Characterization of a Novel Protein of the Animal Parasite, Toxoplasma Gondii - Case Study Example

CHARACTERIZATION OF A NOVEL PROTEIN OF THE ANIMAL PARASITE, TOXOPLASMA GONDII Name University Course Tutor Date Characterization of a novel protein of the animal parasite, Toxoplasma gondii Introduction Toxoplasma gondii refers to an obligate parasite (which is intracellular) and has the capability of posing substantial threat to the health of humans, in the form of toxoplasmosis (Zhou et al, 2011). It is worth noting that scientists are yet to find drugs for the chronic cyst stage of toxoplasmosis calling for the development of a vaccine capable of preventing the infection. Toxoplasma pellicle novel proteins play a significant role in the lifecycle of the parasite implying that their characterization has been given an immense deal of attention in the study of genetics. This is a report on the characterization of a novel protein of Toxoplasma gondii, which is an animal parasite (Zhou et al, 2011). The characterization of this protein has significantly relied on bioinformatics approaches-these approaches have aided scholars in the identification of an array of features of the gene TGME49_205320 thus leading to the characterization of the parasite’s novel proteins. Notably, the uncategorized genes of Toxoplasma gondii are great essence on the parasite’s cytoskeleton-beneath the plasma membrane (Wu et al, 2011). Notably, the cytoskeleton of the parasite plays a crucial role in the process of cell replication and invasion of the host; therefore, the development of developing new cures and treatments for toxoplasmosis call for adequate knowledge of the cytoskeleton. The ToxoDB database has been a significantly useful resource in the development of this report. Ideally, the exercise entailed the collection of information on the gene TGME49_205320 as listed in the database. This collection of information has been accompanied by experimental approaches with the capability of validating the data retrieved from the database. A systematic approach has been used in gaining full insight into the gene. This is inclusive of the determination of the presence of conserved gene order with other strains of Toxoplasma, alongside Neospora and Eimeria (Walle et al 2013). There is also examination of evidence of gene expression; this is achieved via the observation of mass/proteomic data. In this observation, it was worth noting the presence of such post-translational modification as phosphorylation, alongside observing the presence of regions of low complexity. It was also determined whether there were strong biases for reported amino acid residues by regions of low complexity. In addition, in order to gain full insight of the protein, it was a requirement to take note of the predicted protein’s molecular weight alongside other biophysical features. There was also the examination of gene expression evidence in transcriptome data (Andrade et al, 2010). The systematic procedure also entailed determination of the gene is conserved in various apicomplexan parasites alongside in a diversity of eukaryotes. The achievement of this task was subject to a review and analysis of blast results in order to look for matches in other organisms. The systematic procedure also entailed the determination of time of gene expression. This attempted to find out the information giving an insight into the gene expression pattern relative to the life cycle of the parasite cell. Results From the Toxo DB resource, it was found out that the gene has a protein length of 655; 4 exons; 0 TM, and no signal peptide, 4 exons; 0 TM, and no signal peptide (ToxoDB, 2015). It is located on chromosome TGME49_chrVIIa, with adjacent genes being as follows: TGME49_205340 (1468K-1470K), TGME49_205330(1470K-1472K), TGME49_2053201473K-1477K), TGME_205310(1478K-1480K), TGME_205300(1479K-1482K) (ToxoDB, 2015). From the resource, it also evident that there is the existence of conserved gene order for other Toxoplasma strains. From experiments listed on the resource, there is also evidence for expression of the gene, alongside evidence for post-translational modification. For instance, am experiment involving Tachyzoite phosphoproteome from infected cell of the host reveals a phosphorylation_site type of post-translational modification with residue S and 14 as the modification site (ToxoDB, 2015). Other experiments have also revealed the same type of post-translational modifications with modification sites being inclusive of 15, 16, 19, 20, 172, 196, and 200. Evidence for gene expression is also indicated by the presence of low complexity regions and their biases for the predicted amino acids residues. The gene was found to have a molecular weight of 70850 Da and iso-electric point of 4.85. A number of experiments listed in the resource also revealed Mass Spec-based Expression Evidence. For instance, the experiment Oocyst proteome (M4 TypeII) has 7 sequences and 11 spectra respectively (ToxoDB, 2015). On the other hand, the experiment Tachyzoite phosphoproteome - Calcium dependent (RH) has three sequences and three spectra. Discussion Parasites are capable of causing an immense deal of harm on human health with some kleading to diseases which cannot be cured at the chronic stage. Toxoplasmosis is an outstanding example with Toxoplasma gondii being the obligate parasite behind it. Ideally, this parasite is characteristic of four aspartic protease encoding genes; in the course of the characterization of novel proteins of Toxoplasma gondii, these encoding genes have been referred to as toxomepsin 1, 2, 3, and 5 (Kim, 2004). Bioinformatics approaches have been playing a key role in the course of analyzing and interpreting genomic and proteomic data. Bioinformatics