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Müller, Kristin; Ca, Tidona; Bahr, Udo; Darai, Gholamreza

doi:10.1023/a:1008017820941

Cited by 42 publications

(41 citation statements)

References 65 publications

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“…A helix repeat of 10.5 bp has also been found in DNA looping by bacteriophage cI and E. coli LacI repressors in vitro (6,7). Dependence of loop formation on the relative angular orientation of the two protein binding sites in a periodic fashion and thereby estimation of the size of the helix repeat has also been studied in several systems in vivo including an artificial construct in which a heterologous promoter was spanned by gal operators, O E and O I (4,8,10,29,30). The size of a DNA helical turn by in vivo estimation was shown to be within 11.0 -11.3 bp.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Repression of the gal Promoters by GalR and HU Depends on the Proper Helical Phasing of the Two Operators

Lewis

Adhya

2002

Journal of Biological Chemistry

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Repression of transcription initiation from the two gal promoters, P1 and P2, requires binding of GalR protein to two flanking operators, O E and O I , binding of HU to a site, hbs, located between the two operators, and supercoiled DNA template. Previous experiments suggested that repression involves the interaction of two DNA-bound GalR proteins, which generates a 113-bp DNA loop encompassing the promoter region. Interaction between two DNA-bound proteins would be allowed if the binding sites on DNA are properly aligned. To test the idea that the observed repression of gal transcription in vitro is mediated by DNA looping, we investigated the effect of changing the relative angular orientation of O E and O I in the DNA helix. We found that repression is a periodic function of the distance between the two operator sites. Since repression recurred commensurate with DNA helical repeat, we conclude that the observed in vitro repression is mediated by DNA looping and the in vitro conditions reflect the in vivo situation.DNA looping appears to be a general phenomenon in DNA transaction reactions e.g. replication, transcription regulation, site-specific recombination, DNA condensation, etc. In gene regulation, DNA looping is frequently involved in both transcription repression and activation. Looping occurs when two identical or different proteins bound to spatially separated specific sites on DNA interact directly or through a mediator or when a bidentate protein simultaneously binds to distal DNA sites. Depending on the strength of the above interactions, DNA looping may or may not require the aid of a DNA bending protein (frequently referred to as an architectural protein), which facilitates loop formation by binding to a locus between the two distal DNA sites. In the loop, the two binding sites on DNA may be oriented in parallel or in antiparallel orientation (1-3).The feasibility and stability of such a DNA-multiprotein complex has been studied in several systems, including the gal, lac, and ara operons and bacteriophage of Escherichia coli. The complex formation depends on a variety of conditions: the proper angular orientation of the protein binding sites on DNA (4 -8), the size of the loop (9), and the superhelicity of the DNA (10 -12). Because shorter DNA resists torsional change (13), the proper angular orientation of the two binding sites is more important with relatively shorter loop size than with longer loop size. It has been suggested that a loop size of less than 150 bp strictly depends upon proper phasing of the protein binding sites, less so for 200 bp, and not at all for 400 bp and up. The precise size of the helix repeat also depends to a certain extent on the DNA sequence of the loop (9). Here we report the results of the effect of changing the relative angular orientation of the binding sites, which were separated by less than 150 bp in DNA, on transcription repression in the gal operon of E. coli (14). Previous results suggested that repression involves the formation of a DNA loop by the intera...

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Section: Discussionmentioning

confidence: 99%

In Vitro Repression of the gal Promoters by GalR and HU Depends on the Proper Helical Phasing of the Two Operators

Lewis

Adhya

2002

Journal of Biological Chemistry

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“…According to a 2009 in-depth policy analysis by Project Forum at the National Association of State Directors of Special Education (NASDE), there are predominantly four state approaches (used solely or in conjunction with another) that address the provision of SESPs for children identified for services under IDEIA. 105 The findings conclude that:…”

Section: Four Current State a Pproachesmentioning

confidence: 93%

“…113 Documentation reflecting such status must be kept at the LEA 114 for verification before appointing a SESP. 115 Furthermore, if the natural or adoptive parent is available, but does not attempt to act on behalf of the child for whatever reason, LEAs cannot automatically appoint a SESP. 116 In such a situation, a court order must curtail the parent's educational decision-making rights and clarify who should be making educational decisions for the child.…”

Section: B Preserving Educational Decision-making Rights Of Natural mentioning

confidence: 99%

Statewide Special Education Surrogate Parent Programs: Ensuring Quality Advocacy to All Foster Children With Special Education Needs

Choe

2012

Family Court Review

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The Individuals with Disabilities Education Improvement Act (IDEIA) protects foster children's rights to have a special education decision maker. For foster children who do not have a natural or adoptive parent or a responsible adult in their life to take on this role, IDEIA requires that a special education surrogate parent be appointed by appropriate procedures. Under IDEIA, these procedures are delegated to the states. Each state must ensure that local education agencies (LEAs) delineate methods for recruiting and maintaining a pool of available special education surrogate parents. Due to differing state laws and LEA procedures, there are many discrepancies in the quality and availability of special education surrogate parents. To combat these problems, this Note proposes principles for administrative regulations establishing statewide special education surrogate parent programs by examining existing statewide programs. Administered through a state's Department of Education in collaboration with child welfare agencies, statewide special education surrogate parent programs guarantee well‐qualified decision makers who will advocate for all children eligible for special education services.

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“…CE has become a powerful analytical microseparation technique in recent years that is especially suited for enantioseparations [14][15][16][17][18][19]. The CE enantioseparation of chloroquine has been achieved in the presence of various CDs as chiral selectors including sulfated b-CD [20][21][22], sulfobutylether-b-CD (SBE-b-CD) [23] or a mixtures of two g-CD derivatives, either hydroxypropyl-g-CD and carboxymethyl-g-CD or hydroxypropyl-g-CD and octakis(6-O-sulfo)-g-CD [24]. Furthermore, chloroquine enantioseparations in the presence of the polysaccharide colominic acid [25], human serum albumin [26], and arsenyl-L-(1)tartrate [27] have been published.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a capillary electrophoresis assay for the determination of the stereoisomeric purity of chloroquine enantiomers

Scriba

2011

Electrophoresis

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A stereoselective CE assay for the determination of the enantiomeric purity of (R)-(-)-chloroquine and (S)-(+)-chloroquine was developed and validated. The separations were performed in a 50.2/40 cm uncoated fused silica capillary at 20°C using a 100 mM sodium phosphate buffer, pH 2.5, containing 30 mg/mL sulfobutylether(VII)-β-cyclodextrin as background electrolyte operated at an applied voltage of -25 kV and 20°C. The detection wavelength was 225 nm. Carbamazepine was used as internal standard. The assay was validated in the range of 0.05-1.0% for the respective minor chloroquine enantiomer based on a concentration of 3 mg/mL of the major enantiomer, either (R)-(-)-chloroquine or (S)-(+)-chloroquine. The method was applied to analyze the stereoisomeric purity of synthetic samples of the chloroquine enantiomers.

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Untitled

Cited by 42 publications

References 65 publications

In Vitro Repression of the gal Promoters by GalR and HU Depends on the Proper Helical Phasing of the Two Operators

In Vitro Repression of the gal Promoters by GalR and HU Depends on the Proper Helical Phasing of the Two Operators

Statewide Special Education Surrogate Parent Programs: Ensuring Quality Advocacy to All Foster Children With Special Education Needs

Development and validation of a capillary electrophoresis assay for the determination of the stereoisomeric purity of chloroquine enantiomers

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