138,688 research outputs found
The relationship of the ADP-ribosylating enzyme from S. solfataricus with DING proteins and its intracellular localization
No full textThe PARPSso thermoprotein from Sulfolobus solfataricus has been identified as a PARP-like enzyme that cleaves -NAD+ to synthesize oligomers of ADP-ribose and cross-reacts with polyclonal anti-PARP-1 catalytic site antibodies. Despite the biochemical properties that allow to correlate it to PARP enzymes, the N-terminal and partial amino acid sequence suggest the sulfolobal enzyme belongs to a different class of enzymes, the DING proteins. Considering the high sequence identity with the human DING protein HPBP and the lack of a nucleotide coding sequence in both human and sulfolobal genomes, we hypothesized that PARPSso might share other features with the human DING. Further analysis of PARPSso amino acid sequence addressed the research towards studying other possible similarities between human and sulfolobal protein and then to explain how PARPSso correlates with canonic PARPs. For the latter question, the peculiar behaviour of the thermozyme, that is biochemically, but not structurally related to the classic PARPs, stimulated to investigate by computational analysis and databank, whether the protein might be phylogenetically related to any already known PARP amino acid sequence.
Moreover, immunochemical and enzymatic crossed analyses were performed to establish whether purified HPBP and PARPSso have common immunoreactive and functional behaviour.
The second part of the research was focused on the localization of PARPSso within the sulfolobal cell. Our interest to this item arose from the property of some DING proteins to be membrane bound, suggested to work as membrane transporters. On the other hand, from previous studies, it is known that PARPSso is only partially solubilized from the starting cell homogenate provided by ICMIB (CNR), and the soluble enzyme is strictly associated with DNA. In this thesis work, whole cells collected by centrifugation from culture medium were subjected to a different extraction procedure. This procedure included also experimental conditions used to differentiate between soluble (i.e. cytoplasmic) and insoluble (i.e. membrane-bound) protein fractions. PARPSso and DNA distributions were determined by enzyme assay, immunoblotting and agarose gel electrophoresis. Reciprocal interactions of thermozyme, nucleic acid and membrane lipids were investigated with different techniques and methodologies (nucleoid preparation, fluorescence binding assays, fluorescence microscopy analysis)
Synthesis, structure, and properties of [nacnac]MX3 compounds (M = Ge, Sn; X = Cl, Br, I)
No full textReactions of [nacnac]Li [(2,6-(Pr2C6H3)-Pr-i)NC(Me) C(H)C(Me)N(2,6-(Pr2C6H3)-Pr-i)]Li (1) with SnX4 (X = Cl, Br, I) and GeCl4 in Et2O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX3 compounds (X = Cl 2, Br 3, 1 4) the tin atom is five coordinated and part of a six membered ring. The Sn-N-bond length of 3 is 2.163(4)Angstrom and 2.176(5) Angstrom of 4. The five coordinated germanium of the [nacnac]GeCl3 compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon-metal-bond (1.971(3)Angstrom) forming a four-membered ring. The Ge-N bond length (2.319(2) Angstrom) indicates the formation of a weakly coordinating bond
Synthesis, structure, and properties of [nacnac]MX3 compounds (M = Ge, Sn; X = Cl, Br, I)
No full textReactions of [nacnac]Li [(2,6-(Pr2C6H3)-Pr-i)NC(Me) C(H)C(Me)N(2,6-(Pr2C6H3)-Pr-i)]Li (1) with SnX4 (X = Cl, Br, I) and GeCl4 in Et2O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX3 compounds (X = Cl 2, Br 3, 1 4) the tin atom is five coordinated and part of a six membered ring. The Sn-N-bond length of 3 is 2.163(4)Angstrom and 2.176(5) Angstrom of 4. The five coordinated germanium of the [nacnac]GeCl3 compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon-metal-bond (1.971(3)Angstrom) forming a four-membered ring. The Ge-N bond length (2.319(2) Angstrom) indicates the formation of a weakly coordinating bond
Ding - vešč'
No full textGünther H. Ding - vešč'. In: Flaker A, ed. Glossarium der russischen Avantgarde. Graz: Droschl; 1989: 179-187
Synthesis and structures of germanium(II) fluorides and hydrides
