Production of Lysinibacillus sphaericus Mosquitocidal Protein Mtx2 from Bacillus subtilis as a Secretory Protein

Background: Mtx2 is a mosquitocidal toxin produced during the vegetative growth of Lysinibacillus sphaericus. The protein shows synergism with other toxins against mosquito larvae; hence it could be used in mosquito control formulations. The protein expression system is needed for Mtx2 development as a biocontrol agent. Objective: The objective of the study was to set up a Bacillus subtilis system to produce Mtx2 as a secreted protein since the protein contains a putative signal peptide. Methods: Initially, four different promoters (P43, Pspac, PxylA, and PyxiE) were compared for their strength using GFP as a reporter in B. subtilis. Subsequently, six different signal peptides (SacB, Epr, AmyE, AprE, LipA, and Vip3A)were tested in conjunction with the selected promoter and mtx2 to evaluate levels of Mtx2 secreted by B. subtilis WB800, an extracellular protease-deficient strain. Results: The promoter PyxiE showed the highest GFP intensity and was selected for further study. Mtx2 was successfully produced as a secreted protein from signal peptides LipA and AmyE, and exhibited larvicidal activity against Aedesaegypti. Conclusion: B. subtilis was successfully developed as a host for the production of secreted Mtx2 and the protein retained its larvicidal activity. Although the Mtx2 production level still needs improvement, the constructed plasmids could be used to produce other soluble proteins.

Carbonic Anhydrase in Pacific Abalone Haliotis discus hannai: Characterization, Expression, and Role in Biomineralization

Carbonic anhydrases (CAs) are universal zinc ion containing metalloenzymes that play a pivotal role in various physiological processes. In this study, a CA I (designated as Hdh CA I) was isolated and characterized from the mantle tissue of Pacific abalone, Haliotis discus hannai. The full-length cDNA sequence of Hdh CA I was 1,417-bp in length, encoding a protein of 337 amino acids with molecular weight of 37.58 kDa. Hdh CA I sequence possessed a putative signal peptide of 22 amino acids and a CA catalytic function domain. The predicted protein shared 94 and 78% sequence identities with Haliotis gigantea and Haliotis tuberculata CA I, respectively. Results of phylogenetic analysis indicated that Hdh CA I was evolutionarily close to CA I of H. gigantea and H. tuberculata with high bootstrap values. Significantly higher levels of Hdh CA I mRNA transcript were found in mantle than other examined tissues. In situ hybridization results showed strong hybridization signals in epithelial cells of the dorsal mantle pallial, an area known to synthesize and secrete proteins responsible for the nacreous layer formation of shell. This is the first study on Hdh CA I in H. discus hannai and the results may contribute to further study its physiological functions in shell biomineralization of abalone.

An FMRFamide Neuropeptide in Cuttlefish Sepia pharaonis: Identification, Characterization, and Potential Function

Neuropeptides are released by neurons that are involved in a wide range of brain functions, such as food intake, metabolism, reproduction, and learning and memory. A full-length cDNA sequence of an FMRFamide gene isolated from the cuttlefish Sepia pharaonis (designated as SpFMRFamide) was cloned. The predicted precursor protein contains one putative signal peptide and four FMRFamide-related peptides. Multiple amino acid and nucleotide sequence alignments showed that it shares 97% similarity with the precursor FMRFamides of Sepiella japonica and Sepia officinalis and shares 93% and 92% similarity with the SpFMRFamide gene of the two cuttlefish species, respectively. Moreover, the phylogenetic analysis also suggested that SpFMRFamide and FMRFamides from S. japonica and S. officinalis belong to the same sub-branch. Tissue expression analysis confirmed that SpFMRFamide was widely distributed among tissues and predominantly expressed in the brain at the three development stages. The combined effects of SpFMRFamide+SpGnRH and SpFLRFamide+SpGnRH showed a marked decrease in the level of the total proteins released in the CHO-K1 cells. This is the first report of SpFMRFamide in S. pharaonis and the results may contribute to future studies of neuropeptide evolution or may prove useful for the development of aquaculture methods for this cuttlefish species.

Characterization of HTATIP2 and its role during hair follicle cycles in Angora rabbit

Hair follicle (HF) growth and cycling is a complex biological process that occurs in most mammals. As HF growth and cycling directly impacts rabbit wool yield, it is important to better understand the potential regulation pattern of HF development. Our previous study demonstrated that HTATIP2 may participate in regulating rabbit HF cycles, but the molecular mechanism of HTATIP2 remained unclear. In this study, the coding sequence of the HTATIP2 gene in Angora rabbit was cloned. The length of the coding region sequence was 840 bp, which could code 279 amino acids, and exhibited high homology in different mammals. Bioinformatics analyses indicated that the HTATIP2 protein is stable, hydrophilic, located around the cytoplasm, and has a putative signal peptide. Moreover, we verified that HTATIP2 is highly expressed during catagen and telogen of the HF cycle. The overexpression vector was constructed and siRNAs were designed. Overexpression and knockdown of HTATIP2 appeared to regulate JAK-STAT pathway genes, such as BCL2, CCND1, c-Myc, and STAT2. It is therefore likely that HTATIP2 promotes cell apoptosis and inhibits cell proliferation. Our results indicate that HTATIP2 is highly expressed during catagen and telogen and may play an important role in JAK-STAT signaling. This study provides a theoretical foundation for investigating HTATIP2 in biological processes.

