INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2022
·Vol. 23
·期 13
·6928
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IF 6.208
Meixing Wang,Huizhen Hu,Buyu Zhang,Yang Zheng,Pan Wu,Zhenghui Lu,Guimin Zhang
Panose is a type of functional sugar with diverse bioactivities. The enzymatic conversion bioprocess to produce high purity panose with high efficiency has become increasingly important. Here, a new neopullulanase (NPase), Amy117 fromB. pseudofirmus703, was identified and characterized. Amy117 presented the optimal activity at pH 7.0 and 30 °C, its activity is over 40% at 10 °C and over 80% at 20 °C, which is cold-active. The enzyme cleaved α-1, 4-glycosidic linkages of pullulan to generate panose as the only hydrolysis product, and degraded cyclodextrins (CDs) and starch to glucose and maltose, with an apparent preference for CDs. Furthermore, Amy117 can produce 72.7 mg/mL panose with a conversion yield of 91% (w/w) based on 80 mg/mL pullulan. The sequence and structure analysis showed that the low proportion of Arg, high proportion of Asn and Gln, and high α-helix levels in Amy117 may contribute to its cold-active properties. Root mean square deviation (RMSD) analysis also showed that Amy117 is more flexible than two mesophilic homologues. Hence, we discovered a new high-efficiency panose-producing NPase, which so far achieves the highest panose production and would be an ideal candidate in the food industry.Keywords:neopullulanase (NPase);pullulan;panose production;high-efficiency
研究领域:
食品科学
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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
BIORESOURCE TECHNOLOGY
·
2023
·
IF 11.4
Ailin Zhang,Yanhua Hou,Yatong Wang,Quanfu Wang,Xuejing Shan,Jianan Liu
To eliminate efficiency restriction of polyethylene microplastics low-temperature biodegradation, a novel InaKN-mediated Escherichia coli surface display platform for cold-active degrading laccase PsLAC production was developed. Display efficiency of 88.0% for engineering bacteria BL21/pET-InaKN-PsLAC was verified via subcellular extraction and protease accessibility, exhibiting an activity load of 29.6 U/mg. Cell growth and membrane integrity revealed BL21/pET-InaKN-PsLAC maintained stable growth and intact membrane structure during the display process. The favorable applicability was confirmed, with 50.0% activity remaining in 4 days at 15 °C, and 39.0% activity recovery retention after 15 batches of activity substrate oxidation reactions. Moreover, BL21/pET-InaKN-PsLAC possessed high polyethylene low-temperature depolymerizing capacity. Bioremediation experiments proved that the degradation rate was 48.0% within 48 h at 15 °C, and reached 66.0% after 144 h. Collectively, cold-active PsLAC functional surface display technology and its significant contributions to polyethylene microplastics low-temperature degradation constitute an effective improvement strategy for biomanufacturing and microplastics cold remediation.
研究领域:
环境生物学
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微生物学
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生物技术
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Brenda Bezus,Juan Carlos Contreras Esquivel,Sebastián Cavalitto,Ivana Cavello
An Antarctic yeast was cultivated to produce and enzymatic extract with polygalacturonase activity, whose biochemical properties were studied. It assisted pectin extraction from lime pomace at 20 °C. The extract produced by Tausonia pullulans 8E had an optimum temperature of 40 °C and optimum pH of 5.0. At 20 °C, it displayed 54% of relative activity. A good pH-stability and thermostability were observed. Hg +2 and Co +2 inhibited its activity in 40 and 11%, respectively. Pectin was obtained from lime pomace at 20 °C, with 15% of yield after 120 min extraction. Uronic acid (46%) and neutral sugars (53%) were determined. Pectin's molecular weight was estimated in the order of 100,000 g mol −1 . By anion-exchange chromatography, pectin-linked and free neutral sugars were observed. The high-methoxyl pectin was used to prepare low-calorie gels. It was demonstrated that this cold-active enzyme allows enzymatic-assisted pectin extraction at 20 °C.
研究领域:
食品科学
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生物技术
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生物化学
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酶学
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DOI
PubMed
高影响因子
ACTA BIOCHIMICA ET BIOPHYSICA SINICA
·
2018
·Vol. 50
·期 6
·547-554
·
IF 2.224
Jia Qian,Lin Yun,Gou Xuejing,He Lei,Shen Dong,Chen Dongni,Xie Wei,Lu Yongjun
The gram-negative bacterium Legionella pneumophila invades human’s lung and causes Legionnaires’ disease. To benefit its survival and replication in cellular milieu, L. pneumophila secrets at least 330 effector proteins into host cells. We found that the effector WipA has the protein tyrosine phosphatase (PTP) activity but does not depend on the classical CX5R motif for activity, suggesting that WipA is an unconventional PTP. Meanwhile, the presence of three other highly conserved motifs typically seen in protein serine/threonine phosphatases and the poor inhibition of WipA activity by okadaic acid led us to propose that WipA is a bacterial protein phosphatase. In addition, the determination of the 2.55-Å crystal structure of WipA revealed that WipA resembles cold-active protein tyrosine phosphatase (CAPTPase), and therefore very likely shares the same catalytic mechanism.
研究领域:
微生物学
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分子生物学
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传染病学
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结构生物学
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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）