scholarly journals Computational Design of Nitrile Hydratase from Pseudonocardia thermophila JCM3095 for Improved Thermostability

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4806
Author(s):  
Zhongyi Cheng ◽  
Yao Lan ◽  
Junling Guo ◽  
Dong Ma ◽  
Shijin Jiang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rational Design ◽  
Nitrile Hydratase ◽  
Elevated Temperatures ◽  
Residual Activity ◽  
Fold Increase ◽  
Computational Design ◽  
Site Directed Mutagenesis ◽  
Multiple Point ◽  
Substrate Affinity

High thermostability and catalytic activity are key properties for nitrile hydratase (NHase, EC 4.2.1.84) as a well-industrialized catalyst. In this study, rational design was applied to tailor the thermostability of NHase from Pseudonocardia thermophila JCM3095 (PtNHase) by combining FireProt server prediction and molecular dynamics (MD) simulation. Site-directed mutagenesis of non-catalytic residues provided by the rational design was subsequentially performed. The positive multiple-point mutant, namely, M10 (αI5P/αT18Y/αQ31L/αD92H/βA20P/βP38L/βF118W/βS130Y/βC189N/βC218V), was obtained and further analyzed. The Melting temperature (Tm) of the M10 mutant showed an increase by 3.2 °C and a substantial increase in residual activity of the enzyme at elevated temperatures was also observed. Moreover, the M10 mutant also showed a 2.1-fold increase in catalytic activity compared with the wild-type PtNHase. Molecular docking and MD simulations demonstrated better substrate affinity and improved thermostability for the mutant.

scholarly journals Ability of Ectoine to Stabilize Lipase against Elevated Temperatures and Methanol Concentrations

2021 ◽  
Vol 21 (2) ◽  
pp. 494
Author(s):  
I Putu Parwata ◽  
Deana Wahyuningrum ◽  
Sony Suhandono ◽  
Rukman Hertadi
Keyword(s):  
Catalytic Activity ◽  
Lipase Activity ◽  
Organic Molecules ◽  
Elevated Temperatures ◽  
Residual Activity ◽  
Final Concentration ◽  
Methanol Treatment ◽  
Highly Effective

Ectoine is one of the compatible organic molecules that can protect the protein from heating, freezing, and chemicals contact. This study aims to investigate the ability of ectoine to stabilize lipase on heating and in methanol treatments as an effort to provide a stable biocatalyst for the production of biodiesel. Various ectoine concentrations were added to lipase solutions, then the mixture was heated, and the residual activity of the lipase was determined. Similar steps were also conducted for methanol treatment. The results showed that ectoine maintained and even improved the catalytic activity of lipase after treatment with either heat or methanol. The addition of ectoine to a final concentration of 110 to 150 mM could maintain lipase activity up to 80% when heating to approximately 95 °C. Additionally, more than 20% of lipase activity increased on heating to temperatures below 75 °C in the presence of ectoine at a final concentration of 25 to 120 mM. Meanwhile, after incubation in methanol at a level of around 84% (v/v), the activity of lipase containing 40–90 mM ectoine was maintained. These results demonstrated that ectoine was highly effective in protecting lipase from heat and methanol.

Improved catalytic activity and stability of cellobiohydrolase (Cel6A) from the Aspergillus fumigatus by rational design

2020 ◽  
Vol 33 ◽  
Author(s):  
Subba Reddy Dodda ◽  
Nibedita Sarkar ◽  
Piyush Jain ◽  
Kaustav Aikat ◽  
Sudit S Mukhopadhyay
Keyword(s):  
Catalytic Activity ◽  
Protein Engineering ◽  
Aspergillus Fumigatus ◽  
Rational Design ◽  
Catalytic Efficiency ◽  
Kinetic Studies ◽  
Substrate Affinity ◽  
Wild Type ◽  
Dynamics Simulations ◽  
Cellulose Binding

