Interaction of guanylic acid with the Mg(II), Ca(II), Sr(II), and Ba(II) ions in the crystalline solid and aqueous solution: Evidence for the ribose C2′-endo/anti and C3′-endo/anti conformational changes
✍ Scribed by Heidar-Ali Tajmir-Riahi
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1991
- Tongue
- English
- Weight
- 655 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
The interaction of guanosine-5'-monophosphoric acid ( H,-GMP ) with the alkaline earth metal ions has been studied in aqueous solution at neutral pH. The crystalline salts of the type Mg-GMP 5H20, Ca-GMP 6H20, Sr-GMP * 7H20, and Ba-GMP * 7H20 were isolated and characterized by Fourier transform ir, 'H-nmr and x-ray powder diffraction measurements. Two types of macrochelate complexes have been identified: ( a ) The direct metalbase and indirect metal-phosphate bindings (inner and outer sphere interaction) for the Mg( 11) , Ca (11) , and Sr (11) , ions; and ( b ) the indirect metal-base and direct metal-phosphate bindings (outer and inner sphere interaction) for the Ba( 11) ion. In aqueous solution, an equilibrium exists between the base-metal-H20 -* * PO, and base -* * H20-M-P03 interactions. The ribose moiety shows C3'-endo/anti conformation in the free acid; C2'endolanti in the Na2-GMP salt; C3'-endo/anti in the Mg( I I ) -, Ca( 11) -, and S r ( 11) -GMP salts; and C2'-endo/anti, in the Ba(I1)-GMP salt. 10, 19-30.