have been making use of technologies and methods from statistics, mathematics, physics, computer science, medicine, and biology. Ideally, this has been identified as a powerful tool in the prediction of the function and structure from proteins originating from the sequence of its amino acids (Pszenny et al, 2012). This makes use of the principle of similarity with amino sequences that have already been categorized. This procedure has been playing a principal role in providing guidance for the genome experimental characterization. It is worth noting that bioinformatics has been of much use in the prediction of antigenic epitopes (with respect to proteins) owing to its low cost and effectiveness. Bioinformatics has led us to the realization that the gene TGME49_205320 encodes proteins (Donnelly et al, 2011). Through bioinformatics prediction, we have been able to establish the presence of conserved gene order with other apicomplexan genera and Toxoplasma strains. The approaches, based on bioinformatics, have also enabled us to establish the presence of low complexity regions thus evidence for post-translational modification. Ideally, these regions of low complexity are a reflection of particular amino acid’s repeated preponderance or motifs. In addition, the use of bioinformatics approaches has also enabled us determine a sense of biases for amino acids residues by the regions of low complexity in the gene TGME49_205320. Characterization of novel proteins of the parasite, Toxoplasma gondii has established that TgASP1 is a soluble transmembrane protein; using the bioinformatics approaches, we have been able to establish that this is a protein conserved between various Toxoplasma gondii strains (Donnelly et al, 2011). From the prediction results, it’s notable that there is absence of signal peptide sequence in the protein TgASP1 which ought to bring about an enhancement of anti-rTgASP antibodies’ secretion efficiency. Ideally, this protein has its location at the apical of the parasite according to the results of immunization experiments. However, analysis using bioinformatics approaches lead to the suggesting that this is a transmemberane proteins. Notably, the protein has no capability of localizing to parasite regions where such secretory organs as dense granules and rhoptries are located (Laliberté & Carruthers, 2011). As an obligate parasite, Toxoplasma gondii has its cytoskeleton as its main adaptation feature for replication alongside invasion of the animal host. Research studies have identified Toxoplasmosis as a chronic disease that ought to be preveneted via the use of an effective vaccine. The development of an effective vaccine for this infection, therefore, calls for adequate knowledge on the intron/exon structure, chromosome number, and adjacent genes with respect to the gene TGME49_205320 (Laliberté & Carruthers, 2011). In addition, the development of such a vaccine also calls for adequate knowledge on the post-translational modification and expression of the gene, the gene’s biophysical characteristics, and evidence on the Mass Spec-based Expression of the gene. Feature Description Intron/exon Structure The gene has a protein length of 655; 4 exons; 0 TM, and no signal peptide Chromosome number TGME49_chrVIIa Adjacent Genes TGME49_205340(1468K-1470K), TGME49_205330(1470K-1472K), TGME49_2053201473K-1477K), TGME_205310(1478K-1480K), TGME_205300(1479K-1482K) Table 1: Features of the gene (ToxoDB, 2015) Gene Strain TGGT1_205320 GT1 Tgme49_205320 ME49 TGVEG_205320 VEG Table 2: Conserved Gene Order for other Toxoplasma strains (ToxoDB, 2015) Gene Proteomics? TGGT1_205320 No Tgme49_205320 Yes TGVEG_205320 No Table 3: Evidence for Expression (ToxoDB, 2015) Translational Modification Yes Low Complexity Regions Yes Low Complexity Regions’ for Amino acids residues? Yes Table 4: Evidence of post-translational modification (ToxoDB, 2015) Molecular Weight 70850 Da Iso-electric Point 4.95 Table 5: Biophysical features of the gene (ToxoDB, 2015) Experiment Sequences Spectra Oocyst proteome (M4 TypeII) 7 11 Proteome During Infection in H. sapiens (ME49 VEG GT1 RH) 2 2 Tachyzoite membrane and cytosolic proteomes (RH) 1 1 Tachyzoite phosphoproteome - Calcium dependent (RH) 3 3 Tachyzoite phosphoproteome - Calcium dependent (RH) 3 3 Table 6: Mass Spec-based Expression Evidence (ToxoDB, 2015) References Andrade GM, Vasconcelos-Santos DV, Carellos EV, Romanelli RM, Vitor RW, Carneiro AC, & Januario JN 2010, Congenital toxoplasmosis from a chronically infected woman with reactivation of retinochoroiditis during pregnancy. J Pediatr (Rio J), 86(1):85–88. Review. Donnelly S, Dalton JP, Robinson MW 2011, How pathogen-derived cysteine proteases modulate host immune responses. Adv Exp Med Biol, 712:192–207. Kim K 2004, Role of proteases in host cell invasion by Toxoplasma gondii and other Apicomplexa. Acta Trop, 91(1):69–81. Laliberté J & Carruthers VB 2011, Toxoplasma gondii toxolysin4 is anextensively rocessed putative metalloproteinase secreted from micronemes. Mol Biochem Parasitol, 177(1):49–56. Pszenny V, Davis PH, Zhou XW, Hunter CA, Carruthers VB, & Roos DS 2012, Targeted disruption of Toxoplasma gondii serine protease inhibitor 1 increases bradyzoite cyst formation in vitro and parasite tissue burden in mice. Infect Immune, 80(3):1156–1165. ToxoDB 2015. TGME49_205320 [online]. Available at: < http://toxodb.org/toxo/showRecord.do?name=GeneRecordClasses.GeneRecordClass&source_id=TGME49_205320&project_id=ToxoDB#top> [Accessed 1 September 2015] Walle F, Kebede N, Tsegaye A, & Kassa T 2013, Seroprevalence and risk factors for Toxoplasmosis in HIV infected and non-infected individuals in Bahir Dar. Northwest Ethiopia. Parasit Vectors, 6(1):15. 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