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Effects of Pressure and pH on the Physical Stability of an I-Motif DNA Structure.
Lepper, Christopher P; Williams, Martin A K; Edwards, Patrick J B; Filichev, Vyacheslav V; Jameson, Geoffrey B.
Afiliación
  • Lepper CP; School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
  • Williams MAK; School of Fundamental Sciences The MacDiarmid Institute and the Riddet Institute, Massey University, Palmerston North, New Zealand.
  • Edwards PJB; School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
  • Filichev VV; School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
  • Jameson GB; School of Fundamental Sciences The MacDiarmid Institute and the Riddet Institute, Massey University, Palmerston North, New Zealand.
Chemphyschem ; 20(12): 1567-1571, 2019 Jun 17.
Article en En | MEDLINE | ID: mdl-31087509
The thermodynamic stability of a cytosine(C)-rich i-motif tract of DNA, which features pH-sensitive [C..H..C]+ moieties, has been studied as function of both pressure (0.1-200 MPa) and pH (3.7-6.2). Careful attention was paid to correcting citrate buffer pH for known variations that stem from changes in pressure. Once pH-corrected, (i) at pH >4.6 the i-motif becomes less stable as pressure is increased (KD decreases), giving a small negative volume change for dissociation (ΔD V°) of the i-motif - a conclusion opposite to that which would be drawn if the buffer pH was not corrected for the effects of pressure; (ii) the i-motif's melting temperature increases by more than 30 K between pH 6.5 and 4.5, the consequence of an enthalpy for dissociation (ΔD H°) of 77(3) and 90(3) kJ (mol H+ )-1 at 0.1 and 200 MPa, respectively; (iii) below pH 4.6 at 0.1 MPa (pH 4.3 at 200 MPa) the melting temperature decreases as a result of double protonation of cytosine pairs, and ΔD H° and ΔD V° change signs; and (iv) the combination of ΔD H° and ΔD V° lead to the melting temperature at pH 4.3 being 3 K higher at 200 MPa than at 0.1 MPa.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: ADN Idioma: En Revista: Chemphyschem Asunto de la revista: BIOFISICA / QUIMICA Año: 2019 Tipo del documento: Article País de afiliación: Nueva Zelanda Pais de publicación: Alemania
Texto completo
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Imprimir
XML
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: ADN Idioma: En Revista: Chemphyschem Asunto de la revista: BIOFISICA / QUIMICA Año: 2019 Tipo del documento: Article País de afiliación: Nueva Zelanda Pais de publicación: Alemania