INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
·
IF 7.7
Yue Guo,Shenglin Sun,Mingfei Gu,Liyue Zhang,Li Cheng,Zhaofeng Li,Caiming Li,Xiaofeng Ban,Yan Hong,Zhengbiao Gu
Linear α-glucan (LG), a linear polymer linked by α-1,4 bonds, has received increasing attention for its potential applications in synthetic polymer production. Notably, the functionality of LG is strongly influenced by its degree of polymerization (DP). In this study, SP and GP were successfully constructed and expressed. The reaction of enzymatic co -polymerization into LG was investigated. The preferred reaction was carried out at 37 °C and pH 7.4 for 72 h, with a maximum conversion rate of 25 %. Afterwards, two approaches were used to modulate the molecular structures of LGs. Firstly, LGs with distinct molecular weights ranging from 1062.33 ± 16.04 g/mol to 5679 ± 80.29 g/mol were obtained by adjusting the substrate/primer ratio during the LG synthesis process. Secondly, two distinct products could be produced by altering the enzyme addition method: short-chain LG with a DP < 10 (64.34 ± 0.54 %) or long-chain LG with a DP > 45 (45.57 ± 2.18 %). Additionally, theoretical synthesis model was constructed which subdivided the reaction into three stages to evaluate this dual-enzyme cooperative system. These findings have significant implications in promoting the application of LG in the fields of biomedicine and material science.
研究领域:
生物化学
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材料科学
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生物医药
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DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Dan Li,Wenqi Xu,Siyu Mu,Xusheng Gao,Fumin Ma,Cuicui Duan,Xiaolei Li
To explore the roles of loops around active pocket in the reuteran type 4,6-α-glucanotransferase (StGtfB) from S. thermophilus, they were individually or simultaneously replaced with those of an isomalto/maltopolysaccharides type 4,6-α-glucanotransferase from L. reuteri. StGtfB with the replaced loops A1, A2 (A1A2) and A1, A2, B (A1A2B), respectively, showed 1.41- and 0.83-fold activities of StGtfB. Two mutants reduced crystallinity and increased starch disorder at 2, 4, and 8 U/g more than StGtfB and increased DP ≤ 5 short branches of starch by 38.01% at 2 U/g, much more than StGtfB by 4.24%. A1A2B modified starches had the lowest retrogradation over 14 days. A1A2 modified starches had the highest percentage of slowly digestible fractions, ranging from 40.32% to 43.34%. StGtfB and its mutants bind substrates by hydrogen bonding and van der Waals forces at their nonidentical amino acid residues, suggesting that loop replacement leads to a different conformation and changes activity and product structure.
研究领域:
生物化学
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食品科学
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分子生物学
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DOI
PubMed
高影响因子
FOOD HYDROCOLLOIDS
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2022
·
IF 11.504
Xiaoxiao Li,Yu Wang,Jing Wu,Zhengyu Jin,Lubbert Dijkhuizen,Maher Abou Hachem,Yuxiang Bai
Solid-liquid thermo-reversibility, lacking in raw starch is an important property for gels allowing repeated thermal processing in food . In this work, the Thermoproteus uzoniensis 4-α-glucanotransferase (TuαGT) was used to modify five different starches from potato, corn , rice, wheat, and pea and the thermo-reversibility of the modified starch gels was evaluated by rheological assay. Only modified potato starch (MPS) exhibited thermo-reversibility, which prompted us to perform detailed analyses of the structural and gel properties of this product. The enzymatic modification resulted in a marked decrease in amylopectin side chains with a degree of polymerization (DP) < 23, while the contents of side chains with DP 23–43 increased. These data indicated that TuαGT preferentially extended the outer chains of amylopectin using amylose as a donor, which resulted in 17% increase in the amylopectin molecular weight to 3.0 × 10 7 g/mol. Notably, MPS displayed a delayed retrogradation and improved stability in four freeze-thaw cycles (−70 °C and 25 °C) as compared to the native starch. These analyses supported a model to explain the TuαGT catalyzed conversion of potato starch to a thermo-reversible product. Importantly, the MPS thermo-reversible 6% (w/v) gel showed comparable rheological properties to a 1.5% (w/v) κ-carrageenan hydrocolloid , highlighting the potential of MPS as a substitute to κ-carrageenan and other hydrocolloids of emerging health concerns. This work offers a starch based thermo-reversible gel and a methodological framework to broadens the use of starch into novel application as a food ingredient.
