• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.212-217
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• 2011

${\alpha}$ and ${\beta}$-subunits (ApCpnA and ApCpnB) are group II chaperonins from the hyperthermophilic archaeum Aeropyrum pernix K1, specialized in preventing the aggregation and inactivation of substrate proteins under conditions of transient heat stress. In the present study, the cooperativity of ${\alpha}$- and ${\beta}$-subunits from the A. pernix K1 was investigated. The ApCpnA and ApCpnB chaperonin genes were overexpressed in E. coli Rosetta and Codonplus (DE3), respectively. Each of the recombinant ${\alpha}$- and ${\beta}$-subunits was purified to 92% and 94% by using anionexchange chromatography. The cooperative activity between purified ${\alpha}$- and ${\beta}$-subunits was examined using citrate synthase (CS), alcohol dehydrogenase (ADH), and malate dehydrogenase (MDH) as substrate proteins. The addition of both ${\alpha}$- and ${\beta}$-subunits could effectively protect CS and ADH from thermal aggregation and inactivation at $43^{\circ}C$ and $50^{\circ}C$, respectively, and MDH from thermal inactivation at $80^{\circ}C$C and $85^{\circ}C$. Moreover, in the presence of ATP, the protective effects of ${\alpha}$- and ${\beta}$-subunits on CS from thermal aggregation and inactivation, and ADH from thermal aggregation, were more enhanced, whereas cooperation between chaperonins and ATP in protection activity on ADH and MDH (at $85^{\circ}C$) from thermal inactivation was not observed. Specifically, the presence of both ${\alpha}$- and ${\beta}$- subunits could effectively protect MDH from thermal inactivation at $80^{\circ}C$ in an ATP-dependent manner.

• Animal cells and systems
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• 제1권4호
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• pp.589-594
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• 1997

The neuronal voltage-sensitive calcium channels (VSCCs) are multisubunit complexes consisting of $\alpha_1,\;\alpha_2-\delta$ and $\beta$ subunits. Heterologous expression and biochemical studies have shown that the activity of VSCCs is regulated by their $\beta$ subunits in a $\beta$ subunit isoform-specific manner. To elucidate the $\beta$ subunit identity of the P/Q-type calcium channel encoded by an $\alpha_{1A}$ subunit, which is exclusively expressed in the Purkinje and granule cell of the cerebellum, we have examined the spatial and temporal expression patterns of $\beta$ subunits and compared them with those of $\alpha_{1A}$ subunit in the developing rat cerebellum. Reverse transcriptase- polymerase chain reaction (RT-PCR) and Northern blot analysis have shown that $\beta_4$ subunit mRNA was prominently expressed in the cerebellum and much more abundant than any other distinct $\beta$ subunits. RNase protection assay has further demonstrated that the expression of $\alpha_{1A}$ and $\beta_4$ subunits increased during cerebellar development, while the amount of $\beta_2$ and $\beta_3$ mRNAs did not significantly change. In addition, a $\beta_4$ transcript was present in cultured cerebellar granule cells, but not in astrocyte cells, and the level of $\beta_4$ mRNA expression increased gradually in vitro seen as in vivo. Based on the spatial and temporal expression patterns of $\beta_4$ subunit, we conclude that $\beta_4$ may predominantly associate, but probably not exclusively, with the $\alpha_{1A}$ subunit in rat cerebellar granule cells.

• 대한약침학회지
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• 제19권2호
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• pp.163-166
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• 2016