Abstract Cheap production of glucose is the current challenge for the production of cheap bioethanol. Ideal protein engineering approaches are required for improving the efficiency of the members of the cellulase, the enzyme complex involved in the saccharification process of cellulose. An attempt was made to improve the efficiency of the cellobiohydrolase (Cel6A), the important member of the cellulase isolated from Aspergillus fumigatus (AfCel6A). Structure-based variants of AfCel6A were designed. Amino acids surrounding the catalytic site and conserved residues in the cellulose-binding domain were targeted (N449V, N168G, Y50W and W24YW32Y). I mutant 3 server was used to identify the potential variants based on the free energy values (∆∆G). In silico structural analyses and molecular dynamics simulations evaluated the potentiality of the variants for increasing thermostability and catalytic activity of Cel6A. Further enzyme studies with purified protein identified the N449V is highly thermo stable (60°C) and pH tolerant (pH 5–7). Kinetic studies with Avicel determined that substrate affinity of N449V (Km =0.90 ± 0.02) is higher than the wild type (1.17 ± 0.04) and the catalytic efficiency (Kcat/Km) of N449V is ~2-fold higher than wild type. All these results suggested that our strategy for the development of recombinant enzyme is a right approach for protein engineering.

scholarly journals Enhancement of a protocol purifying T1 lipase through molecular approach

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5833
Author(s):  
Che Haznie Ayu Che Hussian ◽  
Raja Noor Zaliha Raja Abd. Rahman ◽  
Adam Leow Thean Chor ◽  
Abu Bakar Salleh ◽  
Mohd Shukuri Mohamad Ali
Keyword(s):  
Rational Design ◽  
Double Point ◽  
Specific Activity ◽  
Point Mutations ◽  
Fold Increase ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Site Directed Mutagenesis ◽  
Glutathione S Transferase ◽  
Direct Separation

T1 Lipase is a thermostable secretary protein of Geobacillus zalihae strain previously expressed in a prokaryotic system and purified using three-step purification: affinity 1, affinity 2, and ion exchange chromatography (IEX). This approach is time consuming and offers low purity and recovery yield. In order to enhance the purification strategy of T1 lipase, affinity 2 was removed so that after affinity 1, the cleaved Glutathione S-transferase (GST) and matured T1 lipase could be directly separated through IEX. Therefore, a rational design of GST isoelectric point (pI) was implemented by prediction using ExPASy software in order to enhance the differences of pI values between GST and matured T1 lipase. Site-directed mutagenesis at two locations flanking the downstream region of GST sequences (H215R and G213R) was successfully performed. Double point mutations changed the charge on GST from 6.10 to 6.53. The purified lipase from the new construct GST tag mutant-T1 was successfully purified using two steps of purification with 6,849 U/mg of lipase specific activity, 33% yield, and a 44-fold increase in purification. Hence, the increment of the pI values in the GST tag fusion T1 lipase resulted in a successful direct separation through IEX and lead to successful purification.

scholarly journals Heterologous Expression and Rational Design of l-asparaginase from Rhizomucor miehei to Improve Thermostability

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1346
Author(s):  
Xian Zhang ◽  
Zhi Wang ◽  
Yimai Wang ◽  
Xu Li ◽  
Manchi Zhu ◽  
...  
Keyword(s):  
Rational Design ◽  
Scale Up ◽  
Residual Activity ◽  
Rhizomucor Miehei ◽  
Site Directed Mutagenesis ◽  
Wild Type ◽  
Fed Batch ◽  
Wild Type Enzyme ◽  
Bacillus Subtilis 168 ◽  
Fed Batch Fermentation

l-asparaginase (EC 3.5.1.1) hydrolyzes l-asparagine to produce l-aspartate and ammonia and is widely found in microorganisms, plants, and some rodent sera. l-asparaginase used for industrial production should have good thermostability. We heterologously expressed l-asparaginase from Rhizomucor miehei, selected nine loci for site-directed mutagenesis by rational design, and obtained two mutants with significantly improved thermostability. The optimal temperature of mutants S302I and S302M was 50 °C. After incubating the mutant and wild-type enzymes at 45 °C for 35 h, the residual activity of the wild-type enzyme (WT) was only about 10%. In contrast, the residual activity of S302I and S302M was more than 50%. After combination mutagenesis, Bacillus subtilis 168-pMA5-A344E/S302I was constructed using the food-safe host strain B. subtilis 168. Additionally, a 5′ untranslated region (UTR) modification strategy was adopted to enhance the expression level of R. miehei-derived l-asparaginase in B. subtilis. In a 5-L fermenter scale-up experiment, the enzyme activity of recombinant B. subtilis 168-pMA5-UTR-A344E/S302I reached 521.9 U·mL−1 by fed-batch fermentation.

