AMINO ACIDS
·
2020
·Vol. 52
·期 5
·831-839
·
IF 3.063
Zhao Dongxin,Lu Kui,Liu Guangbin,Zhu Hanjing,Ma Li,Qi Jianzhao,Yuan Libo
BRCA2 is an important tumor suppressor gene that plays a critical role in preserving the stability of cellular genetic information, participating in DNA repair by engaging in binding interactions with RAD51 proteins. However, the lack of structural data on BRCA2 and RAD51 makes the study of their interaction mechanism still a great challenge. We characterize the structure of the BRC8–RAD51 complex using ZDOCK protein docking software and identify the potential non-conserved active site of BRC8 via virtual alanine scanning, utilizing the obtained results to synthesize BRC8, its six analogous peptides (BRC8-1 to BRC8-6), and critical peptide fragment of RAD51 (RAD51(231–260)) by Fmoc solid-phase synthesis. The analogous peptides are found to exhibit a secondary structure significantly different from that of BRC8 by circular dichroism spectroscopy, which indicates that mutation sites determined by computer-aided simulation correspond to key amino acid residues substantially affecting polypeptide structure. On the other hand, the secondary structure of RAD51(231–260) was also considerably influenced by its interaction with BRC8 and analogs, e.g., the fraction of the α-helical structure in RAD51(231–260) increased to 23.6, 15.1, and 13.5% upon interaction with BRC8-1, BRC8-3, and BRC8-6, respectively. The results show that the properties of C-terminal amino acid residues significantly influence peptide–peptide interactions, in agreement with the results of virtual alanine scanning. Therefore, computer-aided simulation was confirmed to be a technique that is useful for narrowing down the range of sites responsible for interactions between peptides or proteins, and provides new inspirations for the design of peptides with strong interactions.
研究领域:
生物化学
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分子生物学
·
结构生物学
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DOI
PubMed
高影响因子
International Journal of Peptide Research and Therapeutics
·
2021
·Vol. 27
·期 2
·1343-1350
·
IF 1.931
Zhao Yi,Sun Guangming,Yuan Libo,Li Jinlei,Lu Kui
Breast cancer susceptibility gene 1 (BRCA1) is an important tumor suppressor gene in the human which associated with a variety of tumor suppressor genes to inhibit the growth of malignant tumors. Breast cancer is closely related to BRCA1 mutations in humans. Four BRCA1 (856-871) mutants were screened that can interact well with RAD51 (158-180) using computer to simulate mutations at Y 856, R 866 and Q 867. These mutants were synthesized by using Fmoc solid-phase synthesis, and purified by liquid chromatography. According to the results of fluorescence spectroscopy, R866W has the strongest binding ability for the above peptides and RAD51 (158-180). Based on the circular dichroism spectrum results, the sequence of the interaction ability of the above peptides on the secondary structure of RAD51 (158-180) is Y856P, Q867C > Y856P, R866W ≈ R866W > Y856P > BRCA1. All the spectral results show that R866W have the strongest interaction ability with RAD51(158-180).
研究领域:
分子生物学
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肿瘤学
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生物化学
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DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 7
·931-940
·
IF 1.42
Liu Rui-yuan,Zhang Tong,Yang Xiao-dong,Yan Yi-chen,Qu Jin-qing
A novel phenylacetylene derivative containing urea groups was synthesized and polymerized with a Rh catalyst to give the corresponding polymer, poly( 1 ) with moderate number-average molecular weights. The poly( 1 ) was soluble in toluene, CHCl 3 , CH 2 Cl 2 , THF, DMF, and DMSO, but insoluble in hexane, diethyl ether and MeOH. The specific rotation and circular dichroism (CD) spectroscopic studies revealed that poly( 1 ) took predominantly one-handed helical structures. The presence of intramolecular hydrogen bonding was confirmed by liquid-state IR spectroscopy. The helicity of poly( 1 ) could be tuned by temperature and anion. The helical conformation of the polymer was stable against Br- but susceptible to F − .