Objectives: Quercetin is a flavonoid and an important dietary constituent of fruits and vegetables. In recent years, several pharmacological activities of quercetin, such as its neuroprotective activity and, more specifically, its anti-convulsant effects in animal models of epilepsy, have been reported. This study evaluated the role of quercetin pretreatment on gene expression of ${\gamma}$-amino butyric acid type A ($GABA_A$) receptor beta subunits in kainic acid (KA)-induced seizures in mice. Methods: The animals were divided into four groups: one saline group, one group in which seizures were induced by using KA (10 mg/kg) without quercetin pretreatment and two groups pretreated with quercetin (50 and 100 mg/kg) prior to seizures being induced by using KA. Next, the messenger ribonucleic acid (mRNA) levels of the $GABA_A$ receptor ${\beta}$ subunits in the hippocampus of each animal were assessed at 2 hours and 7 days after KA administration. Quantitative real-time polymerase chain reaction (RT-PCR) assay was used to detect mRNA content in hippocampal tissues. Results: Pretreatments with quercetin at doses of 50 and 100 mg/kg prevented significant increases in the mRNA levels of the ${\beta}_1$ and the ${\beta}_3$ subunits of the $GABA_A$ receptor at 2 hours after KA injection. Pretreatment with quercetin (100 mg/kg) significantly inhibited ${\beta}_1$ and ${\beta}_3$ gene expression in the hippocampus at 7 days after KA injection. But, this inhibitory effect of quercetin at 50 mg/kg on the mRNA levels of the ${\beta}_3$ subunit of the $GABA_A$ receptor was not observed at 7 days after KA administration. Conclusion: These results suggest that quercetin (100 mg/kg) modulates the expression of the $GABA_A$ receptor ${\beta}_1$ and ${\beta}_3$ subunits in the KA model of epilepsy, most likely to prevent compensatory responses. This may be related to the narrow therapeutic dose range for the anticonvulsant activities of quercetin.

• Fisheries and Aquatic Sciences
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• 제2권2호
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• pp.176-181
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• 1999

The variations of gene expression and pituitary contents of GTH subunits during the ovarian development of masu salmon, Oncorhynchus masou, were investigated. The pituitary GTHs contents was measured by radioimmunoassays (RIAs) using purified GTH subunits and their antibodies. Pituitary contents of GTH $I\beta$ gradually increased from April through August, and reached the maximum in October. On the other hand, pituitary contents of GTH $II\beta$ remained low until August, but they rapidly increased in October. Total RNAs were prepared from pooled pituitaries and the GTH subunits mRNA in pituitaries was quantified by Northern blot hybridization using masu salmon cDNA probes for each GTH subunit. GTH $I\beta$ mRNA level increased with the progression of ovarian maturity. However, GTH $II\beta$ mRNA was detected only at a more advanced stage, and were extremly high at ovulation. A high levels for GTH a mRNA was detected only at ovulation stage. The synchronous increase in pituitary contents and mRNA levels suggested that ovarian maturity in masu salmon was regulated by both GTH I and GTH II.

• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.135-142
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• 2000

In order to clarify the role of gonadal sex steroids in the synthesis of gonadotropin (GTH) subunits in immature rainbow trout, we examined in vitro and in vivo effects of testosterone (T) on the pituitary mRNA levels of GTH I $\beta$, GTH II$\beta$ and a subunits by Northern blot analysis and on the pituitary content levels of GTH I$\beta$ and GTH II$\beta$by radioimmunoassay (RIA). The mRNA levels of the a subunit in T-treated fish were not changed more dramatically than those in control fish both in vivo and in vitro. Interestingly, the mRNA levels of GTH I$\beta$ in T-treated fish were shown to be slightly lower than those in the control fish under these experimental conditions, but no differences were observed in pituitary GTH I$\beta$ contents. In contrast, the mRNA levels and pituitary contents of GTH II$\beta$ subunit were strongly increased by T both in vivo and in vitro. These results demonstrate that the expressions of GTH I$\beta$ and II$\beta$ subunit genes in immatue rainbow trout pituitary are subjected to differential regulation by T.

• BMB Reports
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• 제35권3호
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• pp.348-351
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• 2002

