scholarly journals Assembly of Methyl Coenzyme M Reductase in the Methanogenic ArchaeonMethanococcus maripaludis

2018 ◽  
Vol 200 (7) ◽  
Author(s):  
Zhe Lyu ◽  
Chau-Wen Chou ◽  
Hao Shi ◽  
Liangliang Wang ◽  
Robel Ghebreab ◽  
...  
Keyword(s):  
Heterologous Expression ◽  
Methane Production ◽  
Active Sites ◽  
Net Primary Production ◽  
Expression System ◽  
Anaerobic Oxidation Of Methane ◽  
Coenzyme M ◽  
Heterologous Expression System ◽  
Content Type ◽  
Methyl Coenzyme M Reductase

ABSTRACTMethyl coenzyme M reductase (MCR) is a complex enzyme that catalyzes the final step in biological methanogenesis. To better understand its assembly, the recombinant MCR from the thermophileMethanothermococcus okinawensis(rMCRok) was expressed in the mesophileMethanococcus maripaludis. The rMCRokwas posttranslationally modified correctly and contained McrD and the unique nickel tetrapyrrole coenzyme F430. Subunits of the nativeM. maripaludis(MCRmar) were largely absent, suggesting that the recombinant enzyme was formed by an assembly of cotranscribed subunits. Strong support for this hypothesis was obtained by expressing a chimeric operon comprising the His-taggedmcrAfromM. maripaludisand themcrBDCGfromM. okinawensisinM. maripaludis. The His-tagged purified rMCR then contained theM. maripaludisMcrA and theM. okinawensisMcrBDG. The present study prompted us to form a working model for MCR assembly, which can be further tested by the heterologous expression system established here.IMPORTANCEApproximately 1.6% of the net primary production of plants, algae, and cyanobacteria are processed by biological methane production in anoxic environments. This accounts for about 74% of the total global methane production, up to 25% of which is consumed by anaerobic oxidation of methane (AOM). Methyl coenzyme M reductase (MCR) is the key enzyme in both methanogenesis and AOM. MCR is assembled as a dimer of two heterotrimers, where posttranslational modifications and F430cofactors are embedded in the active sites. However, this complex assembly process remains unknown. Here, we established a heterologous expression system for MCR to learn how MCR is assembled.

scholarly journals Characterization of Leader Processing Shows That Partially Processed Mersacidin Is Activated by AprE After Export

2021 ◽  
Vol 12 ◽  
Author(s):  
Jakob H. Viel ◽  
Amanda Y. van Tilburg ◽  
Oscar P. Kuipers
Keyword(s):  
Antimicrobial Activity ◽  
Synthetic Biology ◽  
Heterologous Expression ◽  
Expression System ◽  
Heterologous Expression System ◽  
Proteolytic Activation ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Precursor Peptide ◽  
Potential Applications

The ribosomally synthesized and post-translationally modified peptide mersacidin is a class II lanthipeptide with good activity against Gram-positive bacteria. The intramolecular lanthionine rings, that give mersacidin its stability and antimicrobial activity, are specific structures with potential applications in synthetic biology. To add the mersacidin modification enzymes to the synthetic biology toolbox, a heterologous expression system for mersacidin in Escherichia coli has recently been developed. While this system was able to produce fully modified mersacidin precursor peptide that could be activated by Bacillus amyloliquefaciens supernatant and showed that mersacidin was activated in an additional proteolytic step after transportation out of the cell, it lacked a mechanism for clean and straightforward leader processing. Here, the protease responsible for activating mersacidin was identified and heterologously produced in E. coli, improving the previously reported heterologous expression system. By screening multiple proteases, the stringency of proteolytic activity directly next to a very small lanthionine ring is demonstrated, and the full two-step proteolytic activation of mersacidin was elucidated. Additionally, the effect of partial leader processing on diffusion and antimicrobial activity is assessed, shedding light on the function of two-step leader processing.

scholarly journals TheNitrosopumilus maritimusCdvB, but Not FtsZ, Assembles into Polymers

Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Kian-Hong Ng ◽  
Vinayaka Srinivas ◽  
Ramanujam Srinivasan ◽  
Mohan Balasubramanian
Keyword(s):  
Cell Division ◽  
Heterologous Expression ◽  
Fission Yeast ◽  
Mammalian Cells ◽  
Expression System ◽  
Related Protein ◽  
Heterologous Expression System

Euryarchaeota and Crenarchaeota are two major phyla of archaea which use distinct molecular apparatuses for cell division. Euryarchaea make use of the tubulin-related protein FtsZ, while Crenarchaea, which appear to lack functional FtsZ, employ the Cdv (cell division) components to divide. Ammonia oxidizing archaeon (AOA)Nitrosopumilus maritimusbelongs to another archaeal phylum, the Thaumarchaeota, which has both FtsZ and Cdv genes in the genome. Here, we used a heterologous expression system to characterize FtsZ and Cdv proteins fromN. maritimusby investigating the ability of these proteins to form polymers. We show that one of the Cdv proteins inN. maritimus, the CdvB (Nmar_0816), is capable of forming stable polymers when expressed in fission yeast. TheN. maritimusCdvB is also capable of assembling into filaments in mammalian cells. However,N. maritimusFtsZ does not assemble into polymers in our system. The ability of CdvB, but not FtsZ, to polymerize is consistent with a recent finding showing that several Cdv proteins, but not FtsZ, localize to the mid-cell site in the dividingN. maritimus. Thus, we propose that it is Cdv proteins, rather than FtsZ, that function as the cell division apparatus inN. maritimus.

scholarly journals Two New Unspecific Peroxygenases from Heterologous Expression of Fungal Genes in Escherichia coli

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Dolores Linde ◽  
Andrés Olmedo ◽  
Alejandro González-Benjumea ◽  
María Estévez ◽  
Chantal Renau-Mínguez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heterologous Expression ◽  
Aromatic Compounds ◽  
Ad Hoc ◽  
Expression System ◽  
Catalytic Efficiency ◽  
Veratryl Alcohol ◽  
Cytochrome P450 Monooxygenases ◽  
Content Type ◽  
Fungal Genes

ABSTRACT Unspecific peroxygenases (UPOs) constitute a new family of fungal heme-thiolate enzymes in which there is high biotechnological interest. Although several thousand genes encoding hypothetical UPO-type proteins have been identified in sequenced fungal genomes and other databases, only a few UPO enzymes have been experimentally characterized to date. Therefore, gene screening and heterologous expression from genetic databases are a priority in the search for ad hoc UPOs for oxyfunctionalization reactions of interest. Very recently, Escherichia coli production of a previously described basidiomycete UPO (as a soluble and active enzyme) has been reported. Here, we explored this convenient heterologous expression system to obtain the protein products from available putative UPO genes. In this way, two UPOs from the ascomycetes Collariella virescens (syn., Chaetomium virescens) and Daldinia caldariorum were successfully obtained, purified, and characterized. Comparison of their kinetic constants for oxidation of model substrates revealed 10- to 20-fold-higher catalytic efficiency of the latter enzyme in oxidizing simple aromatic compounds (such as veratryl alcohol, naphthalene, and benzyl alcohol). Homology molecular models of these enzymes showed three conserved and two differing residues in the distal side of the heme (the latter representing two different positions of a phenylalanine residue). Interestingly, replacement of the C. virescens UPO Phe88 by the homologous residue in the D. caldariorum UPO resulted in an F88L variant with 5- to 21-fold-higher efficiency in oxidizing these aromatic compounds. IMPORTANCE UPOs catalyze regio- and stereoselective oxygenations of both aromatic and aliphatic compounds. Similar reactions were previously described for cytochrome P450 monooxygenases, but UPOs have the noteworthy biotechnological advantage of being stable enzymes requiring only H2O2 to be activated. Both characteristics are related to the extracellular nature of UPOs as secreted proteins. In the present study, the limited repertoire of UPO enzymes available for organic synthesis and other applications is expanded with the description of two new ascomycete UPOs obtained by Escherichia coli expression of the corresponding genes as soluble and active enzymes. Moreover, directed mutagenesis in E. coli, together with enzyme molecular modeling, provided relevant structure-function information on aromatic substrate oxidation by these two new biocatalysts.

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