Characteristics in Molecular Vibrational Frequency Patterns between Agonists and Antagonists of Histamine Receptors

Oh, S. June Korea Genome Organization 2012 Genomics & informatics Vol.10 No.2

To learn the differences between the structure-activity relationship and molecular vibration-activity relationship in the ligand-receptor interaction of the histamine receptor, 47 ligands of the histamine receptor were analyzed by structural similarity and molecular vibrational frequency patterns. The radial tree that was produced by clustering analysis of molecular vibrational frequency patterns shows its potential for the functional classification of histamine receptor ligands.

Implications of the simple chemical structure of the odorant molecules interacting with the olfactory receptor 1A1

Oh, S. June Korea Genome Organization 2021 Genomics & informatics Vol.19 No.2

G protein–coupled receptors (GPCRs), including olfactory receptors, account for the largest group of genes in the human genome and occupy a very important position in signaling systems. Although olfactory receptors, which belong to the broader category of GPCRs, play an important role in monitoring the organism's surroundings, their actual three-dimensional structure has not yet been determined. Therefore, the specific details of the molecular interactions between the receptor and the ligand remain unclear. In this report, the interactions between human olfactory receptor 1A1 and its odorant molecules were simulated using computational methods, and we explored how the chemically simple odorant molecules activate the olfactory receptor.

ERRATUM : Figure Legend Correction

Oh, S. June Korea Genome Organization 2013 Genomics & informatics Vol.11 No.1

Computational evaluation of interactions between olfactory receptor OR2W1 and its ligands

Oh, S. June Korea Genome Organization 2021 Genomics & informatics Vol.19 No.1

Mammalian olfactory receptors are a family of G protein-coupled receptors (GPCRs) that occupy a large part of the genome. In human genes, olfactory receptors account for more than 40% of all GPCRs. Several types of GPCR structures have been identified, but there is no single olfactory receptor whose structure has been determined experimentally to date. The aim of this study was to model the interactions between an olfactory receptor and its ligands at the molecular level to provide hints on the binding modes between the OR2W1 olfactory receptor and its agonists and inverse agonists. The results demonstrated the modes of ligand binding in a three-dimensional model of OR2W1 and showed a statistically significant difference in binding affinity to the olfactory receptor between agonists and inverse agonists.

System-Wide Expression and Function of Olfactory Receptors in Mammals

Oh, S. June Korea Genome Organization 2018 Genomics & informatics Vol.16 No.1

Olfactory receptors (ORs) in mammals are generally considered to function as chemosensors in the olfactory organs of animals. They are membrane proteins that traverse the cytoplasmic membrane seven times and work generally by coupling to heterotrimeric G protein. The OR is a G protein-coupled receptor that binds the guanine nucleotide-binding $G{\alpha}_{olf}$ subunit and the $G{\beta}{\gamma}$ dimer to recognize a wide spectrum of organic compounds in accordance with its cognate ligand. Mammalian ORs were originally identified from the olfactory epithelium of rat. However, it has been recently reported that the expression of ORs is not limited to the olfactory organ. In recent decades, they have been found to be expressed in diverse organs or tissues and even tumors in mammals. In this review, the expression and expected function of olfactory receptors that exist throughout an organism's system are discussed.

Construction of phylogenetic trees by kernel-based comparative analysis of metabolic networks

Oh, S June,Joung, Je-Gun,Chang, Jeong-Ho,Zhang, Byoung-Tak BioMed Central 2006 BMC bioinformatics Vol.7 No.-

<P><B>Background</B></P><P>To infer the tree of life requires knowledge of the common characteristics of each species descended from a common ancestor as the measuring criteria and a method to calculate the distance between the resulting values of each measure. Conventional phylogenetic analysis based on genomic sequences provides information about the genetic relationships between different organisms. In contrast, comparative analysis of metabolic pathways in different organisms can yield insights into their functional relationships under different physiological conditions. However, evaluating the similarities or differences between metabolic networks is a computationally challenging problem, and systematic methods of doing this are desirable. Here we introduce a graph-kernel method for computing the similarity between metabolic networks in polynomial time, and use it to profile metabolic pathways and to construct phylogenetic trees.</P><P><B>Results</B></P><P>To compare the structures of metabolic networks in organisms, we adopted the exponential graph kernel, which is a kernel-based approach with a labeled graph that includes a label matrix and an adjacency matrix. To construct the phylogenetic trees, we used an unweighted pair-group method with arithmetic mean, i.e., a hierarchical clustering algorithm. We applied the kernel-based network profiling method in a comparative analysis of nine carbohydrate metabolic networks from 81 biological species encompassing Archaea, Eukaryota, and Eubacteria. The resulting phylogenetic hierarchies generally support the tripartite scheme of three domains rather than the two domains of prokaryotes and eukaryotes.</P><P><B>Conclusion</B></P><P>By combining the kernel machines with metabolic information, the method infers the context of biosphere development that covers physiological events required for adaptation by genetic reconstruction. The results show that one may obtain a global view of the tree of life by comparing the metabolic pathway structures using meta-level information rather than sequence information. This method may yield further information about biological evolution, such as the history of horizontal transfer of each gene, by studying the detailed structure of the phylogenetic tree constructed by the kernel-based method.</P>