研究领域:
食品科学
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生物化学
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DOI
高影响因子
STARCH-STARKE
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2019
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IF 1.795
Li Zhoukun,Zheng Wenwen,Zhang Lei,Wang Yanxin,Zhang Yajuan,Qiao Yan,Luo Xue,Huang Yan,Cui Zhongli
The enzyme 4-α-glucanotransferase catalyzes the intramolecular and intermolecular transglycosylation of α-1,4-glucan, which plays an important role in starch metabolism and starch modification. In this study, the gene encoding a 4-α-glucanotransferase from Corallococcus sp. EGB ( ccGtase ) is cloned and expressed in Escherichia coli BL21 (DE3). CcGtase contains all the conserved amino acid residues of glycoside hydrolase family 77 (GH77), which form the active site environment of the enzymes in the α-amylase family, while sequence alignments show that 4-α-glucanotransferases from myxobacteria constitute an independent group along with the GH77 glucanotransferases. Product analysis shows that CcGtase is able to convert malto-oligosaccharides and starch into linear maltooligosaccharides with a low degree of polymerization (DP < 12) instead of cycloamylose. The transfer action toward starch is only observed in the presence of glucose, and delayed production of maltose from the transfer reaction is also observed. During the reaction, no apparent hydrolytic activity is observed. Based on the low sequence identity (9–35%) and unique characteristics, CcGtase can be regarded as a new member of the GH77 family.
研究领域:
生物化学
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分子生物学
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酶学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
·
IF 8.5
Wei Gao,Ru Yang,Mengli Li,Ming Miao,Tao Zhang
The enzymatic synthesis of amylose is a sustainable solution for the valorisation of non-food cellulose. However, the limited thermostability and catalytic efficiency of existing α -glucan phosphorylases ( α GPs) hinders its potential for industrial scalability. In this study, we identified and characterised a novel α GP from Nicotiana attenuata ( Nicα GP) via genome mining. It exhibited superior catalytic performance, with a specific activity of 82.1 U/mg under optimised conditions (40 °C and pH 5.0), and notable temperature and pH stability. Supplementation of Mg 2+ further enhanced its activity by 5 %. Kinetic analysis revealed a catalytic efficiency ( k cat / K m ) of 27.46 mM −1 s −1 for maltotetraose (G4). Furthermore, a dual-enzyme cascade system integrating Nicα GP with Clostridium thermocellum cellobiose phosphorylase achieved up to 28.4 % cellulose conversion, synthesising amylose with tunable molecular weights (6602 ± 47.13–67,154 ± 47.28 g/mol) by modulating ratios of cellobiose/G4. Molecular docking identified the conserved residues (Gly196, Arg706, Lys711, and Lys821) critical for substrate binding and pyridoxal 5′-phosphate-mediated catalysis. Overall, this study provides a new enzyme component for the artificial synthesis of amylose from non-edible biomass, facilitating the widespread application of non-edible cellulosic resources for food conversion.
研究领域:
生物催化
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工业酶学
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生物质转化
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植物生物技术
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DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2022
·
IF 5.895
Yawen Jiang,Xiaoxiao Li,Tjaard Pijning,Yuxiang Bai,Lubbert Dijkhuizen
Limosilactobacillus reuteri 121 4,6-α-glucanotransferase (Lr121 4,6-α-GTase), belonging to the glycosyl hydrolase (GH) 70 GtfB subfamily, converts starch and maltodextrins into linear isomalto/malto polysaccharides (IMMPs) with consecutive (α1 → 6) linkages. The recent elucidation of its crystal structure allowed identification and analysis of further structural features that determine its reaction and product specificity. Herein, sequence alignments between GtfB enzymes with different product linkage specificities (4,6-α-GTase and 4,3-α-GTase) identified amino acid residues in GH70 homology motifs, which may be critical for reaction and product specificity. Based on these alignments, four Lr121 GtfB-ΔN mutants (I1020M, S1057P, H1056G, and Q1126I) were constructed. Compared to wild-type Lr121 GtfB-ΔN, mutants S1057P and Q1126I had considerably improved catalytic efficiencies. Mutants H1056G and Q1126I showed a 9% decrease and an 11% increase, respectively, in the ratio of (α1 → 6) over (α1 → 4) linkages in maltodextrin-derived products. A change in linkage type (e.g., (α1 → 6) linkages to (α1 → 3) linkages) was not observed. The possible functional roles of these Lr121 GtfB-ΔN residues located around the acceptor substrate-binding subsites are discussed. The results provide new insights into structural determinants of the reaction and product specificity of Lr121 GtfB 4,6-α-GTase.
