scholarly journals Importance of Conserved and Variable C-terminal Residues for the Activity and Thermal Stability of the β Subunit of Tryptophan Synthase

1997 ◽  
Vol 272 (12) ◽  
pp. 7859-7866 ◽  
Author(s):  
Li-hong Yang ◽  
S. Ashraf Ahmed ◽  
Sangkee Rhee ◽  
Edith Wilson Miles
Keyword(s):  
Thermal Stability ◽  
Tryptophan Synthase ◽  
Β Subunit ◽  
Thermal Stability Of

Evidence for the participation of an extra α-helix at β-subunit surface in the thermal stability of Co-type nitrile hydratase

2018 ◽  
Vol 102 (18) ◽  
pp. 7891-7900 ◽  
Author(s):  
Xiaolin Pei ◽  
Jiapao Wang ◽  
Yifeng Wu ◽  
Xiaoting Zhen ◽  
Manman Tang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nitrile Hydratase ◽  
Β Subunit ◽  
Α Helix ◽  
Thermal Stability Of

scholarly journals Engineering Improves Enzymatic Synthesis of L-Tryptophan by Tryptophan Synthase from Escherichia coli

2020 ◽  
Vol 8 (4) ◽  
pp. 519
Author(s):  
Lisheng Xu ◽  
Fangkai Han ◽  
Zeng Dong ◽  
Zhaojun Wei
Keyword(s):  
Thermal Stability ◽  
Amino Acid ◽  
Directed Evolution ◽  
Amino Acid Residue ◽  
Rational Design ◽  
Molecular Engineering ◽  
Mutant Enzyme ◽  
Tryptophan Synthase ◽  
Mutant Library ◽  
Thermal Stability Of

To improve the thermostability of tryptophan synthase, the molecular modification of tryptophan synthase was carried out by rational molecular engineering. First, B-FITTER software was used to analyze the temperature factor (B-factor) of each amino acid residue in the crystal structure of tryptophan synthase. A key amino acid residue, G395, which adversely affected the thermal stability of the enzyme, was identified, and then, a mutant library was constructed by site-specific saturation mutation. A mutant (G395S) enzyme with significantly improved thermal stability was screened from the saturated mutant library. Error-prone PCR was used to conduct a directed evolution of the mutant enzyme (G395S). Compared with the parent, the mutant enzyme (G395S /A191T) had a Km of 0.21 mM and a catalytic efficiency kcat/Km of 5.38 mM−1∙s−1, which was 4.8 times higher than that of the wild-type strain. The conditions for L-tryptophan synthesis by the mutated enzyme were a L-serine concentration of 50 mmol/L, a reaction temperature of 40 °C, pH of 8, a reaction time of 12 h, and an L-tryptophan yield of 81%. The thermal stability of the enzyme can be improved by using an appropriate rational design strategy to modify the correct site. The catalytic activity of tryptophan synthase was increased by directed evolution.

Effect of single amino acid substitutions on the thermal stability of the .alpha. subunit of tryptophan synthase

Biochemistry ◽  
1980 ◽  
Vol 19 (7) ◽  
pp. 1290-1293 ◽  
Author(s):  
C. R. Matthews ◽  
M. M. Crisanti ◽  
G. L. Gepner ◽  
G. Velicelebi ◽  
J. M. Sturtevant
Keyword(s):  
Thermal Stability ◽  
Amino Acid ◽  
Alpha Subunit ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Tryptophan Synthase ◽  
Thermal Stability Of

The Ordered Phase Formation in Ti-Al-Ga Alloys

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

Microstructure studies of tungsten silicide schottky contacts on Gaas

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.

Thermal stability of Al-Cu-Fe icosahedral alloys

1991 ◽  
Vol 1 (12) ◽  
pp. 1823-1836 ◽  
Author(s):  
M. Bessière ◽  
A. Quivy ◽  
S. Lefebvre ◽  
J. Devaud-Rzepski ◽  
Y. Calvayrac
Keyword(s):  
Thermal Stability ◽  
Thermal Stability Of

Practical criteria for the thermal stability of a unidimensional superconductor

1994 ◽  
Vol 4 (4) ◽  
pp. 653-657
Author(s):  
B. Bonzi ◽  
M. El Khomssi ◽  
H. Lanchon-Ducauquis
Keyword(s):  
Thermal Stability ◽  
Thermal Stability Of

Time and thermal stability of magnetic properties of amorphous Fe80TM3B17 alloys

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-63-Pr2-66 ◽  
Author(s):  
R. Varga ◽  
P. Vojtaník ◽  
A. Lovas
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Thermal Stability Of

Thermal stability of organic-inorganic nanocomposites based on system of dimethacrylate-tetraethoxysilane and their kinetic features

2016 ◽  
Vol 38 (3) ◽  
pp. 211-217
Author(s):  
G.I. Khovanets’ ◽  
◽  
O.Y. Makido ◽  
V.V. Kochubey ◽  
Y.G. Medvedevskikh ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Inorganic Nanocomposites ◽  
Thermal Stability Of ◽  
Kinetic Features
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