Dataset Information

Influence of Calcium Ions on the Thermal Characteristics of ?-amylase from Thermophilic Anoxybacillus sp. GXS-BL.

ABSTRACT: BACKGROUND:?-Amylases are starch-degrading enzymes and used widely, the study on thermostability of ?-amylase is a central requirement for its application in life science and biotechnology. OBJECTIVE:In this article, our motivation is to study how the effect of Ca2+ ions on the structure and thermal characterization of ?-amylase (AGXA) from thermophilic Anoxybacillus sp.GXS-BL. METHODS:?-Amylase activity was assayed with soluble starch as the substrate, and the amount of sugar released was determined by DNS method. For AGXA with calcium ions and without calcium ions, optimum temperature (Topt), half-inactivation temperature (T50) and thermal inactivation (halflife, t1/2) was evaluated. The thermal denaturation of the enzymes was determined by DSC and CD methods. 3D structure of AGXA was homology modeled with ?-amylase (5A2A) as the template. RESULTS:With calcium ions, the values of Topt, T50, t1/2, Tm and ?H in AGXA were significantly higher than those of AGXA without calcium ions, showing calcium ions had stabilizing effects on ?-amylase structure with the increased temperature. Based on DSC measurements AGXA underwent thermal denaturation by adopting two-state irreversible unfolding processes. Based on the CD spectra, AGXA without calcium ions exhibited two transition states upon unfolding, including ?- helical contents increasing, and the transition from ?-helices to ?-sheet structures, which was obviously different in AGXA with Ca2+ ions, and up to 4 Ca2+ ions were located on the inter-domain or intra-domain regions according to the modeling structure. CONCLUSION:These results reveal that Ca2+ ions have pronounced influences on the thermostability of AGXA structure.

SUBMITTER: Liao SM

PROVIDER: S-EPMC6416487 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Influence of Calcium Ions on the Thermal Characteristics of α-amylase from Thermophilic Anoxybacillus sp. GXS-BL.

Liao Si-Ming SM Liang Ge G Zhu Jing J Lu Bo B Peng Li-Xin LX Wang Qing-Yan QY Wei Yu-Tuo YT Zhou Guo-Ping GP Huang Ri-Bo RB

Protein and peptide letters 20190101 2

<h4>Background</h4>α-Amylases are starch-degrading enzymes and used widely, the study on thermostability of α-amylase is a central requirement for its application in life science and biotechnology.<h4>Objective</h4>In this article, our motivation is to study how the effect of Ca2+ ions on the structure and thermal characterization of α-amylase (AGXA) from thermophilic Anoxybacillus sp.GXS-BL.<h4>Methods</h4>α-Amylase activity was assayed with soluble starch as the substrate, and the amount of su ...[more]

PMID: 30652633

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Project description:Four closely related facultative anaerobe, moderately thermophilic, Gram positive rods (JS1(T), JS5, JS11, and JS15) were isolated from sediment samples from a hot spring at Suryakund, Jharkhand, India. Colonies were pale yellow, rough surface with uneven edges on TSA after 72 h incubation. Heterotrophic growth was observed at 40-60°C and pH 5.5-11.5; optimum growth occurred at 55°C and pH 7.5. 16S rRNA gene sequence analysis revealed the strains belong to genus Anoxybacillus. DNA-DNA homology values among strains were above 70% and showed distinct ERIC and REP PCR profile. On the basis of morphology and biochemical characteristics, strain JS1(T) was studied further. Strain JS1(T) showed 99.30% sequence similarity with A. flavithermus subsp. yunnanensis, 99.23% with A. mongoliensis, 99.16% with A. eryuanensis, 98.74% with A. flavithermus subsp. flavithermus, 98.54% with A. tengchongensis, 98.51% with A. pushchinoensis, 97.91% with A. thermarum, 97.82% with A. kaynarcensis, 97.77% with A. ayderensis and A. kamchatkensis, 97.63% with A. salavatliensis, 97.55% with A. kestanbolensis, 97.48% with A. contaminans, 97.27% with A. gonensis and 97.17% with A. voinovskiensis. In 16S rRNA secondary structure based phylogenetic comparison, strain JS1(T) was clustered with Anoxybacillus eryuanensis, A. mongoliensis, and A. flavithermus subsp. yunnanensis and showed 15 species specific base substitutions with maximum variability in helix 6. Moreover, DNA-DNA relatedness between JS1(T) and the closely related type strains were well below 70%. The DNA G+C content was 42.1 mol%. The major fatty acids were C(15:0 iso), C(16:0 iso) and C(17:0iso). The polar lipids were a phosphatidylgylycerol, a diphosphatidylglycerol, a phosphatidylethnolamine, a phosphatidylcholine, a phosphatidyl monomethylethanolamine and four unknown lipids. Based on polyphasic approach, strain JS1(T) represent a novel species of the genus Anoxybacillus for which Anoxybacillus suryakundensis sp. nov. is proposed. The type strain is JS1(T) (= DSM 27374(T) = LMG 27616(T) =JCM19211(T)).

Dataset Information

Influence of Calcium Ions on the Thermal Characteristics of ?-amylase from Thermophilic Anoxybacillus sp. GXS-BL.

Publications

Influence of Calcium Ions on the Thermal Characteristics of α-amylase from Thermophilic Anoxybacillus sp. GXS-BL.

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