scholarly journals Structural insights into the molecular mechanism of H-NOX activation

2010 ◽  
Vol 19 (4) ◽  
pp. 881-887 ◽  
Author(s):  
Charles Olea ◽  
Mark A. Herzik ◽  
John Kuriyan ◽  
Michael A. Marletta
Keyword(s):  
Molecular Mechanism ◽  
Structural Insights

Structural Insights into the Molecular Mechanism of Vitamin D Receptor Activation by Lithocholic Acid Involving a New Mode of Ligand Recognition

2014 ◽  
Vol 57 (11) ◽  
pp. 4710-4719 ◽  
Author(s):  
Anna Y. Belorusova ◽  
Jérôme Eberhardt ◽  
Noëlle Potier ◽  
Roland H. Stote ◽  
Annick Dejaegere ◽  
...  
Keyword(s):  
Vitamin D ◽  
Molecular Mechanism ◽  
Vitamin D Receptor ◽  
Lithocholic Acid ◽  
Receptor Activation ◽  
Ligand Recognition ◽  
Structural Insights

scholarly journals Dynamic structural insights into the molecular mechanism of DNA unwinding by the bacteriophage T7 helicase

2020 ◽  
Vol 48 (6) ◽  
pp. 3156-3164 ◽  
Author(s):  
Jian-Bing Ma ◽  
Ze Chen ◽  
Chun-Hua Xu ◽  
Xing-Yuan Huang ◽  
Qi Jia ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Molecular Mechanism ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Bacteriophage T7 ◽  
Dna Unwinding ◽  
Coupling Mechanism ◽  
Mechanical Coupling ◽  
Dna Complex ◽  
Structural Insights

Abstract The hexametric T7 helicase (gp4) adopts a spiral lock-washer form and encircles a coil-like DNA (tracking) strand with two nucleotides bound to each subunit. However, the chemo-mechanical coupling mechanism in unwinding has yet to be elucidated. Here, we utilized nanotensioner-enhanced Förster resonance energy transfer with one nucleotide precision to investigate gp4-induced unwinding of DNA that contains an abasic lesion. We observed that the DNA unwinding activity of gp4 is hindered but not completely blocked by abasic lesions. Gp4 moves back and forth repeatedly when it encounters an abasic lesion, whereas it steps back only occasionally when it unwinds normal DNA. We further observed that gp4 translocates on the tracking strand in step sizes of one to four nucleotides. We propose that a hypothetical intermediate conformation of the gp4–DNA complex during DNA unwinding can help explain how gp4 molecules pass lesions, providing insights into the unwinding dynamics of gp4.

scholarly journals Structural insights into the molecular mechanism of the m6A writer complex

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Paweł Śledź ◽  
Martin Jinek
Keyword(s):  
Molecular Mechanism ◽  
Active Site ◽  
Evolutionary History ◽  
Rna Binding ◽  
Biological Processes ◽  
Catalytic Core ◽  
Genome Regulation ◽  
History Of ◽  
Structural Insights ◽  
Critical Aspects

Methylation of adenosines at the N6 position (m6A) is a dynamic and abundant epitranscriptomic mark that regulates critical aspects of eukaryotic RNA metabolism in numerous biological processes. The RNA methyltransferases METTL3 and METTL14 are components of a multisubunit m6A writer complex whose enzymatic activity is substantially higher than the activities of METTL3 or METTL14 alone. The molecular mechanism underpinning this synergistic effect is poorly understood. Here we report the crystal structure of the catalytic core of the human m6A writer complex comprising METTL3 and METTL14. The structure reveals the heterodimeric architecture of the complex and donor substrate binding by METTL3. Structure-guided mutagenesis indicates that METTL3 is the catalytic subunit of the complex, whereas METTL14 has a degenerate active site and plays non-catalytic roles in maintaining complex integrity and substrate RNA binding. These studies illuminate the molecular mechanism and evolutionary history of eukaryotic m6A modification in post-transcriptional genome regulation.

Structural insights into the molecular mechanism underlying Sirt5-catalyzed desuccinylation of histone peptides

2019 ◽  
Vol 476 (2) ◽  
pp. 211-223 ◽  
Author(s):  
Tianrong Hang ◽  
Wanbiao Chen ◽  
Minhao Wu ◽  
Li Zhan ◽  
Chengliang Wang ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Main Chain ◽  
Regulatory Mechanism ◽  
Biological Processes ◽  
Biological Functions ◽  
Damage Repair ◽  
Biochemical Assays ◽  
Functional Consequences ◽  
Enzyme Recognition ◽  
Structural Insights

Abstract Histone modification is a ubiquitous regulatory mechanism involved in a variety of biological processes, including gene expression, DNA damage repair, cell differentiation, and ontogenesis. Succinylation sites on histones have been identified and may have functional consequences. Here, we demonstrate that human sirtuin 5 (Sirt5) catalyzes the sequence-selective desuccinylation of numerous histone succinyl sites. Structural studies of Sirt5 in complex with four succinyl peptides indicate an essential role for the conserved main chain hydrogen bonds formed by the succinyl lysine (0), +1, and +3 sites for substrate-enzyme recognition. Furthermore, biochemical assays reveal that the proline residue at the +1 site of the histone succinylation substrate is unfavorable for Sirt5 interaction. Our findings illustrate the molecular mechanism underlying the sequence-selective desuccinylase activity of Sirt5 and provide insights for further studies of the biological functions associated with histone succinylation and Sirt5.

Additional evidence for AQP1 vesicle trafficking as a molecular mechanism for ductal bile secretion

2001 ◽  
Vol 120 (5) ◽  
pp. A91-A91
Author(s):  
P TIETZ ◽  
P SPLINTER ◽  
M MCNIVEN ◽  
R HUEBERT ◽  
N LARUSSO
Keyword(s):  
Molecular Mechanism ◽  
Vesicle Trafficking ◽  
Bile Secretion
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