International Journal of Biological Macromolecules最新文献

Salidroside is a phenylpropanoid glycoside with wide applications in the food, pharmaceutical, and cosmetic industries; however, the plant genus Rhodiola, the natural source of salidroside, has slow growth and limited distribution. In this study, we designed a novel six-enzyme biocatalytic cascade for the efficient production of salidroside, utilizing cost-effective bio-based L-Tyrosine as the starting material. A preliminary analysis revealed that the poor thermostability of the Bacillus licheniformis UDP-glycosyltransferase (EC 2.4.1.384) BlYjiC M6 is a bottleneck in the cascade. Therefore, a combined computational strategy was used to engineer it and finally obtained a mutant TSM6 (T304V/G307A/N309W/F123W/T344V/D271G) with a 134-fold longer half-life at 40 °C and a 13 °C higher T_m^app compared to M6. The integration of TSM6 into the cascade improved salidroside productivity significantly, while reducing residual intermediates. After further optimization, the whole-cell biocatalytic cascade achieved a high salidroside titer of 12.8 g·L^-1 in a 5 L bioreactor, giving a productivity of 0.53 g·L^-1·h^-1. This study provides a green and efficient biosynthetic process for salidroside production and highlights the potential of enzyme engineering to enhance the biocatalytic cascade.

With the global population expected to reach 10 billion by the 2050s, the demand for protein will surge, intensifying the need for high protein utilization efficiency. This study investigates the use of protease-enhanced Streptomyces sp. SCUT-3-3940 to degrade soybean meal (SBM) via solid-state fermentation (SSF). Optimized conditions resulted in anti-nutritional factors elimination and high soluble protein recovery (41.1 g/100 g), including bioactive oligopeptides (17.3 g/100 g) with antihypertensive and antioxidant properties. The degradation also produced free amino acids rich in essential amino acids, and other nutrient enhancing compounds. The fermented SBM (FSBM) exhibited superior digestibility, making it a valuable protein source. In a 60-day largemouth bass trial, replacing 10 % SBM with FSBM in feed significantly improved feed intake and weight gain. This method offers an efficient, eco-friendly, and cost-effective solution to address global protein shortages.

Hydrogels with antioxidant and antibacterial activities have received increasing attention in wound healing due to excessive reactive oxygen species (ROS) and bacterial infection are common issues associated with wounds. Herein, we constructed a series of hydrogels with C-phycocyanin (C-PC), quaternized chitosan (QCS) and silk fibroin protein (SF) as matrixes, which with tetrakis hydroxymethyl phosphonium sulfate (THPS) as crosslinking agent to form dynamic covalent bonds with C-PC and SF. The hydrogel exhibited excellent stretchability and compressibility, which with adhesion strength reached 15 ± 3 kPa and rapid self-healing properties. The hydrogel possessed strong antioxidant activity with assessments of DPPH radical-scavenging capacity and total reducing power. In addition, the hydrogel possessed obvious coagulation function and good blood compatibility, which also showed strong antibacterial activity against E. coli and S. aureus. To improve the therapeutic effect, polydeoxyribonucleotide (PDRN) with the ability of promote wound healing was introduced into the hydrogel. The results showed that the hydrogel loading with PDRN possessed high biocompatibility and can promote cell migration. More importantly, the hydrogel loaded with PDRN can effectively promote wound healing by exerting anti-inflammatory and antioxidant effects, which may offer promising potential application value in the field of wound dressing and tissue repair.

Plant-based polymers hold promising prospects thanks to their bioactivity, diversity and versatility but they are currently overshadowed by synthetic and animal-derived materials, especially in biomedical applications. In this study, we developed an entirely plant-based hydrogel with improved mechanical performance based on TEMPO-oxidized cellulose nanofibrils (TCNFs) and the polysaccharide fraction (AVPF) extracted from Aloe vera L. (Aloe barbadensis Miller). The hydrogel blends exhibited excellent viscoelastic properties, minimal shrinkage and a significant increase in compressive modulus (ranging from 2.7 to 13.2 kPa versus 0.8 kPa in single component hydrogels), suggesting a synergistic effect. In-depth analysis of interaction and morphology of the hydrogels by QCM-D, AFM and SEM imaging showed that the observed synergy was the result of the complementary action between the two components and a uniform spatial distribution of the two networks. TCNFs built the rigid skeleton for the hydrogels, while AVPF physically adsorbed on TCNFs, forming a flexible matrix, allowing for better load transfer and dissipation in both static and dynamic loading, leading to a remarkable increase in moduli that surpassed the mere sum of the two individual components. In addition, the obtained hydrogels also showed little to no perceptible shrinkage after drying, unlike the single-component hydrogels made from the initial materials. These hydrogels offer a sustainable and ethical alternative to animal-derived materials, with great potential in biomedical fields.

