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1.
Phys Chem Chem Phys ; 21(21): 10908-10913, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31080970

RESUMO

We estimate the time- and temperature-evolution of spin energy levels in a metallopeptide by combining molecular dynamics with crystal field analysis. Fluctuations of tens of cm-1 for spin energy levels at fs times gradually average out at longer times. We confirm that local vibrations are key in spin dynamics.


Assuntos
Metaloproteínas/química , Simulação de Dinâmica Molecular , Termodinâmica , Fenômenos Magnéticos , Fatores de Tempo , Vibração
2.
J Phys Chem Lett ; 9(16): 4522-4526, 2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30044106

RESUMO

The pursuit of novel functional building blocks for the emerging field of quantum computing is one of the most appealing topics in the context of quantum technologies. Herein we showcase the urgency of introducing peptides as versatile platforms for quantum computing. In particular, we focus on lanthanide-binding tags, originally developed for the study of protein structure. We use pulsed electronic paramagnetic resonance to demonstrate quantum coherent oscillations in both neodymium and gadolinium peptidic qubits. Calculations based on density functional theory followed by a ligand field analysis indicate the possibility of influencing the nature of the spin qubit states by means of controlled changes in the peptidic sequence. We conclude with an overview of the challenges and opportunities opened by this interdisciplinary field.


Assuntos
Metaloproteínas/química , Peptídeos/química , Teoria Quântica , Cátions/química , Espectroscopia de Ressonância de Spin Eletrônica , Elementos da Série dos Lantanídeos/química , Modelos Químicos
3.
Genome Biol ; 8(6): R119, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17584493

RESUMO

BACKGROUND: Specific histone modifications can perform several cellular functions, for example, as signals to recruit trans-acting factors and as modulators of chromatin structure. Acetylation of Lys14 of histone H3 is the main target of many histone acetyltransferases in vitro and may play a central role in the stability of the nucleosome. This study is focused on the genome-wide binding of Saccharomyces cerevisiae histone acetyltransferases that are specific for Lys14 of histone H3. RESULTS: We have used a variation of the genome-wide location analysis method, based on a macroarray platform, to identify binding sites of yeast histone acetyltransferase catalytic subunits and to correlate their positions with acetylation of Lys14 of histone H3. Our results revealed that the histone acetyltransferases Sas3p and Gcn5p are recruited to a pool of intensely transcribed genes and that there is considerable overlap between the two cohorts of Sas3p and Gcn5p bound gene pools. We also demonstrate a positive correlation between binding sites of both proteins and the acetylation state of Lys14 of histone H3. Finally, a positive correlation between the decrease of H3 Lys14 acetylation in a GCN5 deleted strain and the Gcn5p genome occupancy is shown. CONCLUSION: Our data support a model in which both Gcn5p and Sas3p act as general activators of an overlapping pool of intensely transcribed genes. Since both proteins preferentially acetylate Lys14 of histone H3, our data support the hypothesis that acetylation of this specific residue facilitates the action of the transcriptional apparatus.


Assuntos
Histona Acetiltransferases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Acetilação , Imunoprecipitação da Cromatina , Regulação Fúngica da Expressão Gênica , Histonas/metabolismo
4.
J Biol Chem ; 281(46): 35404-12, 2006 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-16921172

RESUMO

Set1 is the catalytic subunit and the central component of the evolutionarily conserved Set1 complex (Set1C) that methylates histone 3 lysine 4 (H3K4). Here we have determined protein/protein interactions within the complex and related the substructure to function. The loss of individual Set1C subunits differentially affects Set1 stability, complex integrity, global H3K4 methylation, and distribution of H3K4 methylation along active genes. The complex requires Set1, Swd1, and Swd3 for integrity, and Set1 amount is greatly reduced in the absence of the Swd1-Swd3 heterodimer. Bre2 and Sdc1 also form a heteromeric subunit, which requires the SET domain for interaction with the complex, and Sdc1 strongly interacts with itself. Inactivation of either Bre2 or Sdc1 has very similar effects. Neither is required for complex integrity, and their removal results in an increase of H3K4 mono- and dimethylation and a severe decrease of trimethylation at the 5' end of active coding regions but a decrease of H3K4 dimethylation at the 3' end of coding regions. Cells lacking Spp1 have a reduced amount of Set1 and retain a fraction of trimethylated H3K4, whereas cells lacking Shg1 show slightly elevated levels of both di- and trimethylation. Set1C associates with both serine 5- and serine 2-phosphorylated forms of polymerase II, indicating that the association persists to the 3' end of transcribed genes. Taken together, our results suggest that Set1C subunits stimulate Set1 catalytic activity all along active genes.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Regulação Fúngica da Expressão Gênica , Histona-Lisina N-Metiltransferase , Histonas/química , Metilação , Ligação Proteica , Subunidades Proteicas
5.
FEBS Lett ; 579(19): 4063-8, 2005 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-16023114

RESUMO

HAT-B is a yeast histone acetyltransferase composed of Hat1, Hat2 and Hif1 proteins. We demonstrate that a hat2 mutant or a hat1hat2 double mutant, but not a hat1 mutant, have an extended life-span. Transcriptome analysis shows that the single hat mutants are not very different from wild type. However, the comparison of the hat1 and hat2 transcriptomes shows that they are different. The hat1hat2 double mutant shows a transcriptional phenotype similar to that of the hat1 mutant but strongly enhanced. These results indicate that Hat2p could have additional functions in the cell to those of Hat1p.


Assuntos
Acetiltransferases/genética , Deleção de Genes , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Transcrição Genética , Histona Acetiltransferases , Imunoprecipitação , Fenótipo , Sirtuínas/metabolismo , Telômero
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