• Journal of Microbiology and Biotechnology
• /
• 제14권3호
• /
• pp.520-524
• /
• 2004

A protein that exhibited a high similarity to a major serine transporter of Escherichia coli, SdaC, was found in Haemophilus injluenzae Rd. Also, $Na^+$-stimulated serine transport activity was detected in the cells. The sdaC of H. injluenzae was cloned and the properties of the transporter were investigated. The activity of serine transport was stimulated by $Na^+$. Uptake of $Na^+$ elicited by L-serine influx into cells was also observed, which supports the idea that L-serine is transported by a mechanism of $Na^+$serine symport. No uptake of $H^+$ elicited by L-serine influx was detected. This result was not consistent with that obtained with the homologous protein, SdaC of E. coli, which uses $H^+$as a coupling cation. The serine transport via the SdaC of H. influenzae was not inhibited by other amino acids such as threonine or D-serine like the SdaC of E. coli. Thus, the SdaC of H. influenzae is a $Na^+$-dependent L-serine specific symporter and an unusual natural mutant. The $K_m$ and the $V_{max}$, value for the serine transport in the SdaC of H. influenzae were $7.6\mu$M and 22.9 nmol/min/mg protein, respectively.

• Journal of Microbiology
• /
• 제41권2호
• /
• pp.78-82
• /
• 2003

We identified two proteins in Haemophilus influenzae Rd that exhibited high similarity to two major serine transporters of Escherichia coli (SstT and SdaC). Then, we investigated serine transport in H. influenzae Rd and detected $Na^{+}$-stimulated L-serine transport activity. The optimum NaCl concentration for this stimulation was about 20 mM. The uptake of $Na^{+}$ by H. influenzae Rd was found to be elicited by L-serine influx, which supports the idea that L-serine is transported by a mechanism of $Na^{+}$/serine symport. No uptake of $H^{+}$ elicited by L-serine influx was detected. $Na^{+}$/serine symport activity was not inhibited by other amino acids such as L-threonine or D-serine. Two distinct Km values were obtained from the kinetic analysis of serine transport. Thus, two serine transport pathways may exist in H. influenzae Rd, and it appears that both systems are stimulated by $Na^{+}$.

• Journal of Microbiology
• /
• 제41권3호
• /
• pp.202-206
• /
• 2003

A protein, exhibiting a high similarity to the major serine transporter of Escherichia coli, SstT, was found in Haemophilus influenzae Rd. A Na$\^$＋/-stimulated serine transport activity was also detected in the cells. The gene (sstT) for the Na$\^$＋//serine symporter from the chromosome of H. influenzae was cloned, and the properties of the transporter investigated. The serine transport activity was stimulated by Na$\^$＋/. The uptake of Na$\^$＋/ was elicited by the addition of serine or threonine into the cells, supporting the idea that these amino acids are transported by a mechanism of Na$\^$＋//substrate symport. No uptake of H$\^$＋/ was elicited by the influx of serine. The serine transport via the SstT of H. influenzae was inhibited by excess threonine, which was used as another substrate. The $K_{m}$ and the $V_{max}$ values for the serine transport were 2.5 ${\mu}$M and 14 nmol/min/mg protein, respectively.

• 생명과학회지
• /
• 제28권3호
• /
• pp.351-356
• /
• 2018

L-세린 탈수화효소(LSD)는 L-serine을 피루브산과 암모니아로 전환하는 반응을 촉매하는 iron-sulfur 함유 효소이다. 세균성 아미노산 탈수화 효소 중에서, L-serine에 대한 이들 특정 효소만이 촉매 부위에서 iron-sulfur cluster를 이용하는 것으로 보고되고 있다. 또한, 세균성 LSD는 구조적 특성과 도메인의 배열에 따라 네 가지 유형으로 분류된다. 현재까지, 이 효소들은 소수의 균주로부터 얻어진 LSD 효소에 대해서만 연구되었지만, 다양한 세균성 LSD의 촉매 메커니즘을 이해하기 위해서는 더 많은 자세한 조사가 요구된다. 본 연구에서, Mycobacterium tuberculosis H37Rv로부터 유래된 유형 II LSD (MtLSD) 단백질을 효소 동력학적 방법을 이용하여 생화학적 및 촉매적 특성을 규명하기 위해 발현 및 정제되었다. MtLSD에 대한 L-serine의 포화 곡선은 알로스테릭 협동성(allosteric cooperativity)을 나타내는 전형적인 S자형(sigmoid)의 특성을 보였다. 이때의 $K_m$과 $k_{cat}$ 값은 각각 $59.35{\pm}1.23mM$과 $18.12{\pm}0.20s^{-1}$로 계산되었다. 또한, 고정된 L-serine 농도 하에서 D-serine의 농도 대비 초속도에 대한 그래프는 비선형 쌍곡선 감쇠 형태를 보였고, $k_{cat}$ 값의 변화 없이 $30.46{\pm}5.93mM$의 겉보기 $K_i$ 값으로 D-serine에 대한 경쟁적 억제(competitive inhibition)를 나타내었다. 이들 연구는 MtLSD의 촉매 특성 및 기질 특이성에 관한 통찰력 있는 생화학적 정보를 제공한다.

