• Korean Journal of Biological Psychiatry
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• v.17 no.3
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• pp.119-126
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• 2010

Synaptic adhesion molecules mediate synapse formation, maturation and maintenance. These proteins are localized at synaptic sites in neuronal axons and dendrites. These proteins function as a bridge of synaptic cleft via interaction with another synaptic adhesion molecules in the opposite side. They can interact with scaffold proteins via intracellular domain and recruit many synaptic proteins, signaling proteins and synaptic vesicles. Scaffold proteins function as a platform in dendritic spines or axonal terminals. Recently, many genetic studies have revealed that synaptic adhesion molecules and scaffold proteins are important in neurodevelopmental disorders, psychotic disorders, mood disorders and anxiety disorders. In this review, fundamental mechanisms of synapse formation and maturation related with synaptic adhesion molecules and scaffold proteins are introduced and their psychiatric implications addressed.

• Journal of the Korean Magnetic Resonance Society
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• v.16 no.2
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• pp.103-110
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• 2012

Membrane proteins play a essential role in the biological systems and it is not easy to handle a membrane protein for its structural study. Solid-state NMR (ssNMR) can be a good tool to investigate the structures and dynamics of membrane proteins. In ssNMR, Magic Angle Spinning (MAS) and Cross Polarization (CP) can be utilized to reduce the line-broadening, leading to high resolution and sensitivity in the spectrum. ssNMR, if combined with other spectroscopic methods, can provide us a enough knowledge on structures and dynamics of membrane proteins in biological condition.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1377-1383
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• 2006

Among 46 Acinetobacter baumannii isolates collected in 2004, two imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Republic of Korea. Two carbapenemase-producing isolates were further investigated to determine the mechanism of resistance. These isolates were analyzed by antibiotic susceptibility testing, microbiological tests of carbapenemase activity, determination of pI, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. Two cases of infection by A. baumannii producing the IMP-1 ${\beta}$-lactamase were detected. The isolates were characterized by a modified cloverleaf synergy test and EDTA-disk synergy test. Isoelectric focusing of crude bacterial extracts revealed nitrocefin-positive bands with a pI value of 9.0. PCR amplification and characterization of the amplicons by direct sequencing indicated that the isolates carried a $bla_{IMP-l}$ determinant. The isolates were characterized by a multidrug resistance phenotype, including penicillins, extended-spectrum cephalosporins, carbapenems, and aminoglycosides. These results indicate that the observed imipenem resistance of two Korean A. baumannii isolates was due to the spread of an IMP-1-producing clone. Our microbiological test of carbapenemase activity is simple to screen class B metallo-${\beta}$-lactamase-producing clinical isolates to determine their clinical impact and to prevent further spread. This study shows that the $bla_{IMP-l}$ resistance determinant, which is emerging in Korea, may become an emerging therapeutic problem, since clinicians are advised not to use extended-spectrum cephalosporins, imipenem, and aminoglycosides. This observation emphasizes the importance of having effective control measures in Asian hospitals, such as early detection of colonized patients, isolation procedures, and a judicious use of antibiotics.

• Toxicological Research
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• v.30 no.1
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• pp.33-38
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• 2014

The human cytochrome P450 2J2 catalyzes an epoxygenase reaction to oxidize various fatty acids including arachidonic acid. In this study, three recombinant enzyme constructs of P450 2J2 were heterologously expressed in Escherichia coli and their P450 proteins were successfully purified using a $Ni^{2+}$-NTA affinity column. Deletion of 34 amino acid residues in N-terminus of P450 2J2 enzyme (2J2-D) produced the soluble enzyme located in the cytosolic fraction. The enzymatic analysis of this truncated protein indicated the typical spectral characteristics and functional properties of P450 2J2 enzyme. P450 2J2-D enzymes from soluble fraction catalyzed the oxidation reaction of terfenadine to the hydroxylated product. However, P450 2J2-D enzymes from membrane fraction did not support the P450 oxidation reaction although it displayed the characteristic CO-binding spectrum of P450. Our finding of these features in the N-terminal modified P450 2J2 enzyme could help understand the biological functions and the metabolic roles of P450 2J2 enzyme and make the crystallographic analysis of the P450 2J2 structure feasible for future studies.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.491-496
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• 2005

The biosynthetic gene cluster for the aminoglycoside antibiotic kasugamycin was isolated and characterized from the kasugamycin producing strain, Streptomyces kasugaensis KACC 20262. By screening a fosmid library using kasA, the gene encoding aminotransferase, we isolated a 22 kb DNA fragment. The fragment contained seventeen complete open reading frames (ORFs); one of these ORFs, kasD, was identified as the gene for dNDP-glucose 4,6-dehydratase, which catalyzes the conversion of dNDP-glucose to 4-keto-6-deoxy-dNDP-glucose. The enzyme showed a broad spectrum of substrate specificity. In addition, ksR was overexpressed in E. coli BL21 and proved to be a self-resistance gene against kasugamycin. These findings suggest that the isolated gene cluster is highly likely responsible for the biosynthesis of kasugamycin.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.20-36
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• 2001

The debate about whether depressive disorders should be divided into categories or arrayed along a continuum has gone for decade, without resolution. In our review, there is more evidence consistent with the spectrum concept than there is with the idea that depressive disorders constitute discrete clusters marked by relatively discontinuous boundaries. First, "depression spectrum", "is there a common genetic factors in bipolar and unipolar affective disorder", "threshold model of depression" and "bipolar spectrum disorder" are reviewed. And, a new subtype of depression is so called SeCA depression that is a stressor-precipitated, cortisol-induced, serotonin-related, anxiety/aggression-driven depression. SeCA depression is discussed. But, there is with the idea that depressive disorders constitute discrete subtypes marked by relatively discontinuous boundaries. This subtypes of depressive disorder were reviewed from a variety of theoretical frames of reference. The following issues are discussed ; Dexamethasone suppression test(DST), TRH stimulation test, MHPG, Temperament Character Inventory(TCI), and heart rate variability(HRV).