Low Expression Profiles of Heat Stress-Related Genes in Capsicum annuum

( M. Ashrafuzzaman ),( S. June Oh ),( Choo Bong Hong ) 한국식물학회 2005 Journal of Plant Biology Vol.48 No.1

A cDNA library was constructed for hot pepper plants that had been heat-shock-treated. We used a modified differential screening method, double negative screening, to isolate 500 cDNA clones that represented genes with low expression levels under conditions of high-temperature stress. Of those 500 clones, 200 were randomly selected for single-read sequencing from the 5` ends. After annotation with Blasts, the sequence was applied to InterProScan to scan for functional motifs of proteins. Among the cDNA clones analyzed, about 41% of the ESTs could not be functionally classified. However, of those that could be, the largest portion of the ESTs (15%) were assigned to the category of cell res-cue and defense; genes involved in cell cycle/DNA processing constituted the smallest group, comprising 1% of the ESTs. Genes related to energy and protein fates constituted the second (10%) and third (9%) largest groups, respectively. Finally, 3% of the ESTs were assigned to transcription, and 2% to signal transduction. The high portion of unclassified ESTs probably resulted from the screening method, which was designed for low-expression messages. Likewise, the high number of ESTs for cell rescue and defense suggests that many genes with low levels of expression are associated with the stress response.

Deducing Isoform Abundance from Exon Junction Microarray

Kim Po-Ra,Oh S.-June,Lee Sang-Hyuk Korea Genome Organization 2006 Genomics & informatics Vol.4 No.1

Alternative splicing (AS) is an important mechanism of producing transcriptome diversity and microarray techniques are being used increasingly to monitor the splice variants. There exist three types of microarrays interrogating AS events-junction, exon, and tiling arrays. Junction probes have the advantage of monitoring the splice site directly. Johnson et al., performed a genome-wide survey of human alternative pre-mRNA splicing with exon junction microarrays (Science 302:2141-2144, 2003), which monitored splicing at every known exon-exon junctions for more than 10,000 multi-exon human genes in 52 tissues and cell lines. Here, we describe an algorithm to deduce the relative concentration of isoforms from the junction array data. Non-negative Matrix Factorization (NMF) is applied to obtain the transcript structure inferred from the expression data. Then we choose the transcript models consistent with the ECgene model of alternative splicing which is based on mRNA and EST alignment. The probe-transcript matrix is constructed using the NMF-consistent ECgene transcripts, and the isoform abundance is deduced from the non-negative least squares (NNLS) fitting of experimental data. Our method can be easily extended to other types of microarrays with exon or junction probes.

Molecular Vibration-Activity Relationship in the Agonism of Adenosine Receptors

Chee, Hyun Keun,Oh, S. June Korea Genome Organization 2013 Genomics & informatics Vol.11 No.4

The molecular vibration-activity relationship in the receptor-ligand interaction of adenosine receptors was investigated by structure similarity, molecular vibration, and hierarchical clustering in a dataset of 46 ligands of adenosine receptors. The resulting dendrogram was compared with those of another kind of fingerprint or descriptor. The dendrogram result produced by corralled intensity of molecular vibrational frequency outperformed four other analyses in the current study of adenosine receptor agonism and antagonism. The tree that was produced by clustering analysis of molecular vibration patterns showed its potential for the functional classification of adenosine receptor ligands.

Evolutionary Signature of Information Transfer Complexity in Cellular Membrane Proteomes

Kim, Jong-Min,Kim, Byung-Gee,Oh, S.-June Korea Genome Organization 2009 Genomics & informatics Vol.7 No.2

Cell membrane proteins play crucial roles in the cell's molecular interaction with its environment and within itself. They consist of membrane-bound proteins and many types of transmembrane (TM) proteins such as receptors, transporters, channel proteins, and enzymes. Membrane proteomes of cellular organisms reveal some characteristics in their global topological distribution according to their evolutionary positions, and show their own information transfer complexity. Predicted transmembrane segments (TMSs) in membrane proteomes with HMMTOP showed near power-law distribution and frequency characteristics in 6-TMS and 7-TMS proteins in prokaryotes and eukaryotes, respectively. This reaffirms the important roles of membrane receptors in cellular communication and biological evolutionary history.