JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2015
·Vol. 53
·期 21
·2469-2480
·
IF 3.113
Yong Deng,Xi Wang,Qiulin Yuan,Mengxiang Zhu,Ying Ling,Haoyu Tang
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamic acid-based N -carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I − counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures ( T pt s) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 2469–2480
研究领域:
高分子化学
·
生物材料
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DOI
高影响因子
Food Biophysics
·
2019
·Vol. 14
·期 2
·142-153
·
IF 2.411
Jiao Wenjuan,Li Lin,Fan Penghui,Zhao Di,Li Bing,Rong Hui,Zhang Xia
The effect of xanthan gum on the freeze-thaw stability of wheat gluten was evaluated during a 60-day storage period at −18 °C with thawing every 5 days for 4 h at 25 °C. The physicochemical and rheological properties of wheat gluten-xanthan gum mixtures with multiple scales were analyzed. In the control samples (wheat gluten without xanthan gum), the molecular weight by size-exclusion chromatography-multiple angle laser light scattering (SEC-MALLs), content of free SH groups measured by UV/VIS spectrophotometry, and the hole sizes in the wheat gluten network structure shown by SEM increased as the freeze-thaw storage time increased, while the surface hydrophobicity index (H 0 ) decreased. For the wheat gluten-xanthan gum mixtures, more disulfide bonds were preserved and numerous small pores in the wheat gluten structure were observed. Meanwhile, the sample with 0.225% xanthan gum (w/w) had the lowest content of free SH groups. The wheat gluten-xanthan gum mixtures had more α-helixes than the control samples with the same freeze-thaw storage time. Rheological analysis showed that the wheat gluten-xanthan gum mixtures had higher elasticity and viscosity than the control samples. Overall, the addition of xanthan gum improved the freeze-thaw stability of the wheat gluten network.
研究领域:
食品科学
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生物化学
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高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 102
·期 18
·7891-7900
·
IF 3.34
Pei Xiaolin,Wang Jiapao,Wu Yifeng,Zhen Xiaoting,Tang Manman,Wang Qiuyan,Wang Anming
Nitrile hydratase (NHase) has attracted considerable attention since it can efficiently catalyze the hydration of nitriles to valuable amides. However, the poor stability of NHase is one of the main drawbacks in the industrial application. In this study, we compared the structural difference between Fe-type and Co-type NHase and found that an extra α helix existed at the β-subunit surface of Co-type NHase (defined as the β-6th helix). Then, the effects of the β-6th helix were investigated on the thermal stability and the catalytic kinetics of a Co-type NHase from Aurantimonas manganoxydans ATCC BAA-1229 (NHase1229). When the β-6th helix was deleted or disrupted, the thermal stability of NHase1229 was reduced to 17.6 and 12.9% of that of wild NHase1229, respectively. Thus, the β-6th helix is important for the thermal stability of Co-type NHase. Based on the structural characteristics of Co-type NHase, the β-6th helix may be interacted with another helix at the α-subunit (defined as the α-2nd helix) by hydrophobic network just as a “magnetic suction buckle” on the enzyme surface to stabilize the binding of α- and β-subunits. The β-6th helix is located at the mouth of the substrate and product tunnel, so it plays crucial roles in catalytic process. Furthermore, the β-6th helix in NHase1229 was swapped with a thermophilic NHase fragment from Pseudonocardia thermophila JCM3095 (NHase1229-Swap). The thermal stability of NHase1229-Swap was significantly improved, and the half-life was approximately 2.4-fold at 40 °C than that of the wild NHase1229. The knowledge is useful for improving the stability of NHases by restriction fragment swapping.
研究领域:
生物化学
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酶工程
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PubMed
高影响因子
RSC Advances
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2015
·Vol. 5
·期 51
·40772-40778
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IF 3.84
Yan Wu,Xi Wang,Ying Ling,Haoyu Tang
Water-soluble polypeptides bearing various pyridinium groups (i.e., pyridinium, 2-methylpyridinium, 3-methylpyridinium, 4-methylpyridinium) and Cl− counter-anions have been prepared by nuleophilic substitutions between poly(γ-3-chloropropyl-L-glutamate) (PCPLG) or poly(γ-6-chlorohexyl-L-glutamate) (PCHLG) and pyridine or y-methyl pyridine (y = 2, 3, and 4). Polypeptides bearing pyridinium groups and BF4− counter-anions were prepared by ion-exchange reactions from the polypeptide–pyridinium conjugates with Cl− counter-anions. CD analysis revealed that water-soluble polypeptides adopted α-helical conformation in solutions with a fractional helicity in the range of 24.7–41.4%. Variable-temperature UV-vis spectroscopy revealed that polypeptides bearing 3-methylpyridinium and BF4− counter-anions (i.e., P11 and P15) showed upper critical solution temperature (UCST)-type transitions in aqueous solutions. The UCST-type phase transition temperatures increased as increasing the hydrophobicity of the spacer groups, the polymer concentrations, and the concentrations of NaBF4.
