全文获取类型
收费全文 | 270篇 |
免费 | 20篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 11篇 |
2012年 | 19篇 |
2011年 | 24篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 15篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 29篇 |
2002年 | 24篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有290条查询结果,搜索用时 15 毫秒
61.
Cristina Sensi Sara Simonelli Ilaria Zanotti Gabriella Tedeschi Giulia Lusardi Guido Franceschini Laura Calabresi Ivano Eberini 《PloS one》2014,9(4)
LCAT (lecithin:cholesterol acyltransferase) catalyzes the transacylation of a fatty acid of lecithin to cholesterol, generating a cholesteryl ester and lysolecithin. The knowledge of LCAT atomic structure and the identification of the amino acids relevant in controlling its structure and function are expected to be very helpful to understand the enzyme catalytic mechanism, as involved in HDL cholesterol metabolism. However - after an early report in the late ‘90 s - no recent advance has been made about LCAT three-dimensional structure. In this paper, we propose an LCAT atomistic model, built following the most up-to-date molecular modeling approaches, and exploiting newly solved crystallographic structures. LCAT shows the typical folding of the α/β hydrolase superfamily, and its topology is characterized by a combination of α-helices covering a central 7-strand β-sheet. LCAT presents a Ser/Asp/His catalytic triad with a peculiar geometry, which is shared with such other enzyme classes as lipases, proteases and esterases. Our proposed model was validated through different approaches. We evaluated the impact on LCAT structure of some point mutations close to the enzyme active site (Lys218Asn, Thr274Ala, Thr274Ile) and explained, at a molecular level, their phenotypic effects. Furthermore, we devised some LCAT modulators either designed through a de novo strategy or identified through a virtual high-throughput screening pipeline. The tested compounds were proven to be potent inhibitors of the enzyme activity. 相似文献
62.
Ilaria?Bartalesi Ivano?BertiniEmail author Giulia?Di?Rocco Antonio?Ranieri Antonio?Rosato Murugendra?Vanarotti Paul?R.?Vasos Maria?Silvia?Viezzoli 《Journal of biological inorganic chemistry》2004,9(5):600-608
The minimal mono-heme ferricytochrome
c from Bacillus pasteurii, containing 71 amino acids, has been further investigated through mutagenesis of different positions in the loop containing the iron ligand Met71. These mutations have been designed to sample different aspects of the loop structure, in order to obtain insights into the determinants of the stability of the iron(III) environment. In particular, positions 68, 72 and 75 have been essayed. Gln68 has been mutated to Lys to provide a suitable alternate ligand that can displace Met71 under denaturing conditions. Pro72 has been mutated to Gly and Ala to modify the range of allowed backbone conformations. Ile75, which is in van der Waals contact with Met71 and partly shields a long-lived water molecule in a protein cavity, has been substituted by Val and Ala to affect the network of inter-residue interactions around the metal site. The different contributions of the above amino acids to protein parameters such as structure, redox potential and the overall stability against unfolding with guanidinium hydrochloride are analyzed. While the structure remains essentially the same, the stability decreases with mutations. The comparison with mitochondrial c-type cytochromes is instructive.Abbreviations Bpcytc
soluble fragment of cytochrome c553 from Bacillus pasteurii
- GdmCl
guanidinium chloride
- I75A
Ile75 to Ala mutant
- I75V
Ile75 to Val mutant
- P72A
Pro72 to Ala mutant
- P72G
Pro72 to Gly mutant
- Q68K
Gln75 to Lys mutant
- WT
wild type 相似文献
63.
64.
65.
Ivano Brunner 《Trees - Structure and Function》1991,5(2):90-94
Summary Various in vitro synthesis techniques with Picea abies and two Hebeloma species showed that structures of the mantle and Hartig net of synthesized ectomycorrhizae within the given two fungus species are stable. However, thickness of mantle, and penetration depth and number of hyphal cell rows between cortical cells of the Hartig net are dependent on techniques and substrates. Porous glass balls as substrate in the Erlenmeyer technique seem to suppress or delay mantle and Hartig net formation. With the other techniques (growth pouch, open cuvette, Erlenmeyer with a vermiculite-peat moss mixture) development of the mantle is simultaneous with or shortly in advance of Hartig net formation. The ectomycorrhizae of the two tested Hebeloma species are similar and cannot be morphologically differentiated by the in vitro techniques used. 相似文献
66.