No full textTreatment of [{HC(CMeNAr)(2)}GeCl] (Ar = 2,6-iPr(2)C(6)H(3) (1), 2,6-Me2C6H3 (2)) with Me-3-SnF in dichloromethane at room temperature afforded the corresponding fluoride [{HC(CMeNAr)(2)}GeF] (Ar = 2,6-iPr(2)C(6)H(3) (3), 2,6-Me2C6H3 (4)), while with NaBH4 in THF under reflux for 12 h gave the hydride [{HC(CMeNAr)(2)}GeH(BH3)] (Ar = 2,6-iPr(2)C(6)H(3) (5), 2,6-Me2C6H3 (6)). Reaction of 3 with Me3SiN3 in toluene provided [{HC(CMeNAr)(2)}Ge(F)NSiMe3] (Ar = 2,6-iPr(2)C(6)H(3) (7)). The BH3 in 5 can be removed with Me3P to afford [{HC(CMeNAr)(2)}-GeH] (Ar = 2,6-iPr(2)C(6)H(3) (8)), Treatment of 5 with tBuLi in diethyl ether led to [{HC(C(CH2)-NAr)CMeNAr}Ge(H)BH3]Li(Et2O)(3) (Ar = 2,6-iPr(2)C(6)H(3) (9)), in which a hydrogen of one of the Me groups was eliminated, and this consequently resulted in the formation of a methylene group. Compounds 3-6 are the first examples of structurally characterized germanium(II) fluorides and hydrides. Single-crystal X-ray structural analyses indicate that compounds 3, 5, and 9 are monomeric and the germanium center resides in a trigonal-pyramidal environment in 3 and in distorted-tetrahedral environments in 5 and 9
Another remark on a result of Ding-Jost-Li-Wang
Get PDFLet be a compact Riemann surface, be a positive smooth function
on . It is well known the functional achieves its minimum under
Ding-Jost-Li-Wang condition. This result was generalized to nonnegative by
Yang and the author. Later, Sun and Zhu (arXiv:2012.12840) showed
Ding-Jost-Li-Wang condition is also sufficient for achieves its minimum
when changes sign, which was reproved later by Wang and Yang (J. Funct.
Anal. 282: Paper No. 109449, 2022) and Li and Xu (Calc. Var. 61: Paper No. 143,
2022) respectively using flow approach. The aim of this note is to give a new
proof of Sun and Zhu's result. Our proof is based on the variational method and
the maximum principle.Comment: 13 pages. To appear on Proc. AM
Pyrrolylaldiminato complexes of Zn, Mg and Al
No full textThe reaction of 2-(2,6-iPr(2)C(6)H(3)N = CH)-5-R-C4H2NH (R = H, (LH)-H-1; R = tBu, (LH)-H-2) with one equivalent of ZnMe2 or MgnBu(2) in toluene or n-hexane afforded the bis(pyrrolylaldiminato) complexes ZnL21 (1), ZnL22 (2) and MgL22 (3). Crystalline 2 2 MgL21.THF (4THF) was formed by treatment of LiL1 with MeMgCl in THF followed by recrystallization from n-hexane. (LAlMe2)-Al-1 (6) and (LAlMe2)-Al-2 (7) were readily prepared by refluxing (LH)-H-1 and (LH)-H-2 with AlMe3 in toluene or n-hexane for several hours, However, the reaction of LiL1 with AlCl3 in a 1:1 molar ratio provided (L2AlCl)-Al-1 (8), while the reaction of KL2 with AlCl3 afforded (LAlCl2)-Al-2 (9). Compounds 2, 3, 5, and 8 were characterized by a single-crystal X-ray structural analysis. Compounds 2, 3, and 5 all have a tetrahedral geometry around the metal atom, while the five-coordinate aluminum in 8 has a trigonal bipyramidal geometry
Pyrrolylaldiminato complexes of Zn, Mg and Al
No full textThe reaction of 2-(2,6-iPr(2)C(6)H(3)N = CH)-5-R-C4H2NH (R = H, (LH)-H-1; R = tBu, (LH)-H-2) with one equivalent of ZnMe2 or MgnBu(2) in toluene or n-hexane afforded the bis(pyrrolylaldiminato) complexes ZnL21 (1), ZnL22 (2) and MgL22 (3). Crystalline 2 2 MgL21.THF (4THF) was formed by treatment of LiL1 with MeMgCl in THF followed by recrystallization from n-hexane. (LAlMe2)-Al-1 (6) and (LAlMe2)-Al-2 (7) were readily prepared by refluxing (LH)-H-1 and (LH)-H-2 with AlMe3 in toluene or n-hexane for several hours, However, the reaction of LiL1 with AlCl3 in a 1:1 molar ratio provided (L2AlCl)-Al-1 (8), while the reaction of KL2 with AlCl3 afforded (LAlCl2)-Al-2 (9). Compounds 2, 3, 5, and 8 were characterized by a single-crystal X-ray structural analysis. Compounds 2, 3, and 5 all have a tetrahedral geometry around the metal atom, while the five-coordinate aluminum in 8 has a trigonal bipyramidal geometry
Ding projective and Ding injective modules over trivial ring extensions
No full textsummary:Let be a trivial extension of a ring by an --bimodule such that , , and have finite flat dimensions. We prove that is a Ding projective left -module if and only if the sequence is exact and is a Ding projective left -module. Analogously, we explicitly describe Ding injective -modules. As applications, we characterize Ding projective and Ding injective modules over Morita context rings with zero bimodule homomorphisms
- …