研究领域:
有机化学
·
高分子化学
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DOI
高影响因子
MEDICINAL CHEMISTRY RESEARCH
·
2016
·Vol. 26
·期 2
·405-413
·
IF 1.436
Wang Jie,Chan Calvin,Huang Feng-wen,Xie Jiang-feng,Xu Hong,Ho Ka-wai,Zheng Sheng-gang,Hu Zhang-li,Lu Jun,He Zhen-dan
The interaction of gastrodin with pepsin has been investigated by enzyme activity assay, fluorescence, UV–Visible, circular dichroism spectra, and molecular docking. The pepsin activity results suggest that gastrodin is an inhibitor of pepsin. The fluorescence experiments show that gastrodin can quench the fluorescence of pepsin via a static quenching process. The thermodynamic analysis suggests that hydrophobic interaction is the main force between pepsin and gastrodin. UV–Visible and circular dichroism spectra studies suggest that the binding of gastrodin leads to a loosening and unfolding of pepsin backbone with partial α-helix being transformed into β-sheet. All these experimental results have been validated by docking studies, which further show that besides hydrophobic interaction, hydrogen bond also help stabilize the gastrodin–pepsin complex. The results reveal the potential to develop the natural compound gastrodin for the treatment of diseases related to the excessive activity of pepsin.
研究领域:
生物化学
·
药物化学
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DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Shanshan Wu,Zheng-Zhi Yin,Datong Wu,Yongxin Tao,Yong Kong
π-Conjugated porphyrins have aroused particular attention for nanofabrication and biomimics; however, little attention has been paid to porphyrins-based chiral analysis owing to the achiral feature of porphyrins. Here, we demonstrated a chiral self-assembly of achiral porphyrin induced by l- and d-lysine (l- and d-Lys), and the resultant porphyrin self-assembly exhibited alterable morphologies depending on the inducer used (l- or d-Lys). The supramolecular chirality of the self-assembly was characterized by circular dichroism (CD) spectra, confirming successful transfer of molecular chirality from l- and d-Lys to the self-assembly. The enantioselective property of the chiral self-assembly was also investigated by using tryptophan (Trp) isomers as the model, and the results indicated that the developed chiral self-assembly showed significantly higher affinity toward l-Trp than d-Trp. Also in this work, the l-/d-Lys-induced chiral self-assembly of porphyrin and the supramolecular interaction between the self-assembly and l-/d-Trp were also studied by density functional theory (DFT).
研究领域:
化学
·
生物化学
·
材料科学
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DOI
PubMed
高影响因子
ACS Omega
·
2018
·
IF 0
Lingli Zhang,Chenxi Zhang,Wenjie Zhang,Zhe Cui,Peng Fu,Minying Liu,Xinchang Pang,Qingxiang Zhao
In this work, we have explored a simple and facile approach to prepare optically active helical polyamides. The hydroxyl groups of l-TA and d-TA were protected by O-alkoyl ester, and the resulting enantiomers, l-2,3-di-O-acetyl-tartaric acid (l-ATA) and d-2,3-di-O-acetyl-tartaric acid (d-ATA) crystals, were obtained. A pair of aliphatic homochiral polyamides of PA-l and PA-d are prepared using l-ATA, d-ATA, and achiral 1,11-undecanediamine as building blocks via interfacial polycondensation. PA-l and PA-d display negative and positive mirror circular dichroism (CD) spectra images in both solution and solid state. Moreover, the polyamides in solid state display different CD signals and stronger optical activity compared to those in ethanol and even the related chiral monomers in solid state, which was due to the helical conformation of the polyamides in solid state. Scanning electron microscopy results indicated that the aggregations of PA-l express left-handed helical sense, whereas those of PA-d express right-handed helix. In addition, the induced CD signals from the chiral conformation of the backbone become weaker when increasing the temperature from 0 to 60 °C in dilute solution. Either of the polyamides displays relatively stable CD images in solid state when elevating the temperature from 0 to 90 °C.
