• 제목/요약/키워드: anti-sigma

검색결과 59건 처리시간 0.029초

Redox-Dependent Modulation of RsrA, an Anti-Sigma Factor Regulating Thioredoxin Operons in Streptomyces coelicolor

  • Bae, Jae-Bum;Park, Joo-Hong;Roe, Jung-Hye
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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    • pp.54-54
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    • 2002
  • $\sigma$$\^$R/ is a sigma factor responsible for inducing the thioredoxin system in response to oxidative stress in Streptomyces coelicolor. RsrA, an anti-sigma factor, specifically binds to $\sigma$$\^$R/ and inhibits $\sigma$$\^$R/-directed transcription under reducing conditions. Exposure to H$_2$O$_2$ or thiol-specific oxidant diamide dissociates $\sigma$$\^$R/-RsrA complex. The redox-dependent regulation of $\sigma$$\^$R/-RsrA binding has been reported to involve thiol-disulfide exchange in RsrA, which contains 7 cysteines in 105 amino acid residues.(omitted)

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배치와 형태에 관한 분자궤도론적 연구 (제15보). 에틸렌 디아민의 Through-Space 및 Through-Bond 상호작용 (MO Studies of Configuration and Conformation (XV). Through-Space and Through-Bond Interactions In Ethylene Diamine)

  • 이익춘;손창국;송창현
    • 대한화학회지
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    • 제26권2호
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    • pp.65-72
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    • 1982
  • 여러 형태의(n${\pi}$/m) 및 (n-${\sigma}^*$) 구조가 에너지에 미치는 구조적인 기여를 살펴보기 위하여 n-프로필아민, n-프로필아민 라디칼, trans-및 cis-에틸렌 디아민에 대한 STO-3G 수준의 계산을 수행하였다. 그 결과 (5${\pi}$/5)구조가 (4${\pi}$/4)구조는 각각 인력 및 반발의 비결합 상호작용을 나타내었으며 서로 부가관계를 가짐을 알았다. anti(n-${\sigma}^*$) 구조는 syn(n-${\sigma}^*$)구조보다 강한 hyperconjugation효과를 보이지만 anti(n-${\sigma}^*$)구조에서 강한 핵간 반발력을 가지기 때문에 결과적으로 불안정한 겉보기 효과를 나타내었다. 더우기 안정화${\pi}$ -비결합 (5${\pi}$/5)구조는 anti(${\pi}$-${\sigma}^*$)구조를, 불안정화 ${\pi}$-비결합(4${\pi}$/4)구조는 syn(n-${\sigma}^*$)구조를 수반하며 상호 보강적으로 작용함을 알았다. 또한 이러한 상호 보강성이 일반적인 성질임을 알았다. 끝으로 말단의 고립 전자쌍에 의한 through-bond 상호작용을 논의하였으며 이러한 상호작용으로 에너지 준위가 $n_+ = \frac{1}{\sqrt{2}}(n_1\;+\;n_2)$$n_-\;=\;\frac{1}{\sqrt{2}}(n_1\;-\;n_2)$로 갈라지는데 이때 고립 전자쌍의 간단한 overlap pattern으로 n_준위가 안정한 준위임을 알았다.

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A NOTE ON INDECOMPOSABLE 4-MANIFOLDS

  • Cho, Yong-Seung;Hong, Yoon-Hi
    • 대한수학회보
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    • 제42권4호
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    • pp.817-828
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    • 2005
  • In this note we show that there is an anti-symplectic involution $\sigma\;:\;X\;\to\;X$ on a simply-connected, closed, non-Kahler and symplectic 4-manifold X with a disjoint union of Riemann surfaces ${\amalg}^n_{i=1}{\Sigma}_i,\;n\;{\ge}\;2$ as a fixed point set. Also we show that its quotient X/$\sigma$ is homeomorphic to $\mathbb{CP}^2{\sharp}r\mathbb{CP}^2$ but not diffeomorphic to $\mathbb{CP}^2{\sharp}r\mathbb{CP}^2,\;r\;=\;b_2^-(X/{\sigma})$.

