排序方式: 共有53条查询结果,搜索用时 279 毫秒
1.
Angela Lombardi Michele Saviano Flavia Nastri Ornella Maglio Marco Mazzeo Carlo Pedone Carla Isernia Vincenzo Pavone 《Biopolymers》1996,38(6):683-691
In the present paper we describe the synthesis, purification, and single crystal x-ray analysis of the cyclic pentapeptide cyclo-(Pro-Phe-Phe-β-Ala-β-Ala). This compound crystallizes in the orthorhombic space group P212121 from methanol and adopts in the solid state an unusual conformation characterized by a cis β-Ala5-Pro1 peptide bond and by an intramolecular hydrogen bond stabilizing a C11- and a C12-ring structure. The C11, structure contains the Phe3 and the β-Ala4 at the corner position of the turn; it is the first observation of a type II β-turn enlargement due to the insertion of an extra methylene group of the β-alanine residue. The rest of the molecule participates in a newly characterized C12-ring structure, which incorporates a β-Ala residue at position i of the turn. © 1996 John Wiley & Sons, Inc. 相似文献
2.
R. Fattorusso G. Morelli A. Lombardi F. Nastri O. Maglio G. D'Auria C. Pedone V. Pavone 《Biopolymers》1995,37(6):401-410
Two cyclic and branched peptides (PLA and AZU) were synthesized with the aim of reproducing the active site of the blue copper proteins plastocyanin and azurin. Both peptides, designed on the basis of the x-ray structures of Poplar plastocyanin and Alcaligenes denitrificans azurin. contain the same coordinating residues of the parent native proteins. The visible spectra of PLA in the presence of equimolar amount of Cu(II) strongly support the interaction between the peptide and copper(II) ion. The CD titration of AZU with the Hg(II) ion indicates for the formation of two species. [A ZUHg]+ and [A ZUHg2]3+ having binding constants (Keq) of 3.106 and 2–104M?1, respectively. © 1994 John Wiley & Sons, Inc. 相似文献
3.
4.
Alcohol consumption and alcohol problems after bariatric surgery in the swedish obese subjects study
5.
Rafael Torres Martin de Rosales Marina Faiella Erik Farquhar Lawrence Que Jr Concetta Andreozzi Vincenzo Pavone Ornella Maglio Flavia Nastri Angela Lombardi 《Journal of biological inorganic chemistry》2010,15(5):717-728
The design, synthesis, and metal-binding properties of DF3, a new de novo designed di-iron protein model are described (“DF”
represents due ferri, Italian for “two iron,” “di-iron”). DF3 is the latest member of the DF family of synthetic proteins. They consist of helix–loop–helix
hairpins, designed to dimerize and form an antiparallel four-helix bundle that encompasses a metal-binding site similar to
those of non-heme carboxylate-bridged di-iron proteins. Unlike previous DF proteins, DF3 is highly soluble in water (up to
3 mM) and forms stable complexes with several metal ions (Zn, Co, and Mn), with the desired secondary structure and the expected
stoichiometry of two ions per protein. UV–vis studies of Co(II) and Fe(III) complexes confirm a metal-binding environment
similar to previous di-Co(II)- and di-Fe(III)-DF proteins, including the presence of a μ-oxo-di-Fe(III) unit. Interestingly,
UV–vis, EPR, and resonance Raman studies suggest the interaction of a tyrosine adjacent to the di-Fe(III) center. The design
of DF3 was aimed at increasing the accessibility of small molecules to the active site of the four-helix bundle. Indeed, binding
of azide to the di-Fe(III) site demonstrates a more accessible metal site compared with previous DFs. In fact, fitting of
the binding curve to the Hill equation allows us to quantify a 150% accessibility enhancement, with respect to DF2. All these
results represent a significant step towards the development of a functional synthetic DF metalloprotein. 相似文献
6.
Fluur C De Milito A Fry TJ Vivar N Eidsmo L Atlas A Federici C Matarrese P Logozzi M Rajnavölgyi E Mackall CL Fais S Chiodi F Rethi B 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(8):5340-5350
IL-7 promotes survival of resting T lymphocytes and induces T cell proliferation in lymphopenic conditions. As elevated IL-7 levels occur in HIV-infected individuals in addition to high Fas expression on T cells and increased sensitivity to Fas-induced apoptosis, we analyzed whether IL-7 has a regulatory role in Fas-mediated T cell apoptosis. We show that IL-7 up-regulates Fas expression on naive and memory T cells through a mechanism that involves translocation of Fas molecules from intracellular compartments to the cell membrane. IL-7 induced the association of Fas with the cytoskeletal component ezrin and a polarized Fas expression on the cell surface. The potential role of IL-7 in Fas up-regulation in vivo was verified in IL-7-treated macaques and in HIV-infected or chemotherapy treated patients by the correlation between serum IL-7 levels and Fas expression on T cells. IL-7 treatment primed T cells for Fas-induced apoptosis in vitro and serum IL-7 levels correlated with the sensitivity of T cells to Fas-induced apoptosis in HIV-infected individuals. Our data suggest an important role for IL-7 in Fas-mediated regulation of T cell homeostasis. Elevated IL-7 levels associated with lymphopenic conditions, including HIV-infection, might participate in the increased sensitivity of T cells for activation-induced apoptosis. 相似文献
7.
De novo protein design provides an attractive approach for the construction of models to probe the features required for the function of complex metalloproteins. These minimal models contain the essential elements believed necessary for activity of the protein. In this article, we summarize the design, structure determination, and functional properties of a family of artificial diiron proteins. 相似文献
8.
Vincenzo Pavone Angelina Lombardi Michele Saviano Benedetto Di Blasio Flavia Nastri Roberto Fattorusso Ornella Maglio Carla Isernia 《Biopolymers》1994,34(11):1505-1515
In the present paper we describe the synthesis, purification, single crystal x-ray analysis, and solution structural characterization by nmr spectroscopy, combined with restrained molecular dynamic simulations, of the cyclic hexapeptide cyclo-(Pro-Phe-β-Ala-Phe-Phe-β-Ala). The peptide was synthesized by classical solution methods and the cyclization of the free hexapeptide was accomplished in good yields in diluted methylenechloride solution using N, N-dicyclohexyl-carbodiimide. The compound crystallizes in the monoclinic space group P21 from methanol/ethyl acetate. The molecule adopts in the solid state a conformation characterized by cis β-Ala6-Pro1 peptide bond. The α-amino acid residues are at the corner positions of turned structures. The Pro1-Phe2 segment is incorporated in a pseudo type I β-turn, while Phe4-Phe5 is in a typical type I β-turn. Assignment of all 1H and 13C resonances was achieved by homo- and heteronuclear two-dimensional techniques in dimethylsulfoxide (DMSO) solutions. The conformational analysis was based on inter-proton distances derived from rotating frame nuclear Overhauser effect spectroscopy spectra and homonuclear coupling constants. Restrained molecular dynamic simulation in vacuo was also performed to built refined molecular models. The molecule is present in DMSO solution as two slowly interconverting conformers, characterized by a cis-tran isomerism around the β-Ala6-Pro1 peptide bond. This work confirms our expectations on the low propensity of β-alanyl residues to be positioned at the corners of turned structure. © 1994 John Wiley & Sons, Inc. 相似文献
9.
10.
D. Bellavia L. Raimondi V. Costa A. De Luca V. Carina M. Maglio M. Fini R. Alessandro G. Giavaresi 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1893-1901