Synthetic and Systems Biotechnology
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2024
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IF 4.4
Moli Sang,Qingyu Yang,Jiawei Guo,Peiyuan Feng,Wencheng Ma,Wei Zhang
A novel sub-class of S -adenosyl- l -methionine (SAM)-dependent methyltransferases catalyze atypical chemical transformations in the biosynthesis of anthracyclines. Exemplified by RdmB from Streptomyces purpurascens, it was found with 10-decarboxylative hydroxylation activity on anthracyclines. We herein investigated the catalytic activities of RdmB and discovered a previously unknown 4- O -methylation activity. The site-directed mutagenesis studies proved that the residue at position R307 and N260 are vital for the decarboxylative hydroxylation and 4- O -methylation, respectively, which define two distinct catalytic centers in RdmB. Furthermore, the multifunctionality of RdmB activity was found as cofactor-dependent and stepwise. Our findings expand the versatility and importance of methyltransferases and should aid studies to enrich the structural diversity and bioactivities of anthracyclines.
研究领域:
微生物学
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生物化学
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药物化学
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Yongli Zhang,Zhao Zhou,Jun Wu,Yiyang Shi,Xinxiao Sun,Jia Wang,Xiaolin Shen,Qipeng Yuan
Methylation reactions are involved in the synthesis of various natural molecules, but the limited supply of intracellular S-adenosylmethionine (SAM) poses a challenge for the large-scale microbial production of methylated compounds. In this study, we conducted a comprehensive analysis and optimization of the SAM cycle regeneration pathway, enhancing the methylation efficiency in three key steps of the pathway (SAM carbon skeleton cycle, 5-methyltetrahydrofolate cycle, and adenine-ATP cycle), and constructed an efficient endogenous methylation platform in E. coli . This platform significantly increased the intracellular level of the cofactor SAM and improved methylation efficiency. Using this platform, the production of methylated products, including ferulic acid, vanillyl alcohol, and melatonin, increased by 4.2-fold, 1.28-fold, and 44.6 %, respectively. Notably, the ferulic acid titer reached 7.24 g/L, marking the highest level reported to date. These findings demonstrate the broad applicability of this methylation platform, providing a generalizable and effective approach for the biosynthesis of a wide range of SAM-dependent products.
研究领域:
生物工程
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代谢工程
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合成生物学
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高影响因子
ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Ang Li,Jian Sun,Haoqiang Yan,Dayu Li,Wei Xu
In miniature ion trap mass spectrometry, achieving a balance between isolation resolution and efficiency is a formidable challenge. The presence of absorption curves causes target ions to inadvertently absorb energy from AC signal components near their resonant frequencies. To mitigate this issue, SAM–SFM waveforms introduce a parameter known as the decreasing factor. Unlike SWIFT waveforms, SAM–SFM’s spectral profile intentionally departs from a rectangular window, adopting an arch-shaped excitation window to minimize the impact on target ions and improve ion isolation efficiency. SAM–SFM waveforms have the advantage of low computational complexity, enabling real-time computation using an embedded FPGA technology. Regardless of any parameter changes, the FPGA can consistently guarantee waveform output within 1 μs. This not only enhances throughput but also eliminates the need for a PC in miniature mass spectrometry devices. The performance of SAM–SFM has been validated on an improved “Brick” miniature ion trap mass spectrometer. Comparative experiments with SWIFT waveforms confirm the lossless unit-mass isolation capabilities of SAM–SFM. This waveform has the capability to simultaneously isolate multiple target ions, even allowing for the lossless isolation of ions with lower abundance within isotopic clusters, albeit at the cost of requiring extended isolation durations.
研究领域:
分析化学
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质谱技术
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仪器科学与技术
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PubMed
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2018
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IF 3.235
Qing Zheng,Huibo Shao
We have explored the intermolecular interactions within a two-component self-assembled monolayer, a model system to develop our understanding of interfacial chemistry in molecular level. The redox signal of 11-ferrocenyl-1-undecanethiol (FcC11) reversibly responded to the formation of intermolecular H-bonding: The intermolecular H-bonding between the terminal carboxyl groups of MSA promoted the formation of MSA assemblies, which increased the influence of MSA on the neighboring molecules (FcC11). Meanwhile, the disordered FcC11 appeared within the locally ordered FcC11 patches, resulting in the presence of a new couple of redox peaks in the cyclic voltammograms. The surface coverage that corresponding to the H-bonding affected FcC11 increased exponentially from 0 to 3.49 × 10 −10 mol cm −2 as a function of the time of MSA assembly. The pK 1/2 value (the pH when half of the –COOH groups are ionized) that determined for the FcC11/MSA modified gold substrate was obviously higher than the alkanoic acids in aqueous solution. The results show that the intermolecular H-bonding between MSA molecules plays a key role in controlling the molecular assembly within the two-component self-assembled monolayer, which provides an approach for regulating the structural changes of the model membrane in molecular level.