Crystal structures of plant inorganic pyrophosphatase, an enzyme with a moonlighting autoproteolytic activity

Inorganic pyrophosphatases (PPases, EC 3.6.1.1), which hydrolyze inorganic pyrophosphate to phosphate in the presence of divalent metal cations, play a key role in maintaining phosphorus homeostasis in cells. DNA coding inorganic pyrophosphatases from Arabidopsis thaliana (AtPPA1) and Medicago truncatula (MtPPA1) were cloned into a bacterial expression vector and the proteins were produced in Escherichia coli cells and crystallized. In terms of their subunit fold, AtPPA1 and MtPPA1 are reminiscent of other members of Family I soluble pyrophosphatases from bacteria and yeast. Like their bacterial orthologs, both plant PPases form hexamers, as confirmed in solution by multi-angle light scattering and size-exclusion chromatography. This is in contrast with the fungal counterparts, which are dimeric. Unexpectedly, the crystallized AtPPA1 and MtPPA1 proteins lack ∼30 amino acid residues at their N-termini, as independently confirmed by chemical sequencing. In vitro, self-cleavage of the recombinant proteins is observed after prolonged storage or during crystallization. The cleaved fragment corresponds to a putative signal peptide of mitochondrial targeting, with a predicted cleavage site at Val31–Ala32. Site-directed mutagenesis shows that mutations of the key active site Asp residues dramatically reduce the cleavage rate, which suggests a moonlighting proteolytic activity. Moreover, the discovery of autoproteolytic cleavage of a mitochondrial targeting peptide would change our perception of this signaling process.

Expression of Xylanase Gene from Pyromyces finnis in Pichia pastoris and Characterization of Recombinant Protein

The heterologous expression and characteristics of a new xylanase from Pyromyces finnis have been described. The endo-l,4-β-xylanase XylP (EC 3.2.1.8) consists of 223 amino acids and 19 residues of a putative signal peptide in the N-terminal region. The amino acid sequence of the mature protein has the greatest homology with the sequence of the native catalytic N-terminal domain of Neocallimastix patriciarum endo-l,4-β-xylanase (84%). A synthetic nucleotide sequence encoding a mature XylP protein was expressed in Pichia pastoris. The purified recombinant enzyme showed activity with birch xylan and arabinoxylan. When using birch xylan as a substrate, the optimum pH for the enzyme was 5.0, and the optimum temperature was 50 °C. The specific activity of the xylanase was 4700 U/mg protein, and Km and Vmax were equal to 0.51 mg/mL and 7395.3 umol/(min∙mg), respectively. The recombinant XylP protein showed moderate thermal stability and high pH stability, resistance to digestive enzymes and protein inhibitors of grain xylanases. It was also shown that the Mg2+, Co2+ and Li+ ions have a positive effect on the enzyme activity. xylanase, xylan, feed enzyme, Pichia pastoris, Pyromyces finnis The work was performed with the financial support of the Ministry of Education and Science of Russia (Unique Project Identifier RFMEFI60717X0180) using the Unique Scientific Installation -National Bioresource Center «All-Russian Collection of Industrial Microorganisms», NRC «Kurchatov Institute» - GOSNIIGENETIKA

Expression of Gene for β-glucanase from Paenibacillus jamilae Bg1 in Pichia pastoris and Characteristics of Recombinant Enzyme

The isolation, heterologous expression and characterization of a new thermostable β-glucanase from Paenibacillus jamilae is described. The bgl26 gene from the P. jamilae Bg1 VKPM B-13093 strain consisting of 714 nucleotides encodes endo-1,3-1,4-β-glucanase (EC 3.2.1.73) containing 213 amino acids and 24 residues of the putative signal peptide in N-end area. The nucleotide sequence of the bgl26 gene and the amino acid sequence of the mature Bgl26 protein have the greatest homology with the sequence of the Paenibacillus macerans endo-l,3-l,4-β-glucanase (82 and 88%, respectively). A fragment of the gene encoding the mature protein was expressed in Pichia pastoris. Purified recombinant enzyme Bgl26 was active towards barley β-glucan. The optimal pH for the enzyme to work was 7,0, and the optimum temperature range was 40-45 °C. The specific activity of β-glucanase was at the level of 6650 U/mg of protein, Km and Vmax were equal to 6.4 ± 0.3 mg/mL and 9450.1 ± 471.2 umol/(min-mg), respectively. The recombinant protein Bgl26 was characterized by high pH and thermal stability, as well as resistance to digestive enzymes. It is also shown that Co2+ ions have a positive effect on the activity of the enzyme. β-glucanase, β-glucan, Paenibacillus jamilae, Pichia pastoris The work was financially supported by the Ministry of Science and Higher Education of the Russian Federation (Unique Project Identifier RFMEFI60717X0179) and was carried out using the Multipurpose Scientific Installation of National Bio-Resource Center «All-Russian Collection of Industrial Microorganisms», NRC «Kurchatov Institute» - GOSNIIGENETIKA.

