scholarly journals Diverse nucleosome Site-Selectivity among histone deacetylase complexes

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Zhipeng A Wang ◽  
Christopher J Millard ◽  
Chia-Liang Lin ◽  
Jennifer E Gurnett ◽  
Mingxuan Wu ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
Protein Complexes ◽  
Histone H3 ◽  
Biological Functions ◽  
Sharp Reduction ◽  
Cellular Functions ◽  
Site Specific ◽  
Site Selectivity ◽  
A Site ◽  
Site Selective

Histone acetylation regulates chromatin structure and gene expression and is removed by histone deacetylases (HDACs). HDACs are commonly found in various protein complexes to confer distinct cellular functions, but how the multi-subunit complexes influence deacetylase activities and site-selectivities in chromatin is poorly understood. Previously we reported the results of studies on the HDAC1 containing CoREST complex and acetylated nucleosome substrates which revealed a notable preference for deacetylation of histone H3 acetyl-Lys9 vs. acetyl-Lys14 (Wu et al, 2018). Here we analyze the enzymatic properties of five class I HDAC complexes: CoREST, NuRD, Sin3B, MiDAC and SMRT with site-specific acetylated nucleosome substrates. Our results demonstrate that these HDAC complexes show a wide variety of deacetylase rates in a site-selective manner. A Gly13 in the histone H3 tail is responsible for a sharp reduction in deacetylase activity of the CoREST complex for H3K14ac. These studies provide a framework for connecting enzymatic and biological functions of specific HDAC complexes.

New Zinc-bis(Dialkylamides) Potentially Usable as Site-Selective Dopants For p-Type ZnSe.

1993 ◽  
Vol 334 ◽  
Author(s):  
William S. Rees ◽  
Oliver Just
Keyword(s):  
Vapor Pressure ◽  
Gas Phase ◽  
Elemental Analysis ◽  
Vapor Pressures ◽  
Effective Utilization ◽  
Site Selectivity ◽  
A Site ◽  
P Type ◽  
Site Selective ◽  
C Nmr

AbstractIn earlier work, the effective utilization of Zn {N\Si(CH3)3]2}2 as a site-selective dopant for the production of p-type ZnSe by OMVPE was demonstrated. Several new zinc-bis(dialkylamides) of the general form (R)(R′)NZnN(R″)(R‴) now have been prepared. They have been characterized by 1H- and 13C-NMR, GC/MS and elemental analysis. Vapor pressures and gas phase decompositior profiles have been examined. Correlations of vapor pressure and structure are discussed for this series of compounds. A mechanism for the site-selectivity observed in the incorporation of nitrogen is proposed.

Uteroplacental insufficiency induces site-specific changes in histone H3 covalent modifications and affects DNA-histone H3 positioning in day 0 IUGR rat liver

2004 ◽  
Vol 20 (1) ◽  
pp. 108-116 ◽  
Author(s):  
Qi Fu ◽  
Robert A. McKnight ◽  
Xing Yu ◽  
Laiyi Wang ◽  
Christopher W. Callaway ◽  
...  
Keyword(s):  
Histone H3 ◽  
Site Specific ◽  
Promoter Sequences ◽  
Histone Deacetylase 1 ◽  
Protein Levels ◽  
Ppar Γ ◽  
Covalent Modifications ◽  
A Site ◽  
H3 Acetylation ◽  
Carnitine Palmitoyl Transferase I

Uteroplacental insufficiency and subsequent intrauterine growth retardation (IUGR) increase the risk of adult onset insulin resistance and dyslipidemia in humans and rats. IUGR rats are further characterized by postnatal alterations in hepatic PPAR-γ coactivator (PGC-1) and carnitine-palmitoyl-transferase I (CPTI) expression, as well as overall hyperacetylation of histone H3. However, it is unknown whether the histone H3 hyperacetylation is site specific or relates to the changes in gene expression previously described in IUGR rats. We therefore hypothesized that uteroplacental insufficiency causes site-specific modifications in hepatic H3 acetylation and affects the association of acetylated histone H3 with PGC-1 and CPTI promoter sequences. Uteroplacental insufficiency was used to produce asymmetrical IUGR rats. IUGR significantly increased acetylation of H3 lysine-9 (H3/K9), lysine-14 (H3/K14), and lysine-18 (H3/K18) at day 0 of life, and these changes occurred in association with decreased nuclear protein levels of histone deacetylase 1 (HDAC1) and HDAC activity. Chromatin immunoprecipitation using acetyl-H3/K9 antibody and day 0 chromatin revealed that uteroplacental insufficiency affected the association between acetylated H3/K9 and the promoters of PGC-1 and CPTI, respectively, in IUGR liver. At day 21 of life, the neonatal pattern of H3 hyperacetylation persisted only in the IUGR males. We conclude that uteroplacental insufficiency increases H3 acetylation in a site-specific manner in IUGR liver and that these changes persist in male IUGR animals. The altered association of the PGC-1 and CPTI promoters with acetylated H3/K9 correlates with previous reports of IUGR altering the expression of these genes. We speculate that in utero alterations of chromatin structure contribute to fetal programming.