研究领域:
生物化学
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高分子化学
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材料科学
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高影响因子
JOURNAL OF BIOTECHNOLOGY
·
2017
·
IF 2.599
Xiaolin Pei,Zhengfei Yang,Anming Wang,Lirong Yang,Jianping Wu
Nitrile hydratase (NHase) has attracted considerable attention to synthesize valuable amides. Here, the gene cluster of Co-type NHase from Aurantimonas manganoxydans ATCC BAA-1229 (NHase1229) was identified through Edman degradation and recombinant expression, including α-subunit, β-subunit, and activator. The activator gene contained 408 bases, which was essential for the biosynthesis of NHase1229 in Escherichia coli . The activator gene can be substituted by Co-type activator from Pseudonocardia thermophila JCM3095 and Pseudomonas putida 5B to assist in the functional expression of NHase1229, not by that of Fe-type NHase from Pseudomonas putida F1. Multi-sequence alignment showed that the activator contained conserved amino acid residues (Trp34, Trp53, Phe 85, Gln35, Glu39, and Glu90), but these residues had no significant effect on activator function. Histidine residues (His112, His120, and His134) at the C-terminus only partially participated in the activator function. Furthermore, the successive α-helices in domain TIGR03889 were identified to be critical for the activator function. The integration efficiency of cobalt into the active site was decreased with the interruption of α-helices. Therefore, Co-type and Fe-type activators have specific functions for the integration of different metal ions, and four conserved α-helices in Co-type activator affect the integration of cobalt. These knowledge is useful for understanding the biosynthesis of Co-type NHase.
研究领域:
微生物学
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生物化学
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PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2015
·Vol. 33
·期 8
·1150-1161
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IF 1.835
Yuan Qiu-lin,Liu Wen-jun,Deng Yong,Ling Ying,Tang Hao-yu
A series of polypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol (OEG) tails (PPLG
n
- g -BPOEG
m
, n = 26 and 63, m = 2, 3, and 7) has been synthesized via a 1,3-dipolar cycloaddition with quantitative grafting density. FTIR results revealed that the polypeptides adopted highly stable α -helix in the temperature range of 25–200 °C. DSC, POM and WAXS analysis revealed that PPLG
n
- g -BPOEG
m
( m ≤ 3) samples with short OEG tail length showed two main phase transitions including crystal to liquid crystalline (smectic C, SmC) phase transition and the melting transition of crystalline E-phase, while PPLG
n
- g -BPOEG 7 with longer OEG tail length ( m = 7) exhibited the melting transitions without the formation of liquid crystalline phase.
研究领域:
材料科学
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生物化学
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DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Jiahui Zhang,Dongxin Zhao,Kui Lu,Libo Yuan,Heng Du
Based on the typical similar repeat units (abcdefg)n of α-helical structure, the peptide H was designed to self-assemble into an organohydrogel in response to pH. Depending on the different pH, the proportions of secondary structure, microstructure, and mechanical properties of the gel were investigated. Circular dichroism (CD) and Fourier transform infrared (FT-IR) showed that the proportion of α-helical structure gradually increased to become dominant with the increase of pH. Combining transmission electron microscopy (TEM) and atomic force microscopy (AFM), it was found that the increase of the ordered α-helix structure promoted fiber formation. The further increase in pH changed the intermolecular forces, resulting in an increase in the α-helix content and the enhancement of helix–helix interaction, causing the gel fibers to converge into thicker and more dense ones. The temperature test showed the stable rheological properties of the organohydrogel between 20–60 °C. Drug release and cytotoxicity showed that the DOX-loaded organohydrogel could have a better release in an acidic environment, indicating its potential application as a drug local delivery carrier.
研究领域:
生物化学
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材料科学
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药学
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PubMed
高影响因子
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2025
·
IF 5.9
Wanyang Xiao,Ruize Sun,Jietao Lou,Yanyan Xu,Xiaokun Li,Kaiyun Xin,Weijie Lu,Chenhui Sun,Tianbao Chen,Yitian Gao,Di Wu
The increasing prevalence of antibiotic-resistant Gram-negative bacteria necessitates the development of novel antimicrobial agents with targeted specificity. In this study, we designed and optimized derivatives of the antimicrobial peptide AA16, which truncated from CD14 protein α-helical region, to selectively target Gram-negative bacteria by enhancing lipopolysaccharide (LPS)-enriched interactions, thereby achieving antibacterial spectrum conversion. Starting from the parent peptide AA16 (Ac-AARIPSRILFGALRVL-Amide), we performed strategic amino acid substitutions based on structure–activity relationship analysis. This led to the identification of AA16-10R, a derivative with a specific substitution at position 10, which demonstrated significantly enhanced antibacterial activity against Gram-negative strains such as Escherichia coli and Pseudomonas aeruginosa , while maintaining low hemolytic activity. Mechanistic studies revealed that AA16-10R exhibited a strong binding affinity to LPS ( K d = 0.15 μM), and its interaction with LPS induced the formation of an α-helical structure. This conformational change facilitated its accumulation on the bacterial outer membrane and disrupted membrane integrity. Our innovative approach of exploiting LPS-enriched interactions successfully converted the antimicrobial spectrum of AA16 derivatives from broad-spectrum to Gram-negative-specific. This study highlights a novel strategy for the rational design of antimicrobial peptides based on specific protein–protein interactions, offering a promising avenue for targeted antimicrobial therapy against Gram-negative pathogens.
