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Wei X, Huang W, Teng M, Shen H, Feng B, Chen L, Yang F, Wang L, Yu S. Allosteric regulation of α-amylase induced by ligands binding. Int J Biol Macromol 2023:125131. [PMID: 37257525 DOI: 10.1016/j.ijbiomac.2023.125131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023]
Abstract
The conformational changes in α-amylase induced by different ligands, including metal ions, substrates, and aromatic compounds in liquor production, were systematically studied using spectroscopy. Fluorescence acrylamide quenching analysis showed that the interaction with active metal cations (K+, Na+, and Ca2+) led to higher exposure of the active sites in α-amylase. In contrast, interactions with substrates (soluble starch, amylose, amylopectin, wheat starch, and dextrin) reduced the degree of exposure of active sites, and the conformation of the enzyme became more rigid and compact. Although the interaction with inhibitory metal cations (Mg2+, Zn2+) and aromatic compounds generated in the brewing process (guaiacol, eugenol, thymol, and vanillin) increased the exposure of active site with a relatively low amplitude, it reduced the enzymatic activity. This finding may be due to the overall structure of the enzyme becoming looser. Structural stability showed that the active cations and substrates increased the stability of the secondary structure of the α-amylase backbone, whereas the inhibitory cations and aromatic compounds reduced the stability of the backbone but increased the compact of domain A and B. Enzymatic assays and molecular docking experiments strongly supported these conclusions. The experimental results may provide a valuable reference for controlling related conditions and improving production efficiency.
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Affiliation(s)
- Xinfei Wei
- Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Wanqiu Huang
- Kweichow Moutai Group, Renhuai, Guizhou 564501, China
| | - Mengjing Teng
- Kweichow Moutai Group, Renhuai, Guizhou 564501, China
| | - Hao Shen
- Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Bin Feng
- Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | | | - Fan Yang
- Kweichow Moutai Group, Renhuai, Guizhou 564501, China.
| | - Li Wang
- Kweichow Moutai Group, Renhuai, Guizhou 564501, China
| | - Shaoning Yu
- Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
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Kand D, Kalle AM, Talukdar P. Chromenoquinoline-based thiol probes: a study on the quencher position for controlling fluorescent Off-On characteristics. Org Biomol Chem 2013; 11:1691-701. [PMID: 23364761 DOI: 10.1039/c2ob27192c] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The design, synthesis and thiol sensing ability of chromenoquinoline-based fluorescent probes 4, 5 and 6 and are reported here. The relative position of the maleimide moiety was varied along the chromenoquinoline fluorophore to decrease the background fluorescence. Lower background fluorescence in probes 4 and 6 was rationalized by the smaller k(r)/k(nr) values compared to that of probe 5. An intramolecular charge transfer (ICT) mechanism was proposed for quenching and the extent was dependent on the position of the maleimide quencher. Fluorescent Off-On characteristics were evaluated by theoretical calculations. All probes were selective only towards thiol containing amino acids. Thiol sensing by probes 4 and 6 were much better compared to 5. Probe 4 displayed a better fluorescence response for less hindered thiol (185-, 223- and 156-fold for Hcy, Cys and GSH, respectively), while for probe 6, a higher enhancement in fluorescence was observed with more hindered thiols (180-, 205- and 245-fold for Hcy, Cys and GSH, respectively). The better response to bulkier thiol, GSH by probe 6 was attributed to the steric crowding at the C-4 position and bulkiness of the GSH group which force the succinimide unit to be in a nearly orthogonal conformation. This spatial arrangement was important in reducing the fluorescence quenching ability of the succinimide moiety. The application of probes 4, 5 and 6 was demonstrated by naked eye detection thiols using a 96-well plate system as well as by live-cell imaging.
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Affiliation(s)
- Dnyaneshwar Kand
- Department of Chemistry, Dmitri Mendeleev Block, Indian Institute of Science Education and Research, Pune, India
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Hao L, Wang R, Fang K, Liu J. Ultrasonic effect on the desizing efficiency of α-amylase on starch-sized cotton fabrics. Carbohydr Polym 2013; 96:474-80. [DOI: 10.1016/j.carbpol.2013.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 10/27/2022]
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