研究领域:
表面化学
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电化学
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材料科学
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分子相互作用
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DOI
高影响因子
MEDICAL SCIENCE MONITOR
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2019
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IF 1.98
Guomin Li,Lirong Zeng,Haiyan Cheng,Jingxian Han,Xuezhu Zhang,Hui Xie
Background Alzheimer’s disease (AD) is an age-associated neurodegenerative disorder. This study aimed to investigate effects of acupuncture administration on cognitive function and associated mechanisms. Material/Methods Senescence-accelerated prone 8 (SAM-P8) mice were randomly divided into 3 groups: the SAM-P8 group (P8-CN), the SAM-P8 administrating with acupuncture (P8-Acup) group, and the SAM-P8 administrating without acupuncture (P8-Sham) group. Morris water maze test was conducted to evaluate cognitive functions (memory and learning ability). PDK1, nPKC, and Rac1 inhibitors were used to treat SAM-P8 mice. Transmission electron microscope analysis was used to examine nuclear damage hippocampal tissues. Hematoxylin and eosin (H&E) staining was employed to evaluate inflammation. Western blot was used to detect PI3K, PDK1, nPKC, and Rac 1 expression in hippocampal tissues. Results Acupuncture administration significantly reduced PI3K, PDK1, nPKC, and Rac 1 levels compared to P8-CN group ( P <0.05). Both acupuncture and enzyme inhibitors (NSC23766, Rottlerin, {"type":"entrez-protein","attrs":{"text":"OSU03012","term_id":"1188654652","term_text":"OSU03012"}} OSU03012 ) significantly improved cognitive functions, reduced inflammation, and alleviated nuclear damages of SAM-P8 mice compared to P8-CN group ( P <0.05). Acupuncture significantly enhanced effects of inhibitors on inflammation and nuclear damages compared to inhibitor treatment single ( P <0.05). Acupuncture significantly enhanced down-regulative effects of {"type":"entrez-protein","attrs":{"text":"OSU03012","term_id":"1188654652","term_text":"OSU03012"}} OSU03012 on PI3K and PDK1 levels, increased down-regulative effects of Rottlerin on nPKC and Rac 1 levels and enhanced effects of Rottlerin on Rac 1 compared to P8-CN group ( P <0.05). Conclusions Acupuncture administration improved cognitive functions and alleviated inflammatory response and nuclear damage of SAM-P8 mice, by downregulating PI3K/PDK1/nPKC/Rac 1 signaling pathway. This study could provide potential insight for treating cognitive dysfunction and aging of AD patients.
研究领域:
神经生物学
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老年医学
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中医药学
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PubMed
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-14
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IF 16.6
Xue Yanyan,Li Jun,Chen Dian,Zhao Xizhu,Hong Liang,Liu Yu
Growing RNAs fold differently as they are transcribed, which modulates their finally adopted structures. Riboswitches regulate gene expression by structural change, which are sensitive to co-transcriptionally structural biology. Here we develop a strategy to track the structural change of RNAs during transcription at single-nucleotide and single-molecule resolution and use it to monitor individual transcripts of the SAM-VI riboswitch (riboSAM) as transcription proceeds, observing co-existence of five states in riboSAM. We report a bifurcated helix in one newly identified state from NMR and single-molecule FRET (smFRET) results, and its presence directs the translation inhibition in our cellular translation experiments. A model is proposed to illustrate the distinct switch patterns and gene-regulatory outcome of riboSAM when SAM is present or absent. Our strategy enables the precise mapping of RNAs’ conformational landscape during transcription, and may combine with detection methods other than smFRET for structural studies of RNAs in general.