研究领域:
酶学
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分子生物学
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微生物学
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DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
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2023
·
IF 11.2
Yixi Liu,Yazhen Wu,Hangyan Ji,Xiaoxiao Li,Zhengyu Jin,Birte Svensson,Yuxiang Bai
Isomalto/malto-polysaccharides (IMMPs) derived from malto-oligosaccharides such as maltoheptaose (G7) are elongated non-branched gluco-oligosaccharides produced by 4,6-α-glucanotransferase (GtfB). However, G7 is expensive and cumbersome to produce commercially. In this study, a cost-effective enzymatic process for IMMPs synthesis is developed that utilizes the combined action of cyclodextrinase from Palaeococcus pacificus (PpCD) and GtfB-ΔN from Limosilactobacillus reuteri 121 to convert β-cyclodextrin into IMMPs with a maximum yield (16.19 %, w/w). The purified IMMPs synthesized by simultaneous or sequential treatments, designated as IMMP-Sim and IMMP-Seq, possess relatively high contents of α-(1 → 6) glucosidic linkages. By controlling the release of G7 and smaller malto-oligosaccharides by PpCD, IMMP-Seq was obtained of DP varying from 12.9 to 29.5. Enzymatic fingerprinting revealed different linkage-type distribution of α-(1 → 6) linked segments with α-(1 → 4) segments embedded at the reducing end and middle part. The proportion of α-(1 → 6) segments containing the non-reducing end was 56.76 % for IMMP-Sim but 28.98 % for IMMP-Seq. Addition of G3 or G4 as specific acceptors resulted in IMMPs exhibiting low polydispersity . This procedure can be applied as a novel bioprocess that does not require costy high-purity malto-oligosaccharides and with control of the average DP of IMMPs by adjusting the substrate composition .
研究领域:
生物化学
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食品科学
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PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
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IF 4.192
Yu Wang,Xiaoxiao Li,Hangyan Ji,Danni Zheng,Zhengyu Jin,Yuxiang Bai,Birte Svensson
Gelation of starch is a process during short-term retrogradation. However, long-term retrogradation always leads to the quality deterioration of starch-based food. In this work, a new type of modified tapioca starch (MTS) gel with maintained short-term gelation strength and retarded long-term retrogradation was prepared using a novel recombinantly produced and characterized 4-α-glucanotransferase (TuαGT). In the resulting MTS, the exterior chains of the amylopectin part were elongated and the content of amylose was reduced because of the disproportionation activity of TuαGT. The retrogradation analysis demonstrated that the MTS possessed highly weakened long-term retrogradation characteristics as compared to the native starch. Most importantly, the strength of the gel formed by regelatinized MTS is very close to that of gelatinized native tapioca starch when storing below 30 °C. These findings provide a starting point for developing a novel method for the enzymatic modification of the starch-based gels.
研究领域:
食品科学
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酶学
·
淀粉化学
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DOI
PubMed
高影响因子
Microbiology Spectrum
·
2021
·Vol. 9
·期 3
·
IF 7.171
Alia Rizvi Syeda Kazim,Yuting Jiang,Shengnan Li,Xiaoxiao He
α-Glucan is a major cell wall component and a virulence and adhesion factor for fungal cells. However, the biosynthetic pathway of α-glucan was still unclear. α-Glucan was shown to be composed mainly of 1,3-glycosidically linked glucose, with trace amounts of 1,4-glycosidically linked glucose. Besides the α-glucan synthetases, amylase-like proteins were also important for α-glucan synthesis. In our previous work, we showed that Aspergillus nidulans AmyG was an intracellular protein and was crucial for the proper formation of α-glucan. In the present study, we expressed and purified AmyG in an Escherichia coli system. Enzymatic characterization found that AmyG mainly functioned as an α-amylase that degraded starch into maltose. AmyG also showed weak glucanotransferase activity. Most intriguingly, supplementation with maltose in shaken liquid medium could restore the α-glucan content and the phenotypic defect of a ΔamyG strain. These data suggested that AmyG functions mainly as an intracellular α-amylase to provide maltose during α-glucan synthesis in A. nidulans.IMPORTANCE Short α-1,4-glucan was suggested as the primer structure for α-glucan synthesis. However, the exact structure and its source remain elusive. AmyG was essential to promote α-glucan synthesis and had a major impact on the structure of α-glucan in the cell wall. Data presented here revealed that AmyG belongs to the GH13_5 family and showed strong amylase function, digesting starch into maltose. Supplementation with maltose efficiently rescued the phenotypic defect and α-glucan deficiency in an ΔamyG strain but not in an ΔagsB strain. These results provide the first piece of evidence for the primer structure of α-glucan in fungal cells, although it might be specific to A. nidulans.
