ポリ（リボウリジル酸）とＭｎ｀２＋´の相互作用の核磁気緩和による研究

Abstract

T1s of protons of poly(ribouridylic acid) (poly(U)) were reduced by an addition of Mn2+. This phenomenon is considered to be caused by the dipole-dipole interaction between the proton and the electron spin of Mn2+. T1 minima were obtained from the temperature dependence of T1 of the complex, and the apparent distances between Mn2+ and the protons of poly(U) wer e estimated by substituting 1.59×10-9 s of which value is estimated from the relation that τc equals ωI-1. But if Mn2+ is assumed to bind to N(3), these estimated distances are longer than those which are estimated from Mn2+-proton distances presumed from the Dreiding model by the Bloembergen equation. The reason for this result is considered that a part of Mn2+ which binds to phosphate group chelates to N(3). It was found that O.28 of Mn2+binds to N(3) from the ratio of T1 estimated from the Dreiding model to T1 observed.τc of Mn2+-poly(U) complex at each temperature was eatimated from the: ratio of T1 at each temperature to T1 minimum. The comparison of these values with the τc of poly(U), which is obtained in the absence of Mn2+, indicates that the motion of poly(U) becomes slower in the presence of Mn2+ than in the absence of Mn2+.