研究领域:
微生物学
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药物化学
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分子生物学
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Tongchao Su,Youtong Zhang,Wenkai Du,Jie Zeng,Haiyan Gao
The trehalose (TL) was modified with sodium alginate, starch, and the effects of modified trehalose particle on the gluten protein and steamed bread properties were investigated. The results showed that for dough frozen after 30 d, the addition of 0.8 % modified TL significantly increased water-holding capacity by 12.12 %, improved the freezing rate, and the change of binding water could be better controlled. Besides, the α-helix content and random coil content of gluten protein was increased and decreased after adding modified TL, respectively, improving the ordered structure of wheat gluten protein and maintaining its aggregation characteristics and structural stability to some extent. Meanwhile, the brightness, water-holding capacity and specific volume of steamed bread was increased after adding 0.8 % modified TL, which improved and maintained the normal texture and internal structure of steamed bread. The results can provide a basis for the application of trehalose in flour products.
研究领域:
食品科学
·
分子生物学
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DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2020
·
IF 4.006
Zongyun Yang,Jian Sun,Zhen Li,Yue Qi,Peng Wang,Xinglian Xu
An unresolved problem in the field of food protein is the poor dispersibility of pale, soft, exudative (PSE)-like meat protein. This study aimed to verify the structural and functional robustness of myosin. Two different models, namely, PSE-induced whole meat model and pH shifting plus temperature holding of protein solution model, were developed. A novel combination of pH shifting (from 5.6 to 7.0) and low speed shearing (400 rpm) treatment decreased myosin turbidity by 9.6% and 36.5%, respectively. After readjusting the pH to 7.0, z-average size decreased from 289.0 nm to 1563.6 nm–274.0 nm and 333.3 nm, respectively. The experimental groups exhibited excellent solubility like the normal group. Scanning electron microscopy revealed that large myosin clusters and aggregates decreased. The improvement in PSE myosin stability increased the absolute ζ-potential value from −13.1 mV to −15.5 mV under treatment. Raman analysis revealed that the increase in protein function was not only because of surface charge states induced by pH shifting but also because of conformation recovery as evidenced by the increase in α-helix content. Results indicated that pH shifting and proper low shearing could fulfill the robustness of myosin function by recovering conformation and improving solubility.
研究领域:
食品科学
·
蛋白质化学
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DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2014
·
IF 1.599
Yugang Huang,Weiang Luo,Guodong Ye
A new polypeptide-based copolymer brush composed of poly (γ-propargyl- L -glutamate)- block -poly (propylene oxide)- block -poly (γ-propargyl- L -glutamate) backbone (PPLG- b -PPO- b -PPLG) and oligo (ethylene glycol) (PEG) side-chain was synthesized by combination of N -carboxyanhydride ring-opening polymerization and click chemistry. Nearly 100% grafting efficiency was achieved by copper-catalyzed azide-alkyne Huisgen 1,3-dipolar cycloaddition (CuAAc) reaction. The α -helical conformation adopted by the grafted polypeptide blocks in water was relatively stable and showed a reversible change in a heating–cooling circle from 5 to 70 °C. It displayed weak stability against elevated temperature but still reversible changes in the presence of 0.47 M NaCl. The brushes were amphiphilic and could self-assemble into thermo-sensitive micelles in water. Big micelles could break into small micelles upon heating due to the improved solubility.
研究领域:
高分子化学
·
生物材料科学
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DOI
高影响因子
MACROMOLECULES
·
2016
·
IF 5.554
Mengxiang Zhu,Yan Wu,Chenglong Ge,Ying Ling,Haoyu Tang
Water-soluble random copolypeptides bearing pyridinium tetrafluoroborate (PyBF4) and oligo-ethylene glycol (OEG) pendants (PPLG-PyBF4-r-OEG) showed SO2-induced solution phase transition. They were prepared by sequential postpolymerizations including nucleophilic substitution of poly(γ-3-chloropropyl-l-glutamate) with sodium azide to partially convert chloro groups into azido groups, copper-mediated [2 + 3] alkyne–azide 1,3-dipolar cycloaddition to conjugate OEG pendants, another nucleophilic substitution to conjugate pyridinium chloride, and ion-exchange reaction. FTIR and CD analysis revealed that PPLG-PyBF4-r-OEG samples with suitable molar content of PyBF4 (x ≤ 0.4) were water-soluble and adopted α-helical conformation in both the solid-state and aqueous solution. UV–vis spectroscopy and dynamic light scattering (DLS) results revealed that PPLG-PyBF4-r-OEG aqueous solution underwent a reversible solution phase transition by sequentially bubbling SO2 and N2. 1H NMR analysis suggested that SO2 interacted with triazole groups and induced the solution phase transition.
研究领域:
生物化学
·
高分子化学
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DOI
高影响因子
危险品化学品经营许可证（带存储）