Saturation mutagenesis in selected amino acids to shift Pseudomonas sp. acidic lipase Lip I.3 substrate specificity and activity

2015 ◽  
Vol 51 (7) ◽  
pp. 1330-1333 ◽  
Author(s):  
Paola Panizza ◽  
Silvia Cesarini ◽  
Pilar Diaz ◽  
Sonia Rodríguez Giordano

Several Pseudomonas sp. CR611 Lip I.3 mutants with overall increased activity and a shift towards longer chain substrates were constructed.




2018 ◽  
Vol 84 (23) ◽  
Author(s):  
Efstratios Nikolaivits ◽  
Maria Dimarogona ◽  
Ioanna Karagiannaki ◽  
Angelina Chalima ◽  
Ayelet Fishman ◽  
...  

ABSTRACTPolyphenol oxidases (PPOs) have been mostly associated with the undesirable postharvest browning in fruits and vegetables and have implications in human melanogenesis. Nonetheless, they are considered useful biocatalysts in the food, pharmaceutical, and cosmetic industries. The aim of the present work was to characterize a novel PPO and explore its potential as a bioremediation agent. A gene encoding an extracellular tyrosinase-like enzyme was amplified from the genome ofThermothelomyces thermophilaand expressed inPichia pastoris. The recombinant enzyme (TtPPO) was purified and biochemically characterized. Its production reached 40 mg/liter, and it appeared to be a glycosylated and N-terminally processed protein.TtPPO showed broad substrate specificity, as it could oxidize 28/30 compounds tested, including polyphenols, substituted phenols, catechols, and methoxyphenols. Its optimum temperature was 65°C, with a half-life of 18.3 h at 50°C, while its optimum pH was 7.5. The homology model ofTtPPO was constructed, and site-directed mutagenesis was performed in order to increase its activity on mono- and dichlorophenols (di-CPs). The G292N/Y296V variant ofTtPPO 5.3-fold increased activity on 3,5-dichlorophenol (3,5-diCP) compared to the wild type.IMPORTANCEA novel fungal PPO was heterologously expressed and biochemically characterized. Construction of single and double mutants led to the generation of variants with altered specificity against CPs. Through this work, knowledge is gained regarding the effect of mutations on the substrate specificity of PPOs. This work also demonstrates that more potent biocatalysts for the bioremediation of harmful CPs can be developed by applying site-directed mutagenesis.



2007 ◽  
Vol 282 (44) ◽  
pp. 32397-32405 ◽  
Author(s):  
Fabrice Neiers ◽  
Sanjiv Sonkaria ◽  
Alexandre Olry ◽  
Sandrine Boschi-Muller ◽  
Guy Branlant




2011 ◽  
Vol 7 (11) ◽  
pp. 3050 ◽  
Author(s):  
Kinjal Rajesh Mehta ◽  
Ching Yao Yang ◽  
Jin Kim Montclare


Author(s):  
Jolanta Cieślak ◽  
Akimasa Miyanaga ◽  
Makoto Takaishi ◽  
Fumitaka Kudo ◽  
Tadashi Eguchi

Adenylation enzymes play an important role in the selective incorporation of the cognate carboxylate substrates in natural product biosynthesis. Here, the biochemical and structural characterization of the adenylation enzyme IdnL7, which is involved in the biosynthesis of the macrolactam polyketide antibiotic incednine, is reported. Biochemical analysis showed that IdnL7 selects and activates several small amino acids. The structure of IdnL7 in complex with an L-alanyl-adenylate intermediate mimic, 5′-O-[N-(L-alanyl)sulfamoyl]adenosine, was determined at 2.1 Å resolution. The structure of IdnL7 explains the broad substrate specificity of IdnL7 towards small L-amino acids.



Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 747
Author(s):  
Samah Hashim Albayati ◽  
Malihe Masomian ◽  
Siti Nor Hasmah Ishak ◽  
Mohd Shukuri bin Mohamad Ali ◽  
Adam Leow Thean ◽  
...  

Microbial lipases represent one of the most important groups of biotechnological biocatalysts. However, the high-level production of lipases requires an understanding of the molecular mechanisms of gene expression, folding, and secretion processes. Stable, selective, and productive lipase is essential for modern chemical industries, as most lipases cannot work in different process conditions. However, the screening and isolation of a new lipase with desired and specific properties would be time consuming, and costly, so researchers typically modify an available lipase with a certain potential for minimizing cost. Improving enzyme properties is associated with altering the enzymatic structure by changing one or several amino acids in the protein sequence. This review detailed the main sources, classification, structural properties, and mutagenic approaches, such as rational design (site direct mutagenesis, iterative saturation mutagenesis) and direct evolution (error prone PCR, DNA shuffling), for achieving modification goals. Here, both techniques were reviewed, with different results for lipase engineering, with a particular focus on improving or changing lipase specificity. Changing the amino acid sequences of the binding pocket or lid region of the lipase led to remarkable enzyme substrate specificity and enantioselectivity improvement. Site-directed mutagenesis is one of the appropriate methods to alter the enzyme sequence, as compared to random mutagenesis, such as error-prone PCR. This contribution has summarized and evaluated several experimental studies on modifying the substrate specificity of lipases.



2007 ◽  
Vol 282 (28) ◽  
pp. 20484-20491 ◽  
Author(s):  
Adeline Gand ◽  
Mathias Antoine ◽  
Sandrine Boschi-Muller ◽  
Guy Branlant


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