研究领域:
分子生物学
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结构生物学
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生物物理学
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基因调控
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高影响因子
APPLIED SURFACE SCIENCE
·
2025
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IF 6.9
Jingqi Wu,Rui Zhu,Haidong Yuan,Xiaoya Hou,Jie Zhang
Solution-processed thiol-based self-assembled monolayers (SAMs) are widely used to align electrode-semiconductor energy levels in flexible organic field-effect transistors (FOFETs), yet how SAM molecules simultaneously influence both electrode and dielectric interfaces in bottom-gate bottom-contact (BGBC) FOFETs remain underexplored. We employed two fluorinated thiols, aromatic and alkyl, to probe how their molecular backbones influence the electrode work function and semiconductor crystallization. Combining experimental characterization with density functional theory (DFT) calculations, the study revealed that aromatic 4-trifluoromethyl-2,3,5,6-tetrafluorothiophenol (TTFP) not only increased the work function (WF) from 3.72 eV to 3.96 eV, but also, through its vertically-standing aromatic rings on the dielectric, facilitated π-π interactions that guide TIPS-pentacene into edge-on orientation, yielding large, highly ordered crystals. This enabled efficient 3 V FOFET operation, with a mobility ( μ ) of 0.32 cm 2 V −1 s −1 (60 % over unmodified), an on/off current ratio ( I on / I off ) of ∼ 10 5 , and a reduced threshold voltage ( V th ) of 0.82 V. Conversely, although the alkyl 1H,1H,2H,2H-perfluorodecanethiol (PFDT) also raised the electrode WF to 3.90 eV, its horizontally-lying chains on the dielectric disrupted π-π stacking, resulting in small, randomly oriented grains and degraded performance. This study reveals the distinct interfacial impacts of aromatic and alkyl thiols in BGBC-FOFETs, guiding rational material selection and FOFETs performance optimization.
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高影响因子
Biomolecules
·
2025
·Vol. 15
·期 6
·841
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IF 4.8
Yanyan Xue,Yi Sun,Yichun Xia,Xiuming Liu,Hua Dai
Riboswitches regulate gene expression through intricate dynamic conformational transitions, with divalent cation Mg2+and their ligands playing pivotal roles in this process. The dynamic structural mechanism by which the S-adenosyl-L-methionine (SAM) responsive SAM-VI riboswitch (riboSAM) regulates the downstream SAM synthase gene translation remains unclear. In this study, we employed position-selective labeling of RNA (PLOR) to incorporate Cy3-Cy5 into designated positions of riboSAM, applying single-molecule Förster resonance energy transfer (smFRET) method to track its conformational switches in response to Mg2+and SAM. smFRET analysis revealed that in the absence of Mg2+and ligand, riboSAM predominantly adopted a translation-activatingapoconformation. Physiological concentrations of Mg2+induced riboSAM to fold into dynamictransit-pandholo-pstates, creating a transient and structurally pliable binding pocket for ligand binding. SAM binding locks the dynamictransit-pandholo-pstates into their final stabletransitandholoconformations through conformational selection, turning off downstream cis-gene expression and completing feedback regulation of cellular SAM concentration. The observed synergistic regulatory effect of Mg2+ions and ligand on riboSAM’s conformational dynamics at single-molecule resolution provides new mechanistic insights into gene regulation by diverse riboswitch classes.
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高影响因子
LANGMUIR
·
2022
·
IF 4.331
Hira Khalid,Esther Martine Opodi,Xianneng Song,Ziyan Wang,Baili Li,Lixian Tian,Xi Yu,Wenping Hu
The organization of the self-assembled monolayer (SAM) determines its electronic structure and so governs the charge transport process and device performance when adopted into a molecular device. We report a systematic study on the supramolecular structure and rectification performance of the ferrocene (11-ferrocenyl-1-undecanethiol, FUT) based SAM modulated by mixed SAM with inert 1-undecanethiol (C11SH) as diluent. We compared mixed SAMs by two different post assembly strategies, i.e., post assembly of C11SH on FUT SAM and post assembly of FUT on C11SH SAM. The organization and structure of FUT in the mixed SAM were extensively studied by cyclic voltammetry (CV) using the Laviron model. Rectification properties of the mixed SAM obtained using eutectic indium gallium (EGaIn) as the top electrode revealed that the magnitude and stability of the rectification ratio (RR) strongly correlated to not only the amount but also the phase structure and orientation of the FUT in the monolayer, resulting in a tunable RR and increased stability. The mixed monolayer achieved an increased performance relative to pure FUT by post assembling FUT on C11SH SAM, which formed an optimally dense and well-packed monolayer with the FUT head resting on the top of the alkane SAM.