研究领域:
高分子化学
·
材料科学
·
物理化学
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DOI
PubMed
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2017
·
IF 2.536
Hongmei Zhang,Shixin Sun,Yanqing Wang,Jian Cao
The objective of this research was to study the interactions of sucralose with whey protein isolate (WPI) by using the three-dimensional fluorescence spectroscopy, circular dichroism spectroscopy and molecular modeling. The results showed that the peptide strands structure of WPI had been changed by sucralose . Sucralose binding induced the secondary structural changes and increased content of aperiodic structure of WPI. Sucralose decreased the thermal stability of WPI and acted as a structure destabilizer during the thermal unfolding process of protein. In addition, the existence of sucralose decreased the reversibility of the unfolding of WPI. Nonetheless, sucralose–WPI complex was less stable than protein alone. The molecular modeling result showed that van der Waals and hydrogen bonding interactions contribute to the complexation free binding energy. There are more than one possible binding sites of WPI with sucralose by surface binding mode.
研究领域:
食品科学
·
生物化学
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产品关联
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Mogos Girmatsion,Han Dong,Bereket Abraha,Abdu Mahmud,Madhubabu Kasimala,Henok Gebremedhin,Awet Adhanom,Gang Lu,Fangwei Yang,Yahui Guo
Ciprofloxacin (CIP) is one of the common drug pollutants whose residues are often detected in the environment. In the current work, CIP was studied in aqueous environment based on a natural fluorescing compound called phycocyanin (PC). Using, a Spectro fluorophotometer, fluorescence detection of CIP was performed, and absorbance properties were studied using a UV–Visible spectrophotometer. In addition, a circular dichroism (CD) spectrophotometer and molecular docking analysis were implemented for further investigation. As the fluorometric measurement results showed, the fluorescence intensity of PC dropped linearly upon the addition of increasing amounts of CIP ranging from 0 to 120 μmol/L of final concentrations, with the limit of detection reaching down to 95 nM. In addition, the fluorescent sensor was found to be more selective towards CIP when tested against other six antibiotics and six pesticides. In the case of analysis of the PC-CIP interaction using a CD spectrophotometer the α-helix content of PC decreased in the presence of CIP, which is an indication of conformational changes in the secondary structure of PC. Moreover, the molecular docking analysis of the PC-CIP interaction assisted in locating the three sites where CIP binds with CIP, which in turn provided additional instances of the interaction mechanism between PC and CIP.
研究领域:
环境科学
·
生物化学
·
药物分析
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DOI
高影响因子
JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
·
2017
·Vol. 54
·期 11
·3421-3432
·
IF 1.262
Lei Shicheng,Xu Donglan,Saeeduddin Muhammad,Riaz Asad,Zeng Xiaoxiong
In this study, theaflavins (TF1, TF2A, TF2B and TF3) were prepared from black tea and their interaction with bovine serum albumin (BSA) was explored by fluorescence and CD spectroscopy. The results showed that the structures of theaflavins exhibited significant effects on the binding/quenching process, and the binding affinity increased with the increase of molecular weight of theaflavins and the presence of galloyl moiety. The quenching effects showed a sequence as TF3 > TF2A > TF2B > TF1, demonstrating the important role of the galloyl moiety on the C-3 position of theaflavins. CD spectra indicated that TF3 in high concentration could change the skeleton structure of BSA and induce the unfolding of BSA secondary structure. The present results provide a new perspective for better understanding of the likely physiological fate of theaflavins and help to control the functional characteristics of food.
