Preferential location of bulged guanosine internal to a G x C tract by /sup 1/H NMR
A series of double-helical oligodeoxyribonucleotides of sequence corresponding to a frame-shift mutational hot spot in the lambda C/sub I/ gene, 5'-dGATGGGGCAG, are compared by proton magnetic resonance spectroscopy at 500 MHz of the exchangeable protons. Duplexes containing an extra guanine in a run of two, three, and four G x C base pairs are compared to regular helices of the same sequence and to another sequence containing an isolated bulged G, 5'-dGATGGGCAG x dCTGCGCCATC. The imino proton resonances are assigned by one-dimensional nuclear Overhauser effect spectroscopy. Resonances assigned to the G tract in bulge-containing duplexes are shifted anomalously upfield and are very broad. Imino proton lifetimes are determined by T/sub 1/ inversion-recovery experiments. The exchange rates of G-tract imino protons in bulged duplexes are rapid compared to those in regular helices and are discussed in terms of the apparent rate of solvent exchange for the isolated G bulge. Delocalization of a bulged guanosine in homopolymeric sequences can explain the observe changes in chemical shift and relaxation times across the entire G x C run, and the chemical shifts can be fit by a simple model of fast exchange between base-paired and unpaired states for the imino protons. This allows us to calculate the relative occupancies of each bulge site. In these sequences, the authors find the extra base prefers positions internal to the G tract over those at the edge.
- Research Organization:
- Yale Univ., New Haven, CT
- OSTI ID:
- 5444529
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:1; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structural model for an oligonucleotide containing a bulged guanosine by NMR and energy minimization
Base pair mismatches and carcinogen-modified bases in DNA: an NMR study of G x T and G x O/sup 4/meT pairing in dodecanucleotide duplexes
Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
AROMATICS
AZAARENES
AZINES
BARYONS
CYTOSINE
DNA
ELEMENTARY PARTICLES
FERMIONS
GUANINE
GUANOSINE
HADRONS
HEAVY WATER
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPIC EXCHANGE
MAGNETIC RESONANCE
MOLECULAR BIOLOGY
MUTATIONS
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
NUCLEONS
NUCLEOSIDES
NUCLEOTIDES
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OVERHAUSER EFFECT
OXYGEN COMPOUNDS
PROTONS
PURINES
PYRIMIDINES
RESONANCE
RIBOSIDES
WATER