دانلود رایگان مقاله لاتین یون کلسیم ساختاری بر خواص قارچ از سایت الزویر
عنوان فارسی مقاله:
بینش به تاثیر دو یون کلسیم ساختاری بر خواص قارچ ارینجی لیگنین پراکسیداز همه کاره
عنوان انگلیسی مقاله:
Insight into the impact of two structural calcium ions on the properties of Pleurotus eryngii versatile ligninolytic peroxidase
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Rising energy consumption, depletion of fossil fuels and increasing environmental concerns have shifted the focus of energy generation towards biofuels derived from renewable sources. Lignocellulose, as a renewable organic material, consisting of cellulose, hemicellulose and lignin, is the major structural component of plants [1]. Lignin blocks enzymes to access cellulose and hemicellulose. To maximally utilize carbohydrates in the biomass, a pretreatment process is needed to improve accessibility to hydrolytic enzymes. From both economic and environmental perspectives, pretreatment with lignin-degrading microorganisms or enzymes has received renewed interest as an alternative to thermal/chemical pretreatment [2e4]. It's known that several oxidoreductases secreted by white-rot basidiomycetes are involved in lignin biodegradation, including laccase, lignin peroxidase (LiP), manganese peroxidase (MnP), and versatile peroxidase (VP) [1]. Among them, VP is arousing great interest due to its ability to oxidize a variety of substrates [1]. VP has been described in Pleurotus, Bjerkandera and some other basidiomycetes [5,6]. VP could not only oxidize the substrates that LiP, MnP, and CiP (Coprinopsis cinerea peroxidase) can oxidize like veratryl alcohol, Mn2þ, and simple phenolic compounds, but also some high-redox-potential aromatic compounds which these three enzymes can't oxidize [1]. A lot of studies towards VP have been carried out, including heterologous overexpression [7,8,9], enzymology [5,8], site-directed mutagenesis [9,10], and protein engineering for improved thermal and H2O2 stability [11e14]. VP's crystal structure has been published, contains a heme cofactor located inside an internal cavity, two Ca2þ binding regions, and a Mn2þ binding site, etc. (Fig. 1) [15]. According to the structure of VP, both calcium ions are coordinated by seven oxygen atoms, which is typical for Ca2þ. One calcium ion was reported to be tightly bound on the proximal side of the heme, while the other one was bound on the distal side of heme and considered to be loosely bound [16]. Due to the relative proximity of the calcium ions to the heme, they were proposed to be important for stabilization of the active site of the enzyme. The residues involved in liganding two calcium ions are highly conserved among peroxidases (Fig. 1). It has been found that thermal inactivation of MnP and LiP resulted in loss of distal Ca2 , whereas alkaline treatment of LiP leads to release both Ca2 [16e19]. Therefore, it appears that the distal Ca2þ binding region is related with the thermostability of ligninolytic peroxidases, and both have close relationship with the alkaline stability of ligninolytic peroxidases. Sutherland et al. investigated the role of Asp47 in MnP, one of the ligands of distal Ca2þ. They found that the specific activity of D47A was less than 1% of that of WT MnP, and D47A had only one Ca2þ and the same spectroscopic properties as thermally inactivated MnP [16]. On the basis of the properties and structure of peanut peroxidase, Reading et al. engineered a disulfide bond near the distal calcium binding site of MnP by mutation of Ala48 and Ala63, and the double mutant MnP A48C/A63C was more stable against the effects of temperature and pH than WT [20]. This study suggested that reinforcing the local structure of the distal Ca2þ active site through a disulfide bond would increase enzyme stability. So far, no systematic studies towards the residues involved in two Ca2þ binding pockets of ligninolytic peroxidases have been performed, those liganding the proximal calcium ion in particular. In this study, all residues participating in the two Ca2þ binding regions of Pleurotus eryngii VP were mutated respectively, and the effects of mutagenesis on specific activity, UVevis spectroscopy, pH and thermal stability, Ca2þ contents, and secondary structure were studied.
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کلمات کلیدی:
Insight into the impact of two structural calcium ions on the properties ... https://www.ncbi.nlm.nih.gov/pubmed/27720685 by Y Gao - 2016 - Related articles Oct 5, 2016 - Insight into the impact of two structural calcium ions on the properties of Pleurotus eryngii versatile ligninolytic peroxidase. Gao Y(1), Zheng L(2) ... vpl1 - Versatile peroxidase VPL1 precursor - Pleurotus eryngii ... www.uniprot.org/uniprot/Q9UR19 A versatile ligninolytic peroxidase that combines the substrate specificity characteristics of the two other ligninolytic ... Note: Binds 2 calcium ions per subunit. vpl2 - Versatile peroxidase VPL2 precursor - Pleurotus eryngii ... www.uniprot.org/uniprot/O94753 A versatile ligninolytic peroxidase that combines the substrate specificity characteristics of the two other ligninolytic ... Note: Binds 2 calcium ions per subunit. Insight into the impact of two structural calcium ions on the properties ... https://pubag.nal.usda.gov/catalog/5563464 by Y Gao - 2016 - Related articles ... of residues involved in two Ca2+ on properties of ligninolytic peroxidases have ... two Ca2+ of Pleurotus eryngii versatile peroxidase (VP) were investigated. Manganese Oxidation Site in Pleurotus eryngii Versatile Peroxidase: A ... cdn-pubs.acs.org/doi/full/10.1021/bi061542h Dec 14, 2006 - These include Pleurotus eryngii (8), which produces a third family of ligninolytic peroxidases called “versatile peroxidases” (VP; EC 1.11.1.16) (9). ...... calcium ions on the properties of Pleurotus eryngii versatile ligninolytic ... Manganese Oxidation Site in Pleurotus eryngii Versatile Peroxidase: A ... pubs.acs.org/doi/abs/10.1021/bi061542h by FJ Ruiz-Dueñas - 2007 - Cited by 58 - Related articles Dec 14, 2006 - Enhancing Mn(II)-Binding and Manganese Peroxidase Activity in a ... calcium ions on the properties of Pleurotus eryngii versatile ligninolytic peroxidase ... The ligninolytic peroxidases in the genus Pleurotus: divergence in ...
