Lan J

References (7)

Title : Extracellular Expression of Feruloyl Esterase and Xylanase in Escherichia coli for Ferulic Acid Production from Agricultural Residues - Lan_2023_Microorganisms_11_
Author(s) : Lan J , Ji S , Yang C , Cai G , Lu J , Li X
Ref : Microorganisms , 11 : , 2023
Abstract : There is still a large amount of ferulic acid (FA), an outstanding antioxidant, present in agricultural residues. Enzymatic hydrolysis has been regarded as the most effective way to release FA. This present study therefore selected feruloyl esterase (FAE) and xylanase (XYN) from the metagenomes of a cow rumen and a camel rumen, respectively, for their recombinant expression in Escherichia coli BL21 and further application in releasing FA. After screening the candidate signal peptides, the optimal one for each enzyme, which were selected as SP1 and SP4, respectively, was integrated into the vectors pET22b(+) and pETDuet-1. Among the generated E. coli strains SP1-F, SP4-X, and SP1-F-SP4-X that could express extracellular enzymes either separately or simultaneously, the latter one performed the best in relation to degrading the biomass and releasing FA. Under the optimized culture and induction conditions, the strain SP1-F-SP4-X released 90% of FA from 10% of de-starched wheat bran and produced 314.1 mg/L FA, which was deemed to be the highest obtained value to the best of our knowledge. This result could pave a way for the re-utilization of agricultural residues and enhancing their add-value.
ESTHER : Lan_2023_Microorganisms_11_
PubMedSearch : Lan_2023_Microorganisms_11_
PubMedID: 37630429

Title : Rapid screening for acetylcholinesterase inhibitors in Selaginella doederleinii Hieron by using functionalized magnetic Fe(3)O(4) nanoparticles - Zhang_2022_Talanta_243_123284
Author(s) : Zhang F , Li S , Liu C , Fang K , Jiang Y , Zhang J , Lan J , Zhu L , Pang H , Wang G
Ref : Talanta , 243 :123284 , 2022
Abstract : Insufficient acetylcholine (ACh) can cause cognitive and memory dysfunction, clinically known as, Alzheimer's disease (AD). Acetylcholinesterase (AChE) can hydrolyze ACh into acetic acid and inactivate choline. Therefore, inhibiting the activity of AChE would help to improve the effectiveness of AD treatment. Currently, the methods for rapid screening of AChE inhibitors are limited. This study reports the application of AChE-immobilized magnetic nanoparticles as a drug screening tool to screen AChE inhibitors for natural products. First, AChE was immobilized on a surface of amino-modified magnetic nanoparticles using covalent binding and the AChE concentration, and the pH as well as time was optimized to obtain the maximum enzyme immobilization yield (61.4 microg/mg), and the kinetic model indicated that AChE-immobilized magnetic nanoparticles and the substrate had the high affinity and specificity. Then, a ligand fishing experiment was carried out using a mixed model of tacrine (an inhibitor of AChE) and caffeic acid (a non-inhibitor of AChE) to verify the specificity of the immobilized AChE, and the conditions for ligand fishing were further optimized. Finally, the optimized immobilized AChE was combined with UPLC-MS to screen for AChE inhibitors in Selaginella doederleinii Hieron extracts. Four compounds were confirmed to be potent AChE inhibitors. Among the four compounds, amentoflavone had a stronger AChE inhibitory effect than tacrine (positive control) with an IC(50) of 0.73 +/- 0.009 micromol/L. The results showed that AChE-functionalized magnetic nanoparticles can be used in the discovery of target drugs from complex matrices.
ESTHER : Zhang_2022_Talanta_243_123284
PubMedSearch : Zhang_2022_Talanta_243_123284
PubMedID: 35255433

Title : High-efficiency degradation of phthalic acid esters (PAEs) by Pseudarthrobacter defluvii E5: Performance, degradative pathway, and key genes - Chen_2021_Sci.Total.Environ_794_148719
Author(s) : Chen F , Chen Y , Chen C , Feng L , Dong Y , Chen J , Lan J , Hou H
Ref : Sci Total Environ , 794 :148719 , 2021
Abstract : Phthalic acid esters (PAEs) are a class of biologically accumulated carcinogenic and teratogenic toxic chemicals that exist widely in the environment. This study, Pseudarthrobacter defluvii E5 was isolated from agricultural soils and showed efficient PAEs-degradation and -mineralization abilities for five PAEs, and encouraging PAEs tolerance and bioavailable range for dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) (0.25-1200 mg/L). The complete catalytic system in E5 genome enables PAEs to be degraded into monoester, phthalate (PA) and Protocatechuic acid (PCA), which eventually enter the tricarboxylic acid cycle (TCA cycle). The preferred PAEs-metabolic pathway in soil by E5 is the metabolism induced by enzymes encoded by pehA, mehpH, pht Operon and pca Operon. For the first time, two para-homologous pht gene clusters were found to coexist on the plasmid and contribute to PAEs degradation. Further study showed that P. defluvii E5 has a broad application prospect in microplastics-contaminated environments.
ESTHER : Chen_2021_Sci.Total.Environ_794_148719
PubMedSearch : Chen_2021_Sci.Total.Environ_794_148719
PubMedID: 34214821

