,000 compounds. Five novel inhibitors belonging to thienopyrimidinone, isoquinolinoquinazolinone, pyrroloquinazolinone, and cyclopentenothienopyrimidinone scaffolds revealed inhibitory potencies with IC50 values ranged from 9.57 μM to 0.72 μM. Structural features relevant to the activity of these novel compounds within the active site of PARP-1 are discussed in detail and will guide future SAR investigation on these scaffolds. 相似文献
60.
Golub AG Bdzhola VG Kyshenia YV Sapelkin VM Prykhod'ko AO Kukharenko OP Ostrynska OV Yarmoluk SM 《Molecular and cellular biochemistry》2011,356(1-2):107-115
Serine/threonine protein kinase CK2 controls vast variety of fundamental processes in cell life; however, despite long period of study, its functional role is not completely determined. CK2 has a significant pathogenic potential and its activity is strictly associated with the development of various kinds of disorders. There are a growing number of facts that inhibitors of CK2 could be used as pharmaceutical agents for the cancer treatment, viral infections, and inflammatory diseases. In this article, we report structural and biological data on the novel synthetic flavonol derivatives, 3-hydroxy-4'-carboxyflavones, possessing a high inhibitory activity toward CK2. With the aid of combinatorial organic synthesis, molecular modeling techniques and biochemical in vitro tests, we studied the structure-activity relationships of flavonol derivatives and developed binding model describing their key intermolecular interactions with the CK2 ATP-binding site. Obtained data show that the synthetic 3-hydroxy-4'-carboxyflavones possess the highest activity among flavonol inhibitors of CK2 known till date. 相似文献