• Applied Biological Chemistry
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• v.46 no.4
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• pp.305-310
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• 2003

Hydrophobic core variant of ubiquitin appeared to have partially folded structure at pH around 2. The intrinsic tryptophan fluorescence emission maximum of this ubiquitin variant at pH 2 showed slight blue shift compare to that of unfolded state, suggesting that some residual tertiary structures remain in this solvent condition. At the same solvent condition, this ubiquitin variant binds with hydrophobic dye, 8-anilinonaphthalene-1-sulfonic acid(AMS), which is known to bind to exposed hydrophobic surface. Furthermore, far-UV circular dichroic spectrum of this ubiquitin variant in the diminished pH was remarkably different from the far-UV CD spectrum of the native state or unfolded state. Based on the molar ellipticity at 220 nm, this ubiquitin variant at pH 2 appeared to have significant amount of secondary structures. All these observations suggest that this ubiquitin variant in the diminished solvent pH has loosely folded hydrophobic core with some secondary structures, which are key features of molten globule conformation. Since molten globule has long been considered as a protein folding intermediate, it is considered that this hydrophobic core variant ubiquitin will serve as a valuable model to study protein folding process.

• Molecules and Cells
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• v.41 no.5
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• pp.486-494
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• 2018

Recently, we have reported that animals with telomerase reverse transcriptase (TERT) overexpression exhibit reduced social interaction, decreased preference for novel social interaction and poor nest-building behaviors-symptoms that mirror those observed in human autism spectrum disorders (ASD). Overexpression of TERT also alters the excitatory/inhibitory (E/I) ratio in the medial prefrontal cortex. However, the effects of TERT overexpression on hippocampal-dependent learning and synaptic efficacy have not been investigated. In the present study, we employed electrophysiological approaches in combination with behavioral analysis to examine hippocampal function of TERT transgenic (TERT-tg) mice and FVB controls. We found that TERT overexpression results in enhanced hippocampal excitation with no changes in inhibition and significantly impairs long-term synaptic plasticity. Interestingly, the expression levels of phosphorylated CREB and phosphorylated $CaMKII{\alpha}$ were significantly decreased while the expression level of $CaMKII{\alpha}$ was slightly increased in the hippocampus of TERT-overexpressing mice. Our observations highlight the importance of TERT in normal synaptic function and behavior and provide additional information on a novel animal model of ASD associated with TERT overexpression.

• Toxicological Research
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• v.26 no.3
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• pp.171-175
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• 2010

The human genome contains approximately 13 orphan cytochrome P450 (P450, CYP) genes, of which the apparent function or substrate has not been identified. However, they seem to possess their own biological relevance in some tissues or developmental stages. Here, we characterized the heterologously expressed CYP2W1, an orphan P450 enzyme. The recombinant CYP2W1 protein containing a $6{\times}$(His)-tag at Nterminus has been expressed in Escherichia coli and purified. Expression level of CYP2W1 holoenzyme was around 500 nmol P450 holoenzyme per liter culture medium. The reduced CO difference spectrum of CYP2W1 showed a maximum absorption at 449 nm. CYP2W1 indicated the significant induction to bioactivate Trp-P-1, MeIQ, and IQ in E. coli DJ701 tester strain. However, the bioactivation of B[$\alpha$]P, and NNK by CYP2W1 was relatively low. The model structure of CYP2W1 suggested the characteristic P450 folds with the lengths and orientations of the individual secondary elements. The F-G loop is situated on the distal side of heme to accommodate the flexibility of active site of CYP2W1. These studies can provide useful information for the finding of its biological roles and structure-function relationships of an orphan CYP2W1 enzyme.

• Anxiety and mood
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• v.6 no.2
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• pp.93-101
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• 2010

Research on obsessive-compulsive disorder (OCD) has advanced substantially since the DSM-IV was published in 1994. It is time to reexamine the nosology of this disorder, reviewing conflicting views regarding the classification as well as subtypes and specifiers of OCD. Although there is ongoing debate, OCD experts have suggested that OCD be retained in the section related to anxiety disorders and also that along with OCD, this section include obsessive-compulsive spectrum disorders (OCSD), a group of disorders closely related to OCD. A combined 'anxiety and obsessive-compulsive spectrum chapter' has also been proposed to include OCSDs. A growing body of scientific data has provided empirical support for the inclusion of a 'tic-related' subtype of OCD in the DSM-V. However, it remains controversial as to whether to introduce OCD symptom dimensions as specifiers as well as items in the diagnostic criteria. With regard to compulsive hoarding, there has been sufficient evidence to recommend that it be classified in the DSM-V as a separate disorder. Much work remains in order to ensure that the DSM-V is as evidence based as possible. It is necessary to strive toward integrating the biological and psychological data related to OCD and OCSD based on their endophenotypic features.