1,3-Dipolar cycloadditions with meso-tetraarylchlorins – site selectivity and mixed bisadducts

2017 ◽  
Vol 4 (4) ◽  
pp. 534-544 ◽  
Author(s):  
José Almeida ◽  
António Aguiar ◽  
Andreia Leite ◽  
André M. N. Silva ◽  
Luís Cunha-Silva ◽  
...  
Keyword(s):  
Azomethine Ylide ◽  
Dipolar Cycloadditions ◽  
Porphyrin Macrocycle ◽  
Selective Approach ◽  
Site Selectivity ◽  
Sequential Addition ◽  
A Site ◽  
Site Selective

Mixed bisadducts resulting from the sequential addition of a nitrone and an azomethine ylide to the porphyrin macrocycle were efficiently obtained, in a site selective approach.

scholarly journals A site-selective and stereospecific cascade Suzuki–Miyaura annulation of alkyl 1,2-bisboronic esters and 2,2′-dihalo 1,1′-biaryls

2021 ◽  
Vol 57 (32) ◽  
pp. 3909-3912
Author(s):  
Suzanne Willems ◽  
Georgios Toupalas ◽  
Julia C. Reisenbauer ◽  
Bill Morandi
Keyword(s):  
Cross Coupling ◽  
Site Selectivity ◽  
A Site ◽  
Site Selective

A cascade Suzuki–Miyaura cross-coupling between two non-symmetrical coupling partners gave rise to 9,10-dihydrophenanthrenes with full site-selectivity. The choice of base was critical to facilitate the challenging coupling of the secondary boronate group.

scholarly journals Site-selective protein conjugation at histidine

2019 ◽  
Vol 10 (2) ◽  
pp. 427-439 ◽  
Author(s):  
Karolina Peciak ◽  
Emmanuelle Laurine ◽  
Rita Tommasi ◽  
Ji-won Choi ◽  
Steve Brocchini
Keyword(s):  
Molecular Engineering ◽  
Protein Conjugation ◽  
Site Specific ◽  
A Site ◽  
Site Selective

Site-selective conjugation generally requires both (i) molecular engineering of the protein of interest to introduce a conjugation site at a defined location and (ii) a site-specific conjugation technology.

Chemical and Electrochemical Heteroepitaxial Growth of Chalcogenide Semiconductors from Solutions

1996 ◽  
Vol 451 ◽  
Author(s):  
D. Lincot ◽  
M. J. Furlong ◽  
M. Froment ◽  
R. Cortes ◽  
M. C. Bernard
Keyword(s):  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Basic Principles ◽  
Lattice Match ◽  
X Ray ◽  
Chalcogenide Semiconductors ◽  
Influence Of Temperature On ◽  
Deposition Processes ◽  
A Site ◽  
Site Selective

ABSTRACTChalcogenide semiconductors have been deposited epitaxially from aqueous solutions either chemically or electrochemically at growth rates of up to 0.7 μmhr−1. After recalling the basic principles of these deposition processes, results are presented concerning chemically deposited CdS on InP, GaP and CuInSe2 substrates, electrodeposited CdTe on InP, and CdSAnP heterostructures. Characterisation of these structures by RHEED, TEM, HRTEM, and glazing angle X ray diffraction allows to analyse the effects of substrate orientation, polarity, lattice match plus the influence of temperature on epitaxial growth. These results are discussed in terms of self organisation and a site selective growth mechanisms due to the free enegy of formation of each compound.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Systematic Engineering of a Protein Nanocage for High-Yield, Site-Specific Modification

2018 ◽  
Author(s):  
Daniel D. Brauer ◽  
Emily C. Hartman ◽  
Daniel L.V. Bader ◽  
Zoe N. Merz ◽  
Danielle Tullman-Ercek ◽  
...  
Keyword(s):  
Small Molecules ◽  
Protein Modification ◽  
Positive Charge ◽  
Specific Protein ◽  
High Yield ◽  
Site Specific ◽  
Protein Cage ◽  
Protein Carriers ◽  
Site Selective ◽  
Targeted Library

<div> <p>Site-specific protein modification is a widely-used strategy to attach drugs, imaging agents, or other useful small molecules to protein carriers. N-terminal modification is particularly useful as a high-yielding, site-selective modification strategy that can be compatible with a wide array of proteins. However, this modification strategy is incompatible with proteins with buried or sterically-hindered N termini, such as virus-like particles like the well-studied MS2 bacteriophage coat protein. To assess VLPs with improved compatibility with these techniques, we generated a targeted library based on the MS2-derived protein cage with N-terminal proline residues followed by three variable positions. We subjected the library to assembly, heat, and chemical selections, and we identified variants that were modified in high yield with no reduction in thermostability. Positive charge adjacent to the native N terminus is surprisingly beneficial for successful extension, and over 50% of the highest performing variants contained positive charge at this position. Taken together, these studies described nonintuitive design rules governing N-terminal extensions and identified successful extensions with high modification potential.</p> </div>

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

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