• Journal of Microbiology and Biotechnology
• /
• 제21권4호
• /
• pp.374-378
• /
• 2011

To find alternative genetic resources for D-serine dehydratase (E.C. 4.3.1.18, dsdA) mediating the deamination of D-serine into pyruvate, metagenomic libraries were screened. The chromosomal dsdA gene of a wild-type Escherichia coli W3110 strain was disrupted by inserting the tetracycline resistance gene (tet), using double-crossover, for use as a screening host. The W3110 dsdA::tet strain was not able to grow in a medium containing D-serine as a sole carbon source, whereas wild-type W3110 and the complement W3110 dsdA::tet strain containing a dsdA-expression plasmid were able to grow. After introducing metagenome libraries into the screening host, a strain containing a 40-kb DNA fragment obtained from the metagenomic souce derived from a compost was selected based on its capability to grow on the agar plate containing D-serine as a sole carbon source. For identification of the genetic resource responsible for the D-serine degrading capability, transposon-${\mu}$ was randomly inserted into the 40-kb metagenome. Two strains that had lost their D-serine degrading ability were negatively selected, and the two 6-kb contigs responsible for the D-serine degrading capability were sequenced and deposited (GenBank code: HQ829474.1 and HQ829475.1). Therefore, new alternative genetic resources for D-serine dehydratase was found from the metagenomic resource, and the corresponding ORFs are discussed.

• The Korean Journal of Physiology and Pharmacology
• /
• 제13권3호
• /
• pp.161-168
• /
• 2009

In the peripheral nerves, injury-induced cytokines and growth factors perform critical functions in the activation of both the MEK/ERK and JAK/STAT3 pathways. In this study, we determined that nerve injury-induced ERK activation was temporally correlated with STAT3 phosphorylation at the serine 727 residue. In cultured Schwann cells, we noted that ERK activation is required for the serine phosphorylation of STAT3 by neuropoietic cytokine interleukin-6 (IL-6). Serine phosphorylated STAT3 by IL-6 was transported into Schwann cell nuclei, thereby indicating that ERK may regulate the transcriptional activity of STAT3 via the induction of serine phosphorylation of STAT3. Neuregulin-1 (NRG) also induced the serine phosphorylation of STAT3 in an ERK-dependent fashion. In contrast with the IL-6 response, serine phosphorylated STAT3 induced by NRG was not detected in the nucleus, thus indicating the non-nuclear function of serine phosphorylated STAT3 in response to NRG. Finally, we determined that the inhibition of ERK prevented injury-induced serine phosphorylation of STAT3 in an ex-vivo explants culture of the sciatic nerves. Collectively, the results of this study show that ERK may be an upstream kinase for the serine phosphorylation of STAT3 induced by multiple stimuli in Schwann cells after peripheral nerve injury.

