• 제목/요약/키워드: Homology

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3D Structure Prediction of Thromboxane A2 Receptor by Homology Modeling

  • Nagarajan, Santhosh Kumar;Madhavan, Thirumurthy
    • Journal of Integrative Natural Science
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    • v.8 no.1
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    • pp.75-79
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    • 2015
  • Thromboxane A2 receptors (TXA2-R) are the G protein coupled receptors localized on cell membranes and intracellular structures and play pathophysiological role in various thrombosis/hemostasis, modulation of the immune response, acute myocardial infarction, inflammatory lung disease, hypertension and nephrotic disease. TXA2 receptor antagonists have been evaluated as potential therapeutic agents for asthma, thrombosis and hypertension. The role of TXA2 in wide spectrum of diseases makes this as an important drug target. Hence in the present study, homology modeling of TXA2 receptor was performed using the crystal structure of squid rhodopsin and night blindness causing G90D rhodopsin. 20 models were generated using single and multiple templates based approaches and the best model was selected based on the validation result. We found that multiple template based approach have given better accuracy. The generated structures can be used in future for further binding site and docking analysis.

NMR Structural Analysis and 3D Homology Modelling of APG8a from Arabidopsis thaliana

  • Chae Young-Kee
    • Journal of the Korean Magnetic Resonance Society
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    • v.10 no.1
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    • pp.96-104
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    • 2006
  • The gene coding for APG8a (At4g21980), a protein from Arabidopsis thaliana, is involved in the autophagy process. The protein is an interesting candidate for structure determination by NMR spectroscopy. Toward this end, APG8a has been produced recombinantly in Escherichia coli and typical NMR experiments such as $^{15}N-HSQC$, HNCA, HN(CO)CA, CBCA(CO)NH, HCCH-TOCSY, HNCO were performed. The backbone resonances, HN, N, CA, CB, and C' were sequence-specifically assigned, and the secondary structures including 3 $\alpha$ helices and $4\beta$ strands were deduced based on the assignments. Due to the intrinsic flexibility or the effect of the denaturant, the backbone resonances were not fully observed. Since the structure calculation by NMR data was not possible, the 3-dimensional model was built based on the sequence homology, and compared with the NMR results. The overall structure of the model could explain and complement the NMR derived secondary structures.

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Amino Acid Sequence Homology of Hybrid Poplar O-methyltransferuse Involved in Lignin Biosynthesis

  • Park, Young-Goo;Sul, Ill-Whan;Shin, Dong-Ill;Park, Jang-Won;Park, Hee-Sung
    • Journal of Plant Biotechnology
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    • v.3 no.3
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    • pp.131-134
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    • 2001
  • In $\lambda$-Zap II vector system, a cDNA library was constructed for the developing secondary xylem mRNA from hybrid poplar, Populus nigra x maximowiczii. A cDNA clone of 1.5 kb in size, pOMTB1.4 encoding a lignin-bispecific O-methyltransferase was screened by plaque hybridization using a probe of 540 bp cDNA amplified by polymerase chain reaction from the cDNA library and identified by nucleotide sequencing. Its nucleotide sequence contains one open reading frame of 366 amino acids. The deduced amino acid sequence in comparison with that of Populus tremuloides showed the differences of 9 amino acids and revealed 85-99% homology among alfalfa, poplar and aspen.

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Theoretical Structure Prediction of Bradykinin Receptor B2 Using Comparative Modeling

  • Nagarajan, Santhosh Kumar;Madhavan, Thirumurthy
    • Journal of Integrative Natural Science
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    • v.9 no.4
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    • pp.234-240
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    • 2016
  • Bradykinin receptor B2, a GPCR protein, binds with the inflammatory mediator hormone bradkynin. It plays an important role in cross-talk between the renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS). Also, it is involved in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Hence, studuying the structural features of the receptor becomes important. But the unavailability of the three dimensional structure of the protein makes the analysis difficult. Hence we have performed the homology modelling of Bradykinin receptor B2 with 5 different templates. 25 different homology models were constructed. Two best models were selected based on the model validation. The developed models could be helpful in analysing the structural features of Bradykinin receptor B2 and in pathophysiology of various disorders related to them.

Hybrid Fungal Genome Annotation Pipeline Combining ab initio, Evidence-, and Homology-based gene model evaluation

  • Min, Byoungnam;Choi, In-Geol
    • 한국균학회소식:학술대회논문집
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    • 2018.05a
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    • pp.22-22
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    • 2018
  • Fungal genome sequencing and assembly have been trivial in these days. Genome analysis relies on high quality of gene prediction and annotation. Automatic fungal genome annotation pipeline is essential for handling genomic sequence data accumulated exponentially. However, building an automatic annotation procedure for fungal genomes is not an easy task. FunGAP (Fungal Genome Annotation Pipeline) is developed for precise and accurate prediction of gene models from any fungal genome assembly. To make high-quality gene models, this pipeline employs multiple gene prediction programs encompassing ab initio, evidence-, and homology-based evaluation. FunGAP aims to evaluate all predicted genes by filtering gene models. To make a successful filtering guide for removal of false-positive genes, we used a scoring function that seeks for a consensus by estimating each gene model based on homology to the known proteins or domains. FunGAP is freely available for non-commercial users at the GitHub site (https://github.com/CompSynBioLab-KoreaUniv/FunGAP).

