Contribution of active site residues to the activity and thermal stability of ribonuclease Sa

Thermal stability is a limiting factor for effective application of D-psicose 3-epimerase (DPEase) enzyme. Recently, it was reported that the thermal stability of DPEase was improved by immobilizing enzymes on graphene oxide (GO) nanoparticles. However, the detailed mechanism is not known. In this study, we investigated interaction details between GO and DPEase by performing molecular dynamics (MD) simulations. The results indicated that the domain (K248 to D268) of DPEase was an important anchor for immobilizing DPEase on GO surface. Moreover, the strong interactions between DPEase and GO can prevent loop α1′-α1 and β4-α4 of DPEase from the drastic fluctuation. Since these two loops contained active site residues, the geometry of the active pocket of the enzyme remained stable at high temperature after the DPEase was immobilized by GO, which facilitated efficient catalytic activity of the enzyme. Our research provided a detailed mechanism for the interaction between GO and DPEase at the nano–biology interface.

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Direct Decomposition of NO into N2 and O2 over Cu /ZSM-5 Containing Ce and Zr as Promoter

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.1735 ◽

2010 ◽

Vol 113-116 ◽

pp. 1735-1739 ◽

Cited By ~ 2

Author(s):

Peng Fei Yang ◽

Ji Cheng Zhou ◽

Zhe Wang

Keyword(s):

Thermal Stability ◽

Ion Exchange ◽

High Activity ◽

Active Site ◽

Direct Decomposition ◽

No Decomposition ◽

Highly Active ◽

Zr Addition ◽

Decomposition Of No ◽

Thermal Stability Of

The Zr-Cu-Ce/ZSM-5 catalysts prepared by the simultaneous ion-exchange showed high activity for NO decomposition in the presence of O2, the highest conversion of NO was up to 75%, indicating that the Ce and Zr addition can enhance the activity of catalysts. A new highly active site, which facilitates oxygen mobilization and desorption, could be formed in the sample due to the Ce and Zr addition. In addition, the Zr addition can significantly improve the thermal stability of the catalyst.

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The influence of active site loop mutations on the thermal stability of azurin from Pseudomonas aeruginosa

Archives of Biochemistry and Biophysics ◽

10.1016/j.abb.2012.03.007 ◽

2012 ◽

Vol 521 (1-2) ◽

pp. 18-23 ◽

Cited By ~ 3

Author(s):

Rita Guzzi ◽

Luigi Sportelli ◽

Sachiko Yanagisawa ◽

Chan Li ◽

Dorota Kostrz ◽

...

Keyword(s):

Thermal Stability ◽

Pseudomonas Aeruginosa ◽

Active Site ◽

Thermal Stability Of

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Evaluation of the role of two conserved active-site residues in Beta class glutathione S-transferases

Biochemical Journal ◽

10.1042/bj3510341 ◽

2000 ◽

Vol 351 (2) ◽

pp. 341-346 ◽

Cited By ~ 9

Author(s):

Nerino ALLOCATI ◽

Enrico CASALONE ◽

Michele MASULLI ◽

Galina POLEKHINA ◽

Jamie ROSSJOHN ◽

...

Keyword(s):

Crystal Structure ◽

Thermal Stability ◽

Catalytic Activity ◽

Proteus Mirabilis ◽

Active Site ◽

Binding Capacity ◽

Active Site Residues ◽

Terminal Domain ◽

Glutathione S Transferases

Glutathione S-transferases (GSTs) normally use hydroxy-group-containing residues in the N-terminal domain of the enzyme for stabilizing the activated form of the co-substrate, glutathione. However, previous mutagenesis studies have shown that this is not true for Beta class GSTs and thus the origin of the stabilization remains a mystery. The recently determined crystal structure of Proteus mirabilis GST B1-1 (PmGST B1-1) suggested that the stabilizing role might be fulfilled in Beta class GSTs by one or more residues in the C-terminal domain of the enzyme. To test this hypothesis we mutated His106 and Lys107 of PmGST B1-1 to investigate their possible role in the enzyme's catalytic activity. His106 was mutated to Ala, Asn and Phe, and Lys107 to Ala and Arg. The effects of the replacement on the activity, thermal stability and antibiotic-binding capacity of the enzyme were examined. The results are consistent with the involvement of His106 and Lys107 in interacting with glutathione at the active site but these residues do not contribute significantly to catalysis, folding or antibiotic binding.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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Microstructure studies of tungsten silicide schottky contacts on Gaas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126445 ◽

1987 ◽

Vol 45 ◽

pp. 328-329

Author(s):

Yih-Cheng Shih ◽

E. L. Wilkie

Keyword(s):

Thermal Stability ◽

Field Effect Transistors ◽

Schottky Contact ◽

Schottky Contacts ◽

Excellent Thermal Stability ◽

Barrier Heights ◽

Gaas Substrates ◽

Film Adhesion ◽

Threshold Voltages ◽

Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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