Research Open Volume 2 Issue 1
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Journal of Molecular Genetics Research Open Volume 2 Issue 1 Research Article Impact of MTNR1B and SENP3 Gene on Male Infertility: Prediction of 3D Structural Modeling of Protein and Drug Interaction during Spermatogenesis Aprajita, Aniket K, Meenakshi Tiwari and Ajit K Saxena* Molecular Human Genetics Laboratory, Department of Pathology/ Laboratory Medicine, All India Institute of Medical Sciences-Patna, Bihar, India *Corresponding author: Dr Ajit K Saxena, Ph.D Professor and Head, Department of Pathology/ Lab Medicine, All India Institute of Medical Sciences-Patna, Bihar, India; Tel: 917781012677; Email: [email protected] Received: April 23, 2019; Accepted: April 30, 2019; Published: May 23, 2019; Abstract Melatonin Receptor 1B (MTNR1B) and Sentrin-specific protease-3 (SENP3) gene mutation plays a significant role in the functioning of Sertoli cells (SCs) and to provide nourishment for the differentiating germ cell in testis. In the present study, next gene sequencing (NGS) of infertile male showing that the mutation in MTNR1B and SENP3 genes are associated to the male infertility. To the best of our knowledge the structure of our candidate genes (MTNR1B & SENP3) are not available in literature as well as in database. Therefore, molecular modelling technique in field of structural biology becomes relevant to predict functional aspects of the genes coded protein(s). Due to lack of knowledge of 3D structures it becomes difficult to understand the physiological function and binding specificities of the ligand molecules to the target site (protein). Swiss Model is one of the best workspace for integrated Web-based modelling expert system, help to understand the known protein sequence. Ramachandran plot was constructed for minimizing the energy or ligand binding active sites. Since, lactate synthesize by SCs provides nutritional support for proliferating germ cells in the testis. On the basis of a sequence alignment, a 3D model structure has been designed for the target protein using molecular docking technique. Present study predicts the structural model of MTNR1B and SNEP3 gene coded protein and analysed the possible interaction with Methotrexate (MTX) to ligand binding. During a comparative docking scores with respect to target protein and MTX showing a strong binding strength to active sites. Interestingly, these findings may elucidate the mechanism of gene regulation of SCs mediated protein in testis, and their impact on gene- protein and drug interaction during spermatogenesis. Hence, the present study significantly contributes in designing and optimizing therapeutic strategies againstinfertility. Keywords: MTNR1B and SENP3 Gene Mutation, Protein Modelling, Methotrexate, Infertility, Sertoli Cells, Swiss Model. Introduction in all mammals, influences various physiological activities suc h as neuroendocrine function, regulation of reproduction, sexual Human testis, spermatogenesis is an inherently complicated maturation, immune regulation, thermoregulation, aging and process that produces millions of mature germ cells named sperms, antioxidant activity [4–6]. SENP3 gene is predominantly expressed in and thereby crucial part of male fertility. Spermatogenesis depends the nucleus of Sertoli and Spermatocytes in mouse testis. SENP3 gene on the promiscuous cross-talk between Sertoli cells and developing protein also compromises tight junction in Sertoli cells at the cell-cell germ cells (spermatocytes) under the intensive role of a coordinated interface by destructing the permeability function with a concomitant regulatory network composing of endocrine, paracrine, and autocrine decline in trans-epithelial electrical resistance in primary Sertoli factors [1,2]. cells. Moreover, SENP3 knockdown disrupts F-actin architecture in In the present study, we have selected Melatonin Receptor 1B Sertoli cells through intervening different signalling pathways [2]. (MTNR1B) and Sentrin- specific protease-3 (SENP3) genes showing However, the post-translational modification of proteins by ubiquitin- mutation in male infertility after whole exome sequencing by using like modifier SUMO is an important mechanism of SNEP3 gene to Illumina Next Generation Sequencing (NGS). These mutations are regulate transcriptional events including DNA repair and other further confirmed by Ensembl database (http://asia.ensembl.org/ biological process. SENP3 gene to regulate Sertoli cell function such Homo_sapiens/Gene/Variation_Gene/) in human genome. These as to maintains the blood testicular barrier in somniferous tubules to genes are mapped on MTNR1B on chromosome - 11 and SENP3 on stimulate and create appropriate environment for spermatogenesis chromosome -17 as well, which play an important role