Luca Ciacci Tim T. Werner Ivano Vassura Fabrizio Passarini 《Journal of Industrial Ecology》2019,23(2):426-437
With increased understanding of the effects of human activities on the environment and added awareness of the increasing societal value of natural resources, researchers have begun to focus on the characterization of elemental cycles. Indium has captured significant attention due to the potential for supply shortages and nonexistent recycling at end of life. Such a combination of potentially critical features is magnified for countries that depend on imports of indium, notably many European countries. With the aims of analyzing the dynamics of material flows and of estimating the magnitude of secondary indium sources available for recycling, the anthropogenic indium cycle in Europe has been investigated by material flow analysis. The results showed that the region is a major consumer of finished goods containing indium, and the cumulative addition of indium in urban mines was estimated at about 500 tonnes of indium. We discuss these results from the perspective of closing the metal cycle in the region. Securing access to critical raw materials is a priority for Europe, but the preference for recycling metal urban mines risks to remain only theoretical for indium unless innovations in waste collection and processing unlock the development of technologies that are economically feasible and environmentally sustainable. 相似文献
67.
Bertini I Ferella L Luchinat C Parigi G Petoukhov MV Ravera E Rosato A Svergun DI 《Journal of biomolecular NMR》2012,53(4):271-280
The MaxOcc web portal is presented for the characterization of the conformational heterogeneity of two-domain proteins, through the calculation of the Maximum Occurrence that each protein conformation can have in agreement with experimental data. Whatever the real ensemble of conformations sampled by a protein, the weight of any conformation cannot exceed the calculated corresponding Maximum Occurrence value. The present portal allows users to compute these values using any combination of restraints like pseudocontact shifts, paramagnetism-based residual dipolar couplings, paramagnetic relaxation enhancements and small angle X-ray scattering profiles, given the 3D structure of the two domains as input. MaxOcc is embedded within the NMR grid services of the WeNMR project and is available via the WeNMR gateway at http://py-enmr.cerm.unifi.it/access/index/maxocc . It can be used freely upon registration to the grid with a digital certificate. 相似文献
68.
Bertini I Felli IC Gonnelli L Pierattelli R Spyranti Z Spyroulias GA 《Journal of biomolecular NMR》2006,36(2):111-122
The copper-mediated protein–protein interaction between yeast Atx1 and Ccc2 has been examined by protonless heteronuclear NMR and compared with the already available 1H–15N HSQC information. The observed chemical shift variations are analyzed with respect to the actual solution structure, available
through intermolecular NOEs. The advantage of using the CON-IPAP spectrum with respect to the 1H–15N HSQC resides in the increased number of signals observed, including those of prolines. CBCACO-IPAP experiments allow us
to focus on the interaction region and on side-chain carbonyls, while a newly designed CEN-IPAP experiment on side-chains
of lysines. An attempt is made to rationalize the chemical shift variations on the basis of the structural data involving
the interface between the proteins and the nearby regions. It is here proposed that protonless
13C direct-detection NMR is a useful complement to 1H based NMR spectroscopy for monitoring protein–protein and protein–ligand interactions.
Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at 相似文献
69.
Nadine Grisel Stefan Zoller Marzanna Künzli-Gontarczyk Thomas Lampart Martin Münsterkötter Ivano Brunner Lucien Bovet Jean-Pierre Métraux Christoph Sperisen 《BMC plant biology》2010,10(1):185
Background
Ionic aluminum (mainly Al3+) is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula) releases citrate and oxalate from roots in response to Al exposure. To obtain further insights into the root responses of aspen to Al, we investigated root gene expression at Al conditions that inhibit root growth. 相似文献70.
Lucia Banci Ivano Bertini Francesca Cantini Sayaka Inagaki Manuele Migliardi Antonio Rosato 《The Journal of biological chemistry》2010,285(4):2537-2544
We report the solution NMR structures of the N-domain of the Menkes protein (ATP7A) in the ATP-free and ATP-bound forms. The structures consist of a twisted antiparallel six-stranded β-sheet flanked by two pairs of α-helices. A protein loop of 50 amino acids located between β3 and β4 is disordered and mobile on the subnanosecond time scale. ATP binds with an affinity constant of (1.2 ± 0.1) × 104 m−1 and exchanges with a rate of the order of 1 × 103 s−1. The ATP-binding cavity is considerably affected by the presence of the ligand, resulting in a more compact conformation in the ATP-bound than in the ATP-free form. This structural variation is due to the movement of the α1-α2 and β2-β3 loops, both of which are highly conserved in copper(I)-transporting PIB-type ATPases. The present structure reveals a characteristic binding mode of ATP within the protein scaffold of the copper(I)-transporting PIB-type ATPases with respect to the other P-type ATPases. In particular, the binding cavity contains mainly hydrophobic aliphatic residues, which are involved in van der Waal''s interactions with the adenine ring of ATP, and a Glu side chain, which forms a crucial hydrogen bond to the amino group of ATP. 相似文献