scholarly journals Hydroxylation of Steroids by a Microbial Substrate-Promiscuous P450 Cytochrome (CYP105D7): Key Arginine Residues for Rational Design

2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Bingbing Ma ◽  
Qianwen Wang ◽  
Haruo Ikeda ◽  
Chunfang Zhang ◽  
Lian-Hua Xu
Keyword(s):  
Active Site ◽  
Rational Design ◽  
Molecular Mechanisms ◽  
Fold Increase ◽  
Site Directed Mutagenesis ◽  
Cytochrome P450 Monooxygenases ◽  
Content Type ◽  
Conversion Rates ◽  
Arginine Residues

ABSTRACT Our previous study showed that CYP105D7, a substrate-promiscuous P450, catalyzes the hydroxylation of 1-deoxypentalenic acid, diclofenac, naringenin, and compactin. In this study, 14 steroid compounds were screened using recombinant Escherichia coli cells harboring genes encoding CYP105D7 and redox partners (Pdx/Pdr, RhFRED, and FdxH/FprD), and the screening identified steroid A-ring 2β- and D-ring 16β-hydroxylation activity. Wild-type CYP105D7 was able to catalyze the hydroxylation of five steroids (testosterone, progesterone, 4-androstene-3,17-dione, adrenosterone, and cortisone) with low (<10%) conversion rates. Structure-guided site-directed mutagenesis of arginine residues around the substrate entrance and active site showed that the R70A and R190A single mutants and an R70A/R190A double mutant exhibited greatly enhanced conversion rates for steroid hydroxylation. For the conversion of testosterone in particular, the R70A/R190A mutant's kcat/Km values increased 1.35-fold and the in vivo conversion rates increased significantly by almost 9-fold with high regio- and stereoselectivity. Molecular docking analysis revealed that when Arg70 and Arg190 were replaced with alanine, the volume of the substrate access and binding pocket increased 1.08-fold, which might facilitate improvement of the hydroxylation efficiency of steroids. IMPORTANCE Cytochrome P450 monooxygenases (P450s) are able to introduce oxygen atoms into nonreactive hydrocarbon compounds under mild conditions, thereby offering significant advantages compared to chemical catalysts. Promiscuous P450s with broad substrate specificity and reaction diversity have significant potential for applications in various fields, including synthetic biology. The study of the function, molecular mechanisms, and rational engineering of substrate-promiscuous P450s from microbial sources is important to fulfill this potential. Here, we present a microbial substrate-promiscuous P450, CYP105D7, which can catalyze hydroxylation of steroids. The loss of the bulky side chains of Arg70 and Arg190 in the active site and substrate entrance resulted in an up to 9-fold increase in the substrate conversion rate. These findings will support future rational and semirational engineering of P450s for applications as biocatalysts.

Molecular Design of Peptide-Fc Fusion Drugs

2019 ◽  
Vol 20 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Lin Ning ◽  
Bifang He ◽  
Peng Zhou ◽  
Ratmir Derda ◽  
Jian Huang
Keyword(s):  
Rational Design ◽  
Molecular Design ◽  
Computational Design ◽  
Fusion Technology ◽  
Computational Tools ◽  
Open Questions ◽  
Biological Therapeutics ◽  
Key Steps ◽  
Computational Resources ◽  
Tools And Methods

