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On the Helical Structure of Guanosine 5'-Monophosphate Formed at pH 5: Is It Left- or Right-Handed?

ABSTRACT: Early X-ray fiber diffraction studies have established that the spontaneous gel formation of guanosine 5'-monophosphate (5'-GMP) under slightly acidic conditions (e.g., pH 5) results from self-assembly of 5'-GMP into a helical structure in which hydrogen-bonded guanine bases form a continuous helix with 15 nucleotides per 4 turns. For more than five decades, the sense of this helix is believed to be left-handed. Using multinuclear solid-state NMR and IR spectroscopic methods, we have finally determined the long-missing structural details of this helix. First, we found that this 5'-GMP helix is right-handed containing exclusive C3'-endo sugar puckers. Second, we showed that the central channel of this helix is free of Na+ ions, which is in sharp contrast to the helix formed by 5'-GMP at pH 8 where the central channel is filled with Na+ ions.

SUBMITTER: Wu G

PROVIDER: S-EPMC5688352 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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On the Helical Structure of Guanosine 5'-Monophosphate Formed at pH 5: Is It Left- or Right-Handed?

Wu Gang G Kwan Irene C M ICM Yan Zhimin Z Huang Yining Y Ye Eric E

Journal of nucleic acids 20171102

Early X-ray fiber diffraction studies have established that the spontaneous gel formation of guanosine 5'-monophosphate (5'-GMP) under slightly acidic conditions (e.g., pH 5) results from self-assembly of 5'-GMP into a helical structure in which hydrogen-bonded guanine bases form a continuous helix with 15 nucleotides per 4 turns. For more than five decades, the sense of this helix is believed to be left-handed. Using multinuclear solid-state NMR and IR spectroscopic methods, we have finally det ...[more]

PMID: 29230324

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