Mixed CT/DT Cascaded Sigma-Delta Modulator

  • Lee, Kye-Shin
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제9권4호
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    • pp.233-239
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    • 2009
  • A mixed CT/DT 2-1 cascaded ${\Sigma\Delta}M$ which includes a first stage CT ${\Sigma\Delta}M$ and a second stage mismatch insensitive two-channel time-interleaved DT ${\Sigma\Delta}M$ is proposed. With this approach, the advantages of both CT and DT ${\Sigma\Delta}Ms$ including high speed operation, inherent anti-aliasing filter, and good coefficient matching can be achieved. The two-channel time-interleaved ${\Sigma\Delta}M$ used in the second stage alleviates the speed constraints of the DT ${\Sigma\Delta}M$, whereas enables better matching between the analog and digital filter coefficients compared to CT ${\Sigma\Delta}Ms$.

SOME RESULTS ON ENDOMORPHISMS OF PRIME RING WHICH ARE $(\sigma,\tau)$-DERIVATION

  • Golbasi, Oznur;Aydin, Neset
    • East Asian mathematical journal
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    • 제18권2호
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    • pp.195-203
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    • 2002
  • Let R be a prime ring with characteristic not two and U is a nonzero left ideal of R which contains no nonzero nilpotent right ideal as a ring. For a $(\sigma,\tau)$-derivation d : R$\rightarrow$R, we prove the following results: (1) If d is an endomorphism on R then d=0. (2) If d is an anti-endomorphism on R then d=0. (3) If d(xy)=d(yx), for all x, y$\in$R then R is commutative. (4) If d is an homomorphism or anti-homomorphism on U then d=0.

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The Putative Sigma (YlaC) and Anti-Sigma Factors (YlaD) from Bacillus subtilis

  • Ryu, Han-Bong;Tsogbadrakh. M;Sa-Ouk kang
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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    • pp.51-51
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    • 2001
  • Two open reading frame designated as ylaC and ylaD in the Bacillus subtilis genomic sequencing project, were cloned using pRB374 vector which is shuttle vector in E. coli and B. subtilis. YlaC and YlaD have the sequence homology to SigX and SigW to YbbM, respectively, which are known to be ECF sigmaand anti-sigma factor, respectively.(omitted)

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Mechanism of Redox- and Metal-dependent Modulation of RsrA, an Anti-sigma Factor for Redox-dependent Regulation of Thioredoxin Operons in Streptomyces coelicolor

  • Bae, Jae-Bum;Park, Ju-Hong;Roe, Jung-Hye
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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    • pp.63-63
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    • 2001
  • SigR ($\sigma$$\^$R/) is a sigma factor responsible for inducing the thioredoxin system in response to oxidative stress in Streptomyces coelicolor. RsrA specifically binds to $\sigma$$\^$R/ and inhibits $\sigma$$\^$R/-directed transcription under reducing conditions. Exposure to H$_2$O$_2$ or thiol-specific oxidant diamide dissociates $\sigma$$\^$R/-RsrA complex. RsrA contains 7 cysteine residues in 105 total amino acid residues.(omitted)

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A Quantitative Analysis of $\pi$-Nobonded and Through-Bond Interactions in n-Butane, n-Buthyl Radical and Tetramethylene Diradical$^1$

  • Lee Ikchoon;Cheun Young Gu
    • Bulletin of the Korean Chemical Society
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    • 제3권1호
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    • pp.1-4
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    • 1982
  • A quantitative treatment of ${\pi}$-nonbonded and $n-{\sigma}^{\ast}$ interactions and through-bond coupling effect was attempted using n-butane, n-butyl radical, and tetramethylene diradical. Results of STO-3G level calculations showed that: (1) conformational preferences can be predicted quantitatively based solely on the additive effect of ${\pi}$-nonbonded and $n-{\sigma}^{\ast}$ interactions, the predominant effect being the ${\pi}$-nonbonded interactions, (2) $(n-{\sigma}^{\ast})_{anti}$ is destabilizing whereas $(n-{\sigma}^{\ast})_{syn}$ is weakly stabilizing, which are contrary to what we expect from the normal $n-{\sigma}^{\ast}$ interaction, (3) througb-bond coupling of the two radical lobes is destabilizing for the triplet but stabilizing for the singlet tetramethylene diradical.