PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 5Citation - Scopus: 6Sequence Identification and in Silico Characterization of Novel Thermophilic Lipases From Geobacillus Species(WILEY, 2023) Sürmeli, Yusuf; Tekedar, Hasan Cihad; Sanli-Mohamed, GulsahMicrobial lipases are utilized in various biotechnological areas, including pharmaceuticals, food, biodiesel, and detergents. In this study, we cloned and sequenced Lip21 and Lip33 genes from Geobacillus sp. GS21 and Geobacillus sp. GS33, then we in silico and experimentally analyzed the encoded lipases. For this purpose, Lip21 and Lip33 were cloned, sequenced, and their amino acid sequences were investigated for determination of biophysicochemical characteristics, evolutionary relationships, and sequence similarities. 3D models were built and computationally affirmed by various bioinformatics tools, and enzyme-ligand interactions were investigated by docking analysis using six ligands. Biophysicochemical property of Lip21 and Lip33 was also determined experimentally and the results demonstrated that they had similar isoelectric point (pI) (6.21) and T-m (75.5(degrees)C) values as T-m was revealed by denatured protein analysis of the circular dichroism spectrum and pI was obtained by isoelectric focusing. Phylogeny analysis indicated that Lip21 and Lip33 were the closest to lipases from Geobacillus sp. SBS-4S and Geobacillus thermoleovorans, respectively. Alignment analysis demonstrated that S144-D348-H389 was catalytic triad residues in Lip21 and Lip33, and enzymes possessed a conserved Gly-X-Ser-X-Gly motif containing catalytic serine. 3D structure analysis indicated that Lip21 and Lip33 highly resembled each other and they were alpha/beta hydrolase-fold enzymes with large lid domains. BAN Delta IT analysis results showed that Lip21 and Lip33 had higher thermal stability, compared to other thermostable Geobacillus lipases. Docking results revealed that Lip21- and Lip33-docked complexes possessed common residues (H112, K115, Q162, E163, and S141) that interacted with the substrates, except paranitrophenyl (pNP)-C10 and pNP-C12, indicating that these residues might have a significant action on medium and short-chain fatty acid esters. Thus, Lip21 and Lip33 can be potential candidates for different industrial applications.Article Citation - WoS: 3Citation - Scopus: 4Enhanced Thermostability of the Immobilized Thermoalkalophilic Esterase Onto Magnetic-Cornstarch Nanoparticle(Wiley, 2022) Öz, Yasin; Sürmeli, Yusuf; Şanlı Mohamed, GülşahThe immobilization of the biocatalysts onto magnetic nanoparticles has been extensively applied as the external magnetic field facilitates the enzyme recovery from the reaction mixture. In the present study, glutaraldehyde-modified magnetite-cornstarch nanoparticles (MCNs) were successfully synthesized, elaborately characterized by ZetaSizer and surface-enhanced Raman spectroscopy, and used for the immobilization of a thermoalkalophilic esterase from Geobacillus sp. The optimal immobilization conditions were obtained at 65 degrees C, 2:3 molar ratios of Fe2+:Fe3+, and 1 g cornstarch resulted in approximately 90 nm magnetic particles in size. Also, immobilization yield and immobilization efficiency of the esterase were found as 74% and 82%, respectively. Scanning electron microscopy micrographs showed that MCNs were uniform, spherical in shape, and well dispersed and esterase immobilized MCNs displayed similar morphology as free MCNs. The maximum activity of free and immobilized esterase was obtained at 65 degrees C and pH 9. Immobilization onto glutaraldehyde-modified MCNs significantly enhanced the esterase thermostability. Additionally, the immobilized esterase kept its residual activity of 75% after three sequential cycles, suggesting that it has favorable operational stability.