The purpose of this study was to investigate the molecular structure of NRG-1 protein and its mechanism of action in adult hypertensive heart failure. The amino acid sequence of NRG-1 protein was analyzed by bioinformatics method. High-throughput sequencing was used to compare NRG-1 gene expression levels in hypertensive patients and healthy controls. Using advanced machine learning algorithms, large amounts of clinical data are analyzed to identify biomarkers associated with heart failure. Specific mutation sites in the molecular structure of NRG-1 protein were found to be significantly correlated with the occurrence of adult hypertensive heart failure. Through training and validation of machine learning models, we successfully identified a set of biomarkers strongly associated with heart failure, including a specific fragment of the NRG-1 protein.

Umami peptides were screened and identified from the enzymatic hydrolysate of Spanish mackerel head and its Maillard reaction products using ultrafiltration, gel chromatography, and LC-MS/MS (Liquid Chromatography-Tandem Mass Spectrometry). The umami properties of these peptides were subsequently evaluated and characterized using electronic tongue analysis and molecular docking. This study is the first to employ enzymatic hydrolysis combined with Maillard reaction for the preparation of umami peptides from Spanish mackerel head. Following this approach, a total of nine novel umami peptides were identified, including five from enzymatic hydrolysate (YDDKIY, ITPDEKGTTF, DAITTDDAGK, LEDGYPKEIQE, DAITPDEKGTTF) and four from Maillard reaction products (KDEGSDV, TPDEKGT, TEKAKGEP, FDAITPDEKGTTF). Sensory evaluation and electronic tongue analysis confirmed their distinct umami properties, with taste recognition thresholds ranging from 0.125 to 0.25 mg/mL. Molecular docking analysis revealed that these peptides interact with the T1R1/T1R3 umami receptor through hydrogen bonding and hydrophobic interactions, with key binding residues identified as Ser150, Ser256, and Glu128. This study provides a novel methodology for screening umami peptides from seafood by-products and lays the groundwork for their application as natural umami enhancers in the food industry.

The purpose of this study was to investigate the predictive value of mitochondrial oxidative stress-related LncRNA in cancer prognosis and immunotherapy response, and to further analyze the molecular structure of ribosomal protein L34 and its interaction mechanism with the protein. We screened lncrnas associated with mitochondrial oxidative stress, evaluated their expression patterns in different cancer types, and analyzed the three-dimensional structure of ribosomal protein L34 and its interaction network with other proteins. In this study, public databases were used to screen out lncrnas associated with mitochondrial oxidative stress. Bioinformatic analysis, including gene expression profile analysis, survival analysis and functional enrichment analysis, was used to evaluate the expression patterns of these lncrnas in different cancer types and their relationship with prognosis. The interacting proteins of ribosomal protein L34 were identified by proteomic techniques. The three-dimensional structure of ribosomal protein L34 and its binding mode with interacting proteins were studied by molecular docking and dynamic simulation methods. The results showed that the screened lncrnas showed significant expression differences in multiple cancer types and were closely related to the survival rate of patients. The three-dimensional structure of ribosomal protein L34 reveals key amino acid residues and binding sites for its interactions with specific proteins. Functional enrichment analysis showed that these lncrnas may affect the development of cancer through regulating oxidative stress response, cell cycle and apoptosis. The interaction network of ribosomal protein L34 reveals its central role in protein synthesis and cellular stress response.

This study identified the amino acid sequences of peptides generated from the enzymatic hydrolysis of goat milk proteins from two different sources and annotated their functional activities. Peptidomics and molecular docking approaches were used to investigate the antioxidant and ACE inhibitory properties of the unique peptides, revealing the molecular mechanisms underlying their bioactivity. In vitro experiments showed that the IC50 values for ACE inhibition of the four peptides (LSMTDTR, QEALELIR, NIPVGILR, and QAQNVQHY) were 2.087, 7.584, 2.845, and 4.884 mg/mL, respectively, while the IC50 values for DPPH radical scavenging were 4.466, 4.496, 4.626, and 3.875 mg/mL, respectively, indicating strong antioxidant and ACE inhibitory potential. These findings suggest that goat milk protein could serve as a promising natural source of bioactive peptides with therapeutic potential for managing oxidative stress and hypertension.

Linear dextrin (LD), a low-molecular-weight carbohydrate, regarded as a type of short amylose, can form resistant starch when combined with fatty acids. This study investigated the structural properties and in vitro digestion of linear dextrins and their complexes with lauric acid (LA). Four groups of linear dextrins were prepared by pretreating gelatinized high-amylose maize starch (HAMS) with pullulanase followed by gradient ethanol precipitation at concentrations of 0 %, 50 %, 60 %, and 70 % (v/v). The GPC results showed that the weight average molecular weight (M_w) of these linear dextrins were 425.88 kDa, 189.68 kDa, 3.77 kDa and 2.01 kDa, respectively. After linear dextrins were complexed with lauric acid through co-precipitation treatment, the X-ray diffraction data revealed that, except for LD-70-LA, all other complexes formed a V-type structure. The complexing index of the complexes initially increased and then declined with increasing ethanol concentration, reaching a peak value of 41.54 % for LD-50-LA. The LD-0-LA, LD-60-LA and LD-70-LA complexes exhibited weaker anti-digestion properties compared to LD-50-LA, which demonstrated the highest resistant starch content at 52.43 %. This study offers a new approach and application potential for the efficient production of resistant starch.