Document Detail

Effect of initial ion positions on the interactions of monovalent and divalent ions with a DNA duplex as revealed with atomistic molecular dynamics simulations.
MedLine Citation:
PMID:  23153112     Owner:  NLM     Status:  Publisher    
Monovalent (Na(+)) and divalent (Mg(2+)) ion distributions around the Dickerson-Drew dodecamer were studied by atomistic molecular dynamics (MD) simulations with AMBER molecular modeling software. Different initial placements of ions were tried and the resulting effects on the ion distributions around DNA were investigated. For monovalent ions, results were found to be nearly independent of initial cation coordinates. However, Mg(2+) ions demonstrated a strong initial coordinate dependent behavior. While some divalent ions initially placed near the DNA formed essentially permanent direct coordination complexes with electronegative DNA atoms, Mg(2+) ions initially placed further away from the duplex formed a full, nonexchanging, octahedral first solvation shell. These fully solvated cations were still capable of binding with DNA with events lasting up to 20 ns, and in comparison were bound much longer than Na(+) ions. Force field parameters were also investigated with modest and little differences arising from ion (ions94 and ions08) and nucleic acid description (ff99, ff99bsc0, and ff10), respectively. Based on known Mg(2+) ion solvation structure, we conclude that in most cases Mg(2+) ions retain their first solvation shell, making only solvent-mediated contacts with DNA duplex. The proper way to simulate Mg(2+) ions around DNA duplex, therefore, should begin with ions placed in the bulk water.
Timothy J Robbins; Yongmei Wang
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-16
Journal Detail:
Title:  Journal of biomolecular structure & dynamics     Volume:  -     ISSN:  1538-0254     ISO Abbreviation:  J. Biomol. Struct. Dyn.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8404176     Medline TA:  J Biomol Struct Dyn     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
a Department of Chemistry , University of Memphis , Memphis , TN , 38152 , USA.
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