Background:Peptide-Fc fusion drugs, also known as peptibodies, are a category of biological therapeutics in which the Fc region of an antibody is genetically fused to a peptide of interest. However, to develop such kind of drugs is laborious and expensive. Rational design is urgently needed.Methods:We summarized the key steps in peptide-Fc fusion technology and stressed the main computational resources, tools, and methods that had been used in the rational design of peptide-Fc fusion drugs. We also raised open questions about the computer-aided molecular design of peptide-Fc.Results:The design of peptibody consists of four steps. First, identify peptide leads from native ligands, biopanning, and computational design or prediction. Second, select the proper Fc region from different classes or subclasses of immunoglobulin. Third, fuse the peptide leads and Fc together properly. At last, evaluate the immunogenicity of the constructs. At each step, there are quite a few useful resources and computational tools.Conclusion:Reviewing the molecular design of peptibody will certainly help make the transition from peptide leads to drugs on the market quicker and cheaper.

scholarly journals Enhancing the thermostability and activity of uronate dehydrogenase from Agrobacterium tumefaciens LBA4404 by semi-rational engineering

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Hui-Hui Su ◽  
Fei Peng ◽  
Pei Xu ◽  
Xiao-Ling Wu ◽  
Min-Hua Zong ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Rational Design ◽  
Glucuronic Acid ◽  
Specific Activity ◽  
Value Added ◽  
Catalytic Efficiency ◽  
Site Directed Mutagenesis ◽  
Glucaric Acid ◽  
Triple Mutant ◽  
Pharmaceutical Industries

Abstract Background Glucaric acid, one of the aldaric acids, has been declared a “top value-added chemical from biomass”, and is especially important in the food and pharmaceutical industries. Biocatalytic production of glucaric acid from glucuronic acid is more environmentally friendly, efficient and economical than chemical synthesis. Uronate dehydrogenases (UDHs) are the key enzymes for the preparation of glucaric acid in this way, but the poor thermostability and low activity of UDH limit its industrial application. Therefore, improving the thermostability and activity of UDH, for example by semi-rational design, is a major research goal. Results In the present work, three UDHs were obtained from different Agrobacterium tumefaciens strains. The three UDHs have an approximate molecular weight of 32 kDa and all contain typically conserved UDH motifs. All three UDHs showed optimal activity within a pH range of 6.0–8.5 and at a temperature of 30 °C, but the UDH from A. tumefaciens (At) LBA4404 had a better catalytic efficiency than the other two UDHs (800 vs 600 and 530 s−1 mM−1). To further boost the catalytic performance of the UDH from AtLBA4404, site-directed mutagenesis based on semi-rational design was carried out. An A39P/H99Y/H234K triple mutant showed a 400-fold improvement in half-life at 59 °C, a 5 °C improvement in $$ {\text{T}}_{ 5 0}^{ 1 0} $$ T 50 10 value and a 2.5-fold improvement in specific activity at 30 °C compared to wild-type UDH. Conclusions In this study, we successfully obtained a triple mutant (A39P/H99Y/H234K) with simultaneously enhanced activity and thermostability, which provides a novel alternative for the industrial production of glucaric acid from glucuronic acid.

scholarly journals Computational and Rational Design of Single-Chain Antibody against Tick-Borne Encephalitis Virus for Modifying Its Specificity

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1494
Author(s):  
Ivan K. Baykov ◽  
Pavel Y. Desyukevich ◽  
Ekaterina E. Mikhaylova ◽  
Olga M. Kurchenko ◽  
Nina V. Tikunova
Keyword(s):  
Rational Design ◽  
Fold Increase ◽  
Encephalitis Virus ◽  
Chimeric Antibody ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Glycoprotein E ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Far Eastern

Tick-borne encephalitis virus (TBEV) causes 5−7 thousand cases of human meningitis and encephalitis annually. The neutralizing and protective antibody ch14D5 is a potential therapeutic agent. This antibody exhibits a high affinity for binding with the D3 domain of the glycoprotein E of the Far Eastern subtype of the virus, but a lower affinity for the D3 domains of the Siberian and European subtypes. In this study, a 2.2-fold increase in the affinity of single-chain antibody sc14D5 to D3 proteins of the Siberian and European subtypes of the virus was achieved using rational design and computational modeling. This improvement can be further enhanced in the case of the bivalent binding of the full-length chimeric antibody containing the identified mutation.

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