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Three Dimensional Structure Prediction of Neuromedin U Receptor 1 Using Homology Modelling

  • Nagarajan, Santhosh Kumar;Madhavan, Thirumurthy
    • Journal of Integrative Natural Science
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    • v.10 no.1
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    • pp.7-13
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    • 2017
  • Neuromedin U receptor 1 is a GPCR protein which binds with the neuropeptide, neuromedin. It is involved in the regulation of feeding and energy homeostasis and related with immune mediated inflammatory diseases like asthma. It plays an important role in maintaining the biological clock and in the regulation of smooth muscle contraction in the gastrointestinal and genitourinary tract. Analysing the structural features of the receptor is crucial in studying the pathophysiology of the diseases related to the receptor important. As the three dimensional structure of the protein is not available, in this study, we have performed the homology modelling of the receptor using 5 different templates. The models were subjected to model validation and two models were selected as optimal. These models could be helpful in analysing the structural features of neuromedin U receptor 1 and their role in disorders related to them.

Homology Modelling of Chemerin like Receptor-1 (CMKLR1): Potential Target for Treating Type II Diabetes

  • B, Sathya.
    • Journal of Integrative Natural Science
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    • v.10 no.1
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    • pp.20-26
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    • 2017
  • Chemerin receptor, which predominantly expressed in immune cells as well as adipose tissue, was found to stimulate chemotaxis of dendritic cells and macrophages to the site of inflammation. Chemerin is a widely distributed multifunctional secreted protein implicated in immune cell migration, adipogenesis, osteoblastogenesis, angiogenesis, myogenesis, and glucose homeostasis. Recent studies suggest chemerin may play an important role in the pathogenesis of obesity and insulin resistance and it becomes a potential therapeutic target for treating type II diabetes. The crystal structure of chemerin receptor has not yet been resolved. Therefore, in the present study, homology modelling of CMKLR1 was done utilizing the crystal structure of human angiotension receptor in complex with inverse agonist olmesartan as the template. Since the template has low sequence identity, we have incorporated both threading and comparative modelling approach to generate the three dimensional structure. 3D models were generated and validated. The reported models can be used to characterize the critical amino acid residues in the binding site of CMKLR1.

Analysis of the Structure-stability Relationship of Cold-adapted Lipase PsLip1 from Homology Modeling

  • Choo, Dong-Won
    • Genomics & Informatics
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    • v.9 no.2
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    • pp.79-84
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    • 2011
  • Two initial models of cold-adapted lipase PsLip1 have been constructed, based on homology with the bacterial lipases Chromobacterium viscosum (CvLip) and Pseudomonas cepacia (PcLip), whose X-ray structures have been solved and refined to high resolution. The mature polypeptide chains of these lipases have 84% similarity. The models of Mod1 and Mod2 have been compared with the tertiary structures of CvLip and PcLip, respectively, and analyzed in terms of stabilizing interactions. Several structural aspects that are believed to contribute to protein stability have been compared: the number of conserved salt bridges, aromatic interactions, hydrogen bonds, helix capping, and disulfide bridges. The 3-dimensional structural model of PsLip1 has been constructed in order to elucidate the structural reasons for the decreased thermostability of the enzyme in comparison with its mesophilic counterparts.

Homology Modelling of Urotension-2 Receptor (UTS2R): Potential Target for Human Pharmacotherapy

  • B, Sathya.
    • Journal of Integrative Natural Science
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    • v.9 no.3
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    • pp.185-189
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    • 2016
  • Urotensin-2 receptor (UTS2R) is the most potent vasoconstrictor and plays a major role in the pathophysiology of various cardiovascular diseases and becomes a potential target for human pharmacotherapy. The crystal structure of Urotension-2 receptor has not yet been resolved. Hence, in the current study homology modelling of UTS2R was done utilizing the crystal structure of human delta opioid receptor as the template. Since the template has low sequence identity, we have incorporated both comparative modelling and threading approach to generate the three dimensional structure. 10 models were generated and validated. The reported models can be used to characterize the critical amino acid residues in the binding site of UTS2R.

Theoretical Protein Structure Prediction of Glucagon-like Peptide 2 Receptor Using Homology Modelling

  • Nagarajan, Santhosh Kumar;Madhavan, Thirumurthy
    • Journal of Integrative Natural Science
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    • v.10 no.3
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    • pp.119-124
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    • 2017
  • Glucagon-like peptide 2 receptor, a GPCR, binds with the glucagon-like peptide, GLP-2 and regulates various metabolic functions in the gastrointestinal tract. It plays an important role in the nutrient homeostasis related to nutrient assimilation by regulating mucosal epithelium. GLP-2 receptor affects the cellular response to external injury, by controlling the intestinal crypt cell proliferation. As they are therapeutically attractive towards diseases related with the gastrointestinal tract, it becomes essential to analyse their structural features to study the pathophysiology of the diseases. As the three dimensional structure of the protein is not available, in this study, we have performed the homology modelling of the receptor based on single- and multiple template modeling. The models were subjected to model validation and a reliable model based on the validation statistics was identified. The predicted model could be useful in studying the structural features of GLP-2 receptor and their role in various diseases related to them.