Title : Selective synthesis of functionalized quinazolinone derivatives via biocatalysis - Lan_2020_Mol.Catal_498_111261
Author(s) : Lan J , Le Z , Li H , Meng J , Gong B , Xie Z
Ref : Molecular Catalysis , 498 :111261 , 2020
Abstract : A novel and efficient biocatalyzed methodology for the construction of functionalized quinazolinone derivatives via tandem / hydrolysis / decarboxylation / cyclization and transesterification reactions has been developed that works with a variety of 2-aminobenzamide and beta-dicarbonyl compounds. This method requires mild conditions, and has demonstrated high catalytic activity, excellent yields, excellent chemoselectivity, and a broad substrate scope. Additionally, biocatalyzed decarboxylation does not require high temperatures or light activation, giving it a substantial advantage over alternative techniques. Most importantly, it offers a new example for the exploration of simple, convenient, and environmentally friendly synthetic routes utilizing enzymes in organic chemistry.
ESTHER : Lan_2020_Mol.Catal_498_111261
PubMedSearch : Lan_2020_Mol.Catal_498_111261

Title : Structural and functional analyses of the lipase CinB from Enterobacter asburiae - Shang_2019_Biochem.Biophys.Res.Commun_519_274
Author(s) : Shang F , Lan J , Liu W , Chen Y , Wang L , Zhao J , Chen J , Gao P , Ha NC , Quan C , Nam KH , Xu Y
Ref : Biochemical & Biophysical Research Communications , 519 :274 , 2019
Abstract : Lipases are widely present in various plants, animals and microorganisms, constituting a large category of enzymes. They have the ability to catalyze the cleavage of ester bonds. The lipase CinB from Enterobacter asburiae (E. asburiae) is an acetyl esterase. The primary amino acid sequence suggests that the EaCinB protein belongs to the alpha/beta-hydrolase (ABH) superfamily of the esterase/lipase superfamily. However, its molecular functions have not yet been determined. Here, we report the crystal structure of E. asburiae CinB at a 1.45A resolution. EaCinB contains a signal peptide, cap domain and catalytic domain. The active site of EaCinB contains the catalytic triad (Ser180-His307-Asp277) on the catalytic domain. The oxyanion hole is composed of Gly106 and Gly107 within the conserved sequence motif HGGG (amino acid residues 106-109). The substrate is accessible between the alpha1 and alpha2 helices or the alpha1 helix and catalytic domain. Narrow substrate pockets are formed by the alpha2 helix of the cap domain. Site-directed mutagenesis showed that EaCinB-W208H exhibits a higher catalytic ability than EaCinB-WT by approximately nine times. Our results provide insight into the molecular function of EaCinB.
ESTHER : Shang_2019_Biochem.Biophys.Res.Commun_519_274
PubMedSearch : Shang_2019_Biochem.Biophys.Res.Commun_519_274
PubMedID: 31493870
Gene_locus related to this paper: entas-cinB

Title : Structural definition of a neutralization epitope on the N-terminal domain of MERS-CoV spike glycoprotein - Zhou_2019_Nat.Commun_10_3068
Author(s) : Zhou H , Chen Y , Zhang S , Niu P , Qin K , Jia W , Huang B , Lan J , Zhang L , Tan W , Wang X
Ref : Nat Commun , 10 :3068 , 2019
Abstract : Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). The epitopes and mechanisms of mAbs targeting non-RBD regions have not been well characterized yet. Here we report the monoclonal antibody 7D10 that binds to the N-terminal domain (NTD) of the spike glycoprotein and inhibits the cell entry of MERS-CoV with high potency. Structure determination and mutagenesis experiments reveal the epitope and critical residues on the NTD for 7D10 binding and neutralization. Further experiments indicate that the neutralization by 7D10 is not solely dependent on the inhibition of DPP4 binding, but also acts after viral cell attachment, inhibiting the pre-fusion to post-fusion conformational change of the spike. These properties give 7D10 a wide neutralization breadth and help explain its synergistic effects with several RBD-targeting antibodies.
ESTHER : Zhou_2019_Nat.Commun_10_3068
PubMedSearch : Zhou_2019_Nat.Commun_10_3068
PubMedID: 31296843

Title : Structural insight into the carboxylesterase BioH from Klebsiella pneumoniae - Wang_2019_Biochem.Biophys.Res.Commun_520_538
Author(s) : Wang L , Chen Y , Shang F , Liu W , Lan J , Gao P , Ha NC , Nam KH , Dong Y , Quan C , Xu Y
Ref : Biochemical & Biophysical Research Communications , 520 :538 , 2019
Abstract : The BioH carboxylesterase which is a typical alpha/beta-hydrolase enzyme involved in biotin synthetic pathway in most bacteria. BioH acts as a gatekeeper and blocks the further elongation of its substrate. In the pathogen Klebsiella pneumoniae, BioH plays a critical role in the biosynthesis of biotin. To better understand the molecular function of BioH, we determined the crystal structure of BioH from K. pneumoniae at 2.26A resolution using X-ray crystallography. The structure of KpBioH consists of an alpha-beta-alpha sandwich domain and a cap domain. B-factor analysis revealed that the alpha-beta-alpha sandwich domain is a rigid structure, while the loops in the cap domain shows the structural flexibility. The active site of KpBioH contains the catalytic triad (Ser82-Asp207-His235) on the interface of the alpha-beta-alpha sandwich domain, which is surrounded by the cap domain. Size exclusion chromatography shows that KpBioH prefers the monomeric state in solution, whereas two-fold symmetric dimeric formation of KpBioH was observed in the asymmetric unit, the conserved Cys31-based disulfide bonds can maintain the irreversible dimeric formation of KpBioH. Our study provides important structural insight for understanding the molecular mechanisms of KpBioH and its homologous proteins.
ESTHER : Wang_2019_Biochem.Biophys.Res.Commun_520_538
PubMedSearch : Wang_2019_Biochem.Biophys.Res.Commun_520_538
PubMedID: 31615653
Gene_locus related to this paper: klep3-bioh