排序方式: 共有238条查询结果,搜索用时 15 毫秒
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Kowal P Gurtan AM Stuckert P D'Andrea AD Ellenberger T 《The Journal of biological chemistry》2007,282(3):2047-2055
Fanconi anemia (FA) is a rare autosomal recessive and X-linked chromosomal instability disorder. At least eight FA proteins (FANCA, B, C, E, F, G, L, and M) form a nuclear core complex required for monoubiquitination of a downstream protein, FANCD2. The human FANCF protein reportedly functions as a molecular adaptor within the FA nuclear complex, bridging between the subcomplexes A:G and C:E. Our x-ray crystallographic studies of the C-terminal domain of FANCF reveal a helical repeat structure similar to the Cand1 regulator of the Cul1-Rbx1-Skp1-Fbox(Skp2) ubiquitin ligase complex. Two C-terminal loops of FANCF are essential for monoubiquitination of FANCD2 and normal cellular resistance to the DNA cross-linking agent mitomycin C. FANCF mutants bearing amino acid substitutions in this C-terminal surface fail to interact with other components of the FA complex, indicating that this surface is critical for the proper assembly of the FA core complex. 相似文献
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Li XP Grela P Krokowski D Tchórzewski M Tumer NE 《The Journal of biological chemistry》2010,285(53):41463-41471
Ribosome inactivating proteins (RIPs) depurinate a universally conserved adenine in the α-sarcin/ricin loop (SRL) and inhibit protein synthesis at the translation elongation step. We previously showed that ribosomal stalk is required for depurination of the SRL by ricin toxin A chain (RTA). The interaction between RTA and ribosomes was characterized by a two-step binding model, where the stalk structure could be considered as an important interacting element. Here, using purified yeast ribosomal stalk complexes assembled in vivo, we show a direct interaction between RTA and the isolated stalk complex. Detailed kinetic analysis of these interactions in real time using surface plasmon resonance (SPR) indicated that there is only one type of interaction between RTA and the ribosomal stalk, which represents one of the two binding steps of the interaction with ribosomes. Interactions of RTA with the isolated stalk were relatively insensitive to salt, indicating that nonelectrostatic interactions were dominant. We compared the interaction of RTA with the full pentameric stalk complex containing two pairs of P1/P2 proteins with its interaction with the trimeric stalk complexes containing only one pair of P1/P2 and found that the rate of association of RTA with the pentamer was higher than with either trimer. These results demonstrate that the stalk is the main landing platform for RTA on the ribosome and that pentameric organization of the stalk accelerates recruitment of RTA to the ribosome for depurination. Our results suggest that multiple copies of the stalk proteins might also increase the scavenging ability of the ribosome for the translational GTPases. 相似文献
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Anna Jurkiewicz Przemyslaw Ryszka Teresa Anielska Piotr Waligórski Dobroslawa Białońska Katarzyna Góralska Merope Tsimilli-Michael Katarzyna Turnau 《Mycorrhiza》2010,20(5):293-306
Arnica montana is a rare plant that needs special protection because of its intensive harvesting for medicinal purposes. The present work
was aimed at finding optimal culture conditions for Arnica plants in order to enable their successful reintroduction into their natural stands. Plants were cultivated under controlled
greenhouse conditions on substrata with different nitrogen (N) concentration. As Arnica is always colonized by arbuscular mycorrhizal fungi (AMF) in nature, a fact that has been overlooked in other similar projects,
we, here, applied and tested different inocula. We found that they differed in their effectiveness, both in establishing symbiosis,
assessed by the colonization parameters, and in improving the performance of Arnica, evaluated by the photosynthetic parameters derived from the fluorescence transients (JIP-test), with the inocula containing
G. intraradices or composed of several Glomus strains being the most effective. The comparison was possible only on substrata with medium N, since high N did not permit
the formation of mycorrhiza, while at low N, few nonmycorrhizal plants survived until the measurements and mycorrhizal plants,
which were well growing, exhibited a high heterogeneity. Analysis of secondary metabolites showed clearly that mycorrhization
was associated with increased concentrations of phenolic acids in roots. For some of the inocula used, a tendency for increase
of the level of phenolic acids in shoots and of sesquiterpene lactones, both in roots and in shoots, was also observed. We
also studied the interactions between A. montana and Dactylis glomerata, known to compete with Arnica under field conditions. When specimens from both species were cultured together, there was no effect on D. glomerata, but Arnica could retain a photosynthetic performance that permitted survivability only in the presence of AMF; without AMF, the photosynthetic
performance was lower, and the plants were eventually totally outcompeted. 相似文献
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Sapieha P Sirinyan M Hamel D Zaniolo K Joyal JS Cho JH Honoré JC Kermorvant-Duchemin E Varma DR Tremblay S Leduc M Rihakova L Hardy P Klein WH Mu X Mamer O Lachapelle P Di Polo A Beauséjour C Andelfinger G Mitchell G Sennlaub F Chemtob S 《Nature medicine》2008,14(10):1067-1076
Vascularization is essential for tissue development and in restoration of tissue integrity after an ischemic injury. In studies of vascularization, the focus has largely been placed on vascular endothelial growth factor (VEGF), yet other factors may also orchestrate this process. Here we show that succinate accumulates in the hypoxic retina of rodents and, via its cognate receptor G protein-coupled receptor-91 (GPR91), is a potent mediator of vessel growth in the settings of both normal retinal development and proliferative ischemic retinopathy. The effects of GPR91 are mediated by retinal ganglion neurons (RGCs), which, in response to increased succinate levels, regulate the production of numerous angiogenic factors including VEGF. Accordingly, succinate did not have proangiogenic effects in RGC-deficient rats. Our observations show a pathway of metabolite signaling where succinate, acting through GPR91, governs retinal angiogenesis and show the propensity of RGCs to act as sensors of ischemic stress. These findings provide a new therapeutic target for modulating revascularization. 相似文献