Elucidation of spermidine interaction with nucleotide ATP by multiple NMR techniques

Zhiyan Song, Kari J. Parker, Idorenyin Enoh, Hua Zhao, Olarongbe Olubajo

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Interaction of polyamines with nucleotides plays a key role in many biological processes. Here we use multiple NMR techniques to characterize interaction of spermidine with adenosine 5-triphosphate (ATP). Two-dimensional1H-15 N spectra obtained from gs-HMBC experiments at varied pH show significant shift of N-1 peak around pH 2.0-7.0 range, suggesting that spermidine binds to N-1 site of ATP base. The binding facilitates N-1 deprotonation, shifting its pKa from 4.3 to 3.4. By correlating 15N and 31P chemical shift data, it is clear that spermidine is capable of concurrently binding to ATP base and phosphate sites around pH 4.0-7.0. The self-diffusion constants derived from1H PFG-diffusion measurements provide evidence that binding of spermidine to ATP is in 1:1 ratio, and pH variations do not induce significant nucleotide self-association in our samples. 31P spectral analysis suggests that at neutral pH, Mg2+ ion competes with spermidine and shows stronger binding to ATP phosphates. From 31P kinetic measurements of myosin-catalyzed ATP hydrolysis, it is found that binding of spermidine affects the stability and reactivity of ATP. These NMR results are important for advancing the studies on nucleotide-polyamine interaction and its impact on nucleotide structures and activities under varied conditions.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalMagnetic Resonance in Chemistry
Volume48
Issue number2
DOIs
StatePublished - Feb 2010
Externally publishedYes

Keywords

  • HMBC
  • Kinetic
  • NMR
  • Nucleotide
  • PFG-diffusion
  • Polyamine

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