AquI DNA methyltransferase, M.AquI, catalyses the transfer of a methyl group from S-adenosyl-L-methionine to the C5 position of the outermost deoxycytidine base in the DNA sequence 5'CYCGRG3'. M.AquI is encoded by two overlapping ORFs (termed $\alpha$ and $\beta$) instead of the single ORF that is customary for Class II methyltransferase genes. The structural organization of the M.AquI protein sequence is quite similar to that of other bacterial C5-DNA methyltransferases. Ten conserved motifs are also present in the correct order, but only on two polypeptides. We separately subcloned the genes that encode the $\alpha$ and $\beta$ subunits of M.AquI into expression vectors. The overexpressed His-fusion $\alpha$ and $\beta$ subunits of the enzyme were purified to homogeneity in a single step by Nickel-chelate affinity chromatography. The purified recombinant proteins were assayed for biological activity by an in vitro DNA tritium transfer assay. The $\alpha$ and $\beta$ subunits of M.AquI alone have no DNA methyltransferase activity, but when both subunits are included in the assay, an active enzyme that catalyses the transfer of the methyl group from S-adenosyl-L-methionine to DNA is reconstituted. We also showed that the $\beta$ subunit alone contains all of the information that is required to generate recognition of specific DNA duplexes in the absence of the $\alpha$ subunit.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.32-32
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• 2002

To understand the functional roles of the neuron-specific $\beta$-subunit of large-conductance calcium-activated potassium ($BK_{Ca}$) channel, we isolate the full-length complementary DNA of $\beta$4-subunit from rat brain library and investigated its effects on the function of $\alpha$-subunit (Slo). The deduced amino acid sequence of rat $\beta$4 (r$\beta$4), 210 amino acids in length, was closely related to those of $\beta$4 subunits in other mammalian species but showed only a limited sequence homology to the other $\beta$-subunits, $\beta$1 to $\beta$3.(omitted)d)

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.38-38
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• 2001

We cloned the cDNA encoding the neuron-specific $\beta$-subunit ($\beta$4) of large-conductance calcium-activated potassium channels from rat brain and determined the DNA sequences of the entire coding region (GenBank accession; AY028605). The deduced amino acid sequences of r$\beta$4, 210 amino acids in length, are closely related to the $BK_{Ca}$ $\beta$4 subunits of other species but show only limited sequence homology to other $\beta$-subunits, $\beta$1-$\beta$3.(omitted)d)

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.710-716
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• 2003

Gonadotropin (GTH) is a pituitary glycoprotein hormone that regulates gonadal development in vertebrates. In teleosts, two types of gonadotropins, GTH-I and GTH-II, are produced in the pituitary, and they comprised of common ${\alpha}$ and distinct ${\beta}$ subunits. In the present study, the cDNAs encoding GTH ${\alpha}\;and\;GTH-II{\beta}$ subunits were cloned and sequenced from flounder (Paralichthys olivaceus) pituitary cDNA library. The nucleotide sequence of the a subunit was 619 bp long, encoding 124 amino acids, and that of the $GTH-II{\beta}$ subunit was 538 bp long, encoding 145 amino acids. GTH subunits had well conserved cysteines, when aligned with other members of the glycoprotein family. The ${\beta}$ subunit of gonadotropin II ($GTH-II{\beta}$) had a different N-linked glycosylation site. RT-PCR analysis showed an increase of GTH II mRNA levels in association with gonadal development, and also showed that the mRNA expression of the ${\alpha}$ subunit was detected only in tissues from pituitary glands.

• 한국자원식물학회지
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• 제12권3호
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• pp.198-203
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• 1999

콩 저장 단백질의 대부분은 globulin이며, 이중 7S와 11S가 70% 이상을 차지한다. 따라서 콩 단백질의 조성개량을 위해서는 11S/7S비율 조정이 우선되는데, 본 연구에서는 전기영동(SDS-PAGE)법을 사용하여 콩 단백질 7S와 11S를 분리 확인하고, 이들 분획 단백질의 유전변이를 분석하였다. 국내 3개지역에서 재배된 콩 장려품종 6계통들의 평균 7S 함량은 38.9% 이었고 11S는 61.2%의 함량을 나타내었다. 분산분석 결과 품종간에 는 유의성이 있었지만 지역간에는 변이가 없었으며, 품종 x 지역의 상호작용은 고도의 유의성을 나타내었다. 유전력은 7S분획중의 $\beta$함량이 72.7%로 높게 나타났다. 공분산을 이용한 상관계수 추정에서는 유전상관이 표현형 상관 보다 다소 높게 나타났다. 따라서 7S와 11S의 분획간 함량을 조정함으로써 콩 단백질의 조성을 개량할 수 있으리라 판단된다.