• 대한환경공학회지
• /
• 제31권7호
• /
• pp.505-514
• /
• 2009

지구온난화 원인물질인 이산화탄소의 신규 흡수제로 serine 칼륨염을 제안하였고, serine 칼륨염의 이산화탄소 흡수특성을 monoethanolamine(MEA)의 결과와 비교하고 평가하였다. 비분산적외선 방식의 $CO_2$ 분석기를 장착한 스크리닝 장치와 흡수평형 측정장치를 이용하여 각 흡수제의 $CO_2$ 흡수/탈거 성능을 속도론적 양적으로 분석하였다. Serine 칼륨염의 유효 $CO_2$ 부하능은 0.425로써 MEA의 0.230보다 거의 두 배나 높았으며, cyclic capacity는 각각 0.354와 0.298로써 serine 칼륨염이 더 우수하였다. 한편 serine 칼륨염의 반응속도는 $CO_2$ 부하능이 0.1 이상에서 급격히 감소하여 MEA의 절반을 유지하였다. 흡수속도 증대를 위해 반응 촉진제로 plperazme과 tetraethylenepentamine을 흔합한 결과 각 경우 포화 $CO_2$ 부하능이 13.7%, 18.7% 증대되었다. Serine의 카르복실기에 서로 다른 종류의 금속을 치환하였을 때 ($Li^+,\;Na^+\;K^+$), serine 칼륨염의 $CO_2$ 흡수량이 나트륨염과 리튬염에 비해 각각 29.2%, 35.0% 높았다. 비슷한 기본구조를 가진 아미노산인 valine과 isoleucine 칼륨염의 흡수실험 결과, 벌키한 side group의 영향으로 인해 흡수속도가 serine 칼륨염에 비해 다소 느렸다. 반응 중 발생하는 침전과 이의 긍정적 이용 방법을 문헌에 근거하여 제안하였다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제19권6호
• /
• pp.543-547
• /
• 2015

We investigated the combined moisturizing effect of liposomal serine and a cosmeceutical base selected in this study. Serine is a major amino acid consisting of natural moisturizing factors and keratin, and the hydroxyl group of serine can actively interact with water molecules. Therefore, we hypothesized that serine efficiently delivered to the stratum corneum (SC) of the skin would enhance the moisturizing capability of the skin. We prepared four different cosmeceutical bases (hydrogel, oil-in-water (O/W) essence, O/W cream, and water-in-oil (W/O) cream); their moisturizing abilities were then assessed using a $Corneometer^{(R)}$. The hydrogel was selected as the optimum base for skin moisturization based on the area under the moisture content change-time curves (AUMCC) values used as a parameter for the water hold capacity of the skin. Liposomal serine prepared by a reverse-phase evaporation method was then incorporated in the hydrogel. The liposomal serine-incorporated hydrogel (serine level=1%) showed an approximately 1.62~1.77 times greater moisturizing effect on the skin than those of hydrogel, hydrogel with serine (1%), and hydrogel with blank liposome. However, the AUMCC values were not dependent on the level of serine in liposomal serine-loaded hydrogels. Together, the delivery of serine to the SC of the skin is a promising strategy for moisturizing the skin. This study is expected to be an important step in developing highly effective moisturizing cosmeceutical products.

• BMB Reports
• /
• 제31권3호
• /
• pp.303-306
• /
• 1998

Serine proteinase cDNA fragment from protozoan parasite Acanthamoeba culbertsoni was amplified by the reverse transcription-polymerase chain reaction (RTPCR) using degenerate oligonucleotide primers derived from conserved serine proteinase sequences. The amplified DNA fragment was subcloned and sequenced. The sequence analysis and alignment showed significant sequence similarity to other eukaryotic serine proteinases and conservation of the His, Asp, and Ser residues that form the catalytic triad. The cDNA fragment was cloned into the pGEMEX-1 expression vector and expressed in Escherichia coli. A resulting fusion protein of 56 kDa had proteolytic activity. The fusion protein reacted with sera of mice immunized with purified serine proteinase of A. culbertsoni in Western blot. Immune recognition of the fusion protein by mouse antisera suggested that the fusion protein may be valuable as a diagnostic reagent.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2002년도 생물공학의 동향 (X)
• /
• pp.205-207
• /
• 2002

효모 Pichia ciferrii 어 l 의해 생산되는 TAPS 는 쉽게 탈아세틸화 시킴으로 ceramide로 전환이 가능한 물질로 palmitoyl-CoA 와 아미노산인 L-serine으로부터 합성된다. 따라서 TAPS 생산에 영향을 줄 것으로 예측되는 serine과 serine 합성에 관련된 amino acid 들의 TAPS 생산에 대한 영향을 조사한 결과 cysteine 은 TAPS 생성에 방해를 주었으며 serine 은 TAPS 의 전구체임에도 불구하고 TAPS 농도의 향상을 기대할 수 없었다. 그러나 serine 의 전구체가 되는 glycine 의 첨가는 약 25% 의 TAPS 농도의 증가를 보여주었으며 특별히 glutamate 의 첨가는 20% 의 cell mass 의 증가와 37.7% 의 가장 많은 TAPS 의 증가를 보여주었다.