Gene Expression and Molecular Characterization of a Xylanase from Chicken Cecum Metagenome

A xylanase genexynAMG1with a 1,116-bp open reading frame, encoding an endo-β-1,4-xylanase, was cloned from a chicken cecum metagenome. The translatedXynAMG1protein consisted of 372 amino acids including a putative signal peptide of 23 amino acids. The calculated molecular mass of the matureXynAMG1was 40,013 Da, with a theoretical pI value of 5.76. The amino acid sequence ofXynAMG1showed 59% identity to endo-β-1,4-xylanase fromPrevotella bryantiiandPrevotella ruminicolaand 58% identity to that fromPrevotella copri.XynAMG1has two conserved motifs, DVVNE and TEXD, containing two active site glutamates and an invariant asparagine, characteristic of GH10 family xylanase. ThexynAMG1gene without signal peptide sequence was cloned and fused with thioredoxin protein (Trx.Tag) in pET-32a plasmid and overexpressed inEscherichia coliTuner™(DE3)pLysS. The purified matureXynAMG1was highly salt-tolerant and stable and displayed higher than 96% of its catalytic activity in the reaction containing 1 to 4 M NaCl. It was only slightly affected by common organic solvents added in aqueous solution to up to 5 M. This chicken cecum metagenome-derived xylanase has potential applications in animal feed additives and industrial enzymatic processes requiring exposure to high concentrations of salt and organic solvents.

The putative signal peptide of glucagon-like peptide-1 receptor is not required for receptor synthesis but promotes receptor expression

GLP-1R (glucagon-like peptide-1 receptor) mediates the ‘incretin effect’ and many other anti-diabetic actions of its cognate ligand, GLP-1 (glucagon-like peptide-1). It belongs to the class B family of GPCRs (G protein-coupled receptors) and possesses an N-terminal putative SP (signal peptide). It has been reported that this sequence is required for the synthesis of GLP-1R and is cleaved after receptor synthesis. In the present study, we conducted an in-depth exploration towards the role of the putative SP in GLP-1R synthesis. A mutant GLP-1R without this sequence was expressed in HEK293 cells (human embryonic kidney 293 cells) and displayed normal functionality with respect to ligand binding and activation of adenylate cyclase. Thus the putative SP does not seem to be required for receptor synthesis. Immunoblotting analysis shows that the amount of GLP-1R synthesized in HEK293 cells is low when the putative SP is absent. This indicates that the role of the sequence is to promote the expression of GLP-1R. Furthermore, epitopes tagged at the N-terminal of GLP-1R are detectable by immunofluorescence and immunoblotting in our experiments. In conclusion, the present study points to different roles of SP in GLP-1R expression which broadens our understanding of the functionality of this putative SP of GLP-1R and possibly other Class B GPCRs.

Computational identification, homology modelling and docking analysis of phytase protein from Fusarium oxysporum

The extracellular phytase structural gene was isolated from phytopathogenic fungus Fusarium oxysporum using PCR amplification (GenBank accession number KC708486). The gene possesses an open reading frame of 1,514 bp and two coding regions 1–44 and 156–1458 with one intron (45–155). The phy gene from F. oxysporum (Fophy) encodes a putative phytase protein of F. oxysporum (FoPhy) of 448 amino acids, which includes a putative signal peptide (21 residues). The deduced amino acid sequence of FoPhy exhibits 98% sequence identity with Aspergillus niger and Aspergillus awamori phytases. The deduced protein sequence contains the consensus motifs (RHGXRXP and HD), eight conserved cysteine residues and ten conserved putative N-glycosylation sites, which are conserved among histidine acid phosphatases. Computed structural model of FoPhy was found to consist of mixed α/β motifs and probable loops. The predicted model resembles the structure of Aspergillus niger phytase (root mean square deviation 0.23 Å). Ramachandran plot analysis revealed that 95.0% portion of residues fall into the most favourable regions. The predicted three-dimensional structures of FoPhy on molecular docking with substrates like inositol hexaphosphate, inositol hexasulphate and N-acetyl D-glucosamine showed its interaction with conserved histidine and aspartic acid residues in the active site, as also known for other fungal phytases. This study provides a detailed identification and characterization of the phytase from F. oxysporum, which may be helpful in elucidation of its role in pathogenesis and other transcriptional and expression studies.