研究领域:
食品科学
·
生物化学
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DOI
PubMed
高影响因子
International Journal of Peptide Research and Therapeutics
·
2019
·Vol. 26
·期 1
·121-128
·
IF 1.219
Wang Mengwei,Lv Mingxiu,Lu Kui,Liu Guangbin,Mai Wenpeng,Yu Bo,Lou Yudan
Six breast cancer susceptibility gene 1 (BRCA1) peptide fragments were designed by removing N-terminal amino acid residues of BRCA1(846–871). Peptide fragments BRCA1(846–871), BRCA1(852–871), BRCA1(854–871), BRCA1(856–871), BRCA1(857–871) and BRCA1(861–871) were obtained by Fmoc solid-phase synthesis, purified by reversed-phase high-performance liquid chromatography and characterized by electrospray ionization mass spectrometry. The interaction between BRCA1 fragment peptides and RAD51(181–200) target peptides were investigated using circular dichroism (CD) spectroscopy, fluorescence spectroscopy, and microscale thermophoresis (MST). The results of CD spectroscopy showed that the secondary structures of RAD51(181–200) were altered after the addition of BRCA1 peptide fragments. The fluorescence results proved that all six BRCA1 peptide fragments BRCA1(846–871), BRCA1(852–871), BRCA1(854–871), BRCA1(856–871), BRCA1(857–871) and BRCA1(861–871) could bind to RAD51(181–200) independently, their quenching processes were static, and the binding constant of peptide fragments with RAD51(181–200) were 4.01 × 10 5 L mol −1 , 7.22 × 10 5 L mol −1 , 7.84 × 10 5 L mol −1 , 1.1 × 10 4 L mol −1 , 6.19 × 10 3 L mol −1 , 6.18 × 10 3 L mol −1 . The results of MST displayed that BRCA1(854–871) could combine with RAD51(181–200), and the dissociation constant K d was 126.44 µM. Compared with other five peptide fragments, the interaction between BRCA1(854–871) and RAD51(181–200) was much stronger.
研究领域:
生物化学
·
分子生物学
·
癌症研究
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DOI
高影响因子
STARCH-STARKE
·
2015
·
IF 1.677
Xuan Liang,Shuyun Wu,Xianyue Ren,Daping Quan,Li-Ming Zhang,Yubing Deng,Liqun Yang
A series of hyperbranched glycogen derivatives conjugated with different contents of cationic 3-(dimethylamino)-1-propylamine residues, named DMAPA-Glyp derivatives, were synthesized at room temperature. Resonance light scattering (RLS) spectroscopy was used to investigate the complexation behavior and efficacy of the DMAPA-Glyp derivatives and plasmid DNA (pDNA). Results indicated that the DMAPA-Glyp derivatives and pDNA molecules began to aggregate and form complexes at a weight ratio of 2. Following further increases in the DMAPA-Glyp derivatives (w/w >2), pDNA was condensed to form compact complexes. RLS spectroscopy is thus a useful tool for studying the complexation behavior and efficacy of cationic polymers with nucleic acid molecules. Circular dichroism analysis further revealed that the conformation of pDNA transformed from B-form to C-form and A-form during the complexation process.
研究领域:
生物化学
·
分子生物学
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DOI
高影响因子
POLYMER JOURNAL
·
2023
·Vol. 55
·期 3
·203-211
·
IF 2.8
Shi Zhichun,Wen Jiaxiang,Zhao Yingnan,Wang Jianjun,Li Jun,Zhao Ming,Teraguchi Masahiro,Aoki Toshiki,Kaneko Takashi
A novel substituted phenylacetylene with a pendant betulin derivative group was designed and synthesized successfully, and the chemical structure of the monomer was confirmed by nuclear magnetic resonance spectroscopy (NMR, 1 H, 13 C), high-resolution mass spectrometry (HRMS) and Fourier transform infrared spectroscopy (FTIR). The obtained monomer was further polymerized in an achiral [Rh(nbd)Cl] 2 /triethylamine (TEA) catalytic system, and the resulting polymer exhibited a strong Cotton effect at the main-chain absorption regions in the circular dichroism (CD) spectra. This one-handed helical backbone was induced by the chiral source on the side chain and maintained by the rigid betulin derivative pendant flats. Furthermore, the rigid betulin derivatives also contributed to the porous morphology and perfect thermal stability of the polymer. This study will provide a new method for preparing porous chiral polymers as efficient separation materials to solve practical issues.
研究领域:
材料化学
·
有机合成
·
高分子科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）