研究领域:
材料科学
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电子工程
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化学
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高影响因子
Journal of Physical Chemistry Letters
·
2026
·
IF 4.5
Jiaxing Zhu,Qi Xiao,Renqiang Yang,Jiajun Luo,Jiang Tang
Tin-based perovskite light-emitting diodes (PeLEDs) have emerged as promising candidates for environmentally benign optoelectronic applications. However, their practical performance remains limited by severe interfacial defect states, particularly at the buried interface. In this work, we introduce a self-assembled monolayer (SAM) molecule [4-(3,6-dibromo-9H-carbazol-9-yl)butyl]phosphonic acid (Br-4P), combining NiOx to effectively mitigate interfacial defects for PEA2SnI4-based (PEA = phenethylammonium) pure-red PeLEDs. This SAM is meticulously designed with tailored dimensions to achieve interfacial structural synergy with PEA2SnI4, serving as a bridging component between NiOx and the perovskite. The insertion of Br-4P promotes superior crystallinity and more uniform crystal orientation, enables the passivation of undercoordinated Sn2+ species, and the phosphate group of Br-4P functions to anchor onto NiOx. As a result, the optimized PeLEDs achieved a peak external quantum efficiency of 6.19% at 623 nm with a narrow full width at half-maximum of 27 nm and a luminance of 226 cd·m–2. This work highlights the critical role of interface engineering in unlocking the potential of Sn-based perovskite emitters for high-efficiency, nontoxic light-emitting applications.
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高影响因子
TOXICOLOGY
·
2026
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IF 5.2
Huajie Yang,Haoyang Yuan,Yumeng Tai,Xi Chen,Xueli Yang,Chengzhi Chen,Liangpo Liu,Qiang Zhang,Naijun Tang
Arsenic is a widespread environmental pollutant associated with an increased risk of diabetes. However, the mechanisms by which N 6 -methyladenosine (m 6 A) RNA modification regulates insulin secretion following arsenic exposure remain largely unclear. In this study, MIN6 cells were exposed to 0–10 μmol·L⁻¹ sodium arsenite (NaAsO 2 ) for 36 h. Arsenic exposure reduced cellular metabolic activity and impaired glucose-stimulated insulin secretion (GSIS). Because S-adenosylmethionine (SAM) serves as a methyl donor for both arsenic methylation and m 6 A modification, we hypothesized that arsenic-induced SAM depletion may impair m 6 A methyltransferase activity, thereby disrupting m 6 A homeostasis and altering the expression of genes involved in insulin synthesis and secretion. Arsenic exposure significantly decreased intracellular SAM levels, global m 6 A abundance, and m 6 A methyltransferase activity. In addition, the mRNA expression of Mafa , Pdx1 , Foxa2 , and Glut2 was significantly reduced following arsenic exposure. SAM supplementation partially restored GSIS, global m 6 A abundance, total m 6 A methyltransferase activity in nuclear extracts, and attenuated the reduction in GLUT2 protein abundance. Moreover, arsenic exposure reduced m 6 A enrichment on Mafa and Pdx1 transcripts, whereas SAM supplementation attenuated these changes. Collectively, these findings suggest that arsenic exposure impairs insulin secretion in MIN6 cells, potentially through SAM depletion, disruption of m 6 A homeostasis, and altered m 6 A regulation of the MAFA–PDX1 regulatory network.
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高影响因子
Nanomaterials
·
2025
·Vol. 15
·期 24
·1886
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IF 4.3
Xiukun Zhong,Guohong Liang,Lingbei Meng,Wei Xi,Lin Gu,Nana Tian,Yong Zhai,Yutong He,Yuqiong Huang,Fengmin Jin,Hong Gao
This study addresses the challenges associated with transmission electron microscopy (TEM) image analysis of supported nanoparticles, including low signal-to-noise ratio, poor contrast, and interference from complex substrate backgrounds. This study proposes an automated segmentation and particle size analysis method based on a large-scale deep learning model, namely segment anything model (SAM). Using Ru/TiO2and related materials as representative systems, the pretrained SAM is employed for zero-shot segmentation of nanoparticles, which is further integrated with a custom image processing pipeline, including optical character recognition (OCR) module, morphological optimization, and connected component analysis to achieve high-precision particle size quantification. Experimental results demonstrate that the method retains robust performance under challenging imaging conditions, with a size estimation error between 3% and 5% and a per-image processing time under 1 min, significantly outperforming traditional manual annotation and threshold-based segmentation approaches. This framework provides an efficient and reliable analytical tool for morphological characterization and structure–performance correlation studies in supported nanocatalysts.
研究领域:
纳米材料
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催化化学
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电子显微学
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图像分析
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深度学习
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PubMed
高影响因子
危险品化学品经营许可证（带存储）