in germ - cells [7–9]. Therefore, the study of MTNR1B and SNEP3 gene mutation proliferation during spermatogenesis and maintain male fertility. The become relevant to correlate with the reference functioning of “Sertoli mutation of MTNR1B has been associated in male infertile cases [1,3]. cell only syndrome” in the cases of male infertility with abnormal MTNR1B transcribed to Melatonin (N-acetyl-5-methoxytryptamine), karyotypes (XXY/XYY) due to non-disjunction event during meiosis a neuro-hormone that is mainly secreted from the pineal gland I of spermatogenesis in testis [10]. J Mol Genet, Volume 2(1): 1–8, 2019 Ajit K Saxena (2019) Impact of MTNR1B and SENP3 Gene on Male Infertility: Prediction of 3D Structural Modeling of Protein and Drug Interaction during Spermatogenesis The rationale behind this study to recognize the impact of gene - ii) Template Search: Identify evolutionarily related proteins with protein and drug interaction using 3D modelled structure to explore experimentally solved structures mapping corresponding residues the mechanism of infertility during spermatogenesis. The Molecular of target sequence and template structure search through BLAST Docking (MD) is to give a best way to prediction of the ligand- [14] and HHBlits has been performed against the SWISS-MODEL binding protein complex structure using computational methods template library. (https://swissmodel.expasy.org/templates/) [15]. and MD has been the most widely employed technique for structure iii) Template Selection: After nd2 step completion, a building of based drug discovery programme [11]. The main aim is to explore homology model is the availability of one or more identical structure-based virtual knowledge for identification of “new” active template proteins whose structure has been elucidated rank by the compounds towards a particular target protein(s). Another important expected quality of the resulting models as estimated by Global aspect is the ability to handle ambiguous structure or conflicting Model Quality Estimate (GMQE), Quaternary Structure Quality information present in available structural data, which is crucial for Estimate (QSQE), and target–template sequence identity that the development of stable molecule and fully automated pipelines. selected template structure experimentally confirmed by x-ray Finally, we introduced an improved modeling engine and process crystallography or NMR with good resolution value [16,17]. increased the precision of model quality estimation and helpful in iv) Build Model: A 3D protein model is automatically generated drug designing. However, molecular docking combined with other for each selected template by first transferring conserves atom computational techniques and experimental data may be involved in coordinates as defined by the target template alignment [18]. analyzing drug metabolism to obtain significant information for drug v) Evaluate Build Model: Evaluating the quality of the resulting development program and extending the scope of ongoing project model by SWISS- MODEL, it relies on the QMEAN scoring associated structural biology. The present study may also be helpful function to quantify modelling errors and provide estimates of to explore the additional knowledge what not yet existing in the expected model accuracy [19]. literature regulating gene-protein interaction during spermatogenesis in infertility. Selection of Ligand Molecule Materials and Methods Methotrexate is antagonist of folate and have anti neoplastic with immunosuppressant properties. It is an inhibitor of tetrahydrofolate The information of MTNR1B and SENP3 gene was collected from dehydrogenase and prevents the formation of tetrahydrofolate, whole genome sequence and search protein coded sequences from necessary for synthesis of thymidylate, an essential component of Biological database (https://www.ncbi.nlm.nih.gov/protein). The 3D DNA synthesis (https://www.drugbank.ca/drugs/DB00563). Its structure of protein has not been reported in literature as well as in chemical formula is C20H22N8O5 and their molecular weight is 454.45 structural database (https://www.rcsb.org/). as shown in figure-2. Homology Modeling Identification of the binding Site If experimentally determined structure is not available in Structure - based design begins with the identification of the structural database in that condition a homology modeling is the best target molecule of a potential ligand binding site. Ideally, the target way to generate 3D structure of protein on the basis of target- template site is a pocket with a variety of potential hydrogen bond donors and alignment search with help of Sequence Database (https://www.ncbi. acceptors, hydrophobic characteristics, and molecular surface sizes. nlm.nih.gov/protein/?term=mtnr1b or senp3), Protein Data Bank