研究领域:
微生物学
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分子生物学
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真菌遗传学
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细胞壁生物学
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Yiling Chen,Yong Qin,Haixin Yi,Xiaoyu Cui,Xu Wang,Xiangyu Xu,Yongmei Chen,Fuchuan Li,Wenshuang Wang
Glucans, as versatile biomacromolecules, hold significant application potential across various industries. Volutharpa ampullacea perryi , an affordable deep-sea gastropod, demonstrates considerable commercial promise. In this study, a novel sulfated α-glucan (VpG) was isolated and identified from Volutharpa ampullacea perryi for the first time. Compared to other α-sulfated glucans, it has a high degree of sulfation (18.6 %) and an ultra-high molecular weight of approximately 2250 kDa. Further NMR analysis, including 1 H, 13 C, COSY, TOCSY, HSQC and HMBC, revealed that the anomeric signals at 5.35 ppm dominated. Therefore, VpG is mainly consisted of a repeating α-(1 → 4)-linked glucose backbone with β-(1 → 6) and β-(1 → 3)-linked glucosyl branches. Furthermore, bioactivity evaluation demonstrated that VpG significantly alleviates inflammation in dextran sulfate sodium-induced mouse models of ulcerative colitis, effectively inhibiting body weight loss by 20 % and colon shortening by 31.26 %. The strong anti-inflammatory activity of VpG indicates its potential in pharmaceutical development and provides a novel approach for the high-value utilization of Volutharpa ampullacea perryi .
研究领域:
天然产物化学
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糖生物学
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炎症免疫学
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药物开发
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海洋生物资源利用
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DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Nana Wang,Jingjing Dong,Xiaoxiao Li,Birte Svensson,Zhengyu Jin,Yuxiang Bai
Limosilactobacillus reuteri 121 4,6-α-glucanotransferase GtfB (Lr 121 GtfB), belonging to glycoside hydrolase family 70 (GH70), synthesizes linear isomalto/malto polysaccharides having (α1→6) linkages attached to the nonreducing ends of (α1→4) linked maltose oligosaccharide segments using starch or maltodextrin as a substrate. Since Lr 121 GtfB has low catalytic activity and efficiency, it leads to substrate regeneration and reduced substrate utilization. In this study, we superimposed the crystal structure of Lr 121 GtfB-ΔNΔV with that of L. reuteri NCC 2613 GtfB-ΔNΔV (Lr 2613 GtfB-ΔNΔV) to identify the acceptor binding subsites +1 to +3 and constructed five single-residue mutants and a random mutagenesis of N1019. Compared with the wild-type, N1019D Lr 121 GtfB-ΔN did not alter the product specificity, increased the catalytic activity and efficiency by 420 and 590%, respectively, and maintained >80% relative activity in the pH 3.5–6.5 interval. The findings will contribute to the industrial application of Lr 121 GtfB and provide new solutions for starch synthesis of higher value derivatives.
研究领域:
微生物学
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生物化学
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酶学
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生物技术
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
·
IF 7.7
Jin-Jin Liu,Yu-Ke Hou,Xin Wang,Wei-Wei He,Xiao-Jun Huang,Jun-Yi Yin,Shao-Ping Nie
Polysaccharides are the important bioactive macromolecules in Agrocybe cylindracea , but their changes are as yet elusive during developmental process. This study investigated the dynamic changes of polysaccharides from A. cylindracea fruiting body water extract at four developmental stages and its structure characteristics. Results revealed that the polysaccharides from A. cylindracea water extract significantly increased at the pileus expansion stage and the increased fraction could be α-glucan. The further purification and identification indicated that this α-glucan was a glycogen. It had typical morphology of β particles with a molecular weight of 1375 kDa. Its backbone comprised α-D-(1 → 4)-Glc p and α-D-(1 → 4,6)-Glc p residues at a ratio of 5:1, terminated by α-D-Glc p residue. Rheological behavior suggested that it was a Newtonian fluid at the concentration of 1 %. In addition, despite both the glycogen and natural starch were composed of d -glucose, they exhibited the entirely distinct Maltese cross characteristic and unique crystalline structure. This study is the first to demonstrate the presence of abundant glycogen in the pileus expansion stage of A. cylindracea , which provides new insights on the change patterns of fungal polysaccharides.
研究领域:
真菌学
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生物化学
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食品科学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）