sup 31 P NMR spectra of oligonucleotide duplex lac operator-repressor headpiece complexes: Importance of phosphate ester backbone flexibility in protein-DNA recognition

Journal Article · Mon Feb 17 23:00:00 EST 1992 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00121a038· OSTI ID:5488661

Karslake, C; Botuyan, M V; Gorenstein, D G ^[1]

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1. Purdue Univ., West Lafayette, IN (United States)

The {sup 31}P NMR spectra of various 14-base-pair lac operators bound to both wild-type and mutant lac repressor headpiece proteins were analyzed to provide information on the backbone conformation in the complexes. The {sup 31}P NMR spectrum of a wild-type symmetrical operator, d(TGTGAGCGCTCACA){sub 2}, bound to the N-terminal 56-residue headpiece fragment of a Y7I mutant repressor was nearly identical to the spectrum of the same operator bound to the wild-type repressor headpiece. In contrast, the {sup 31}P NMR spectrum of the mutant operator, d(TATGAGCGCTCATA){sub 2}, wild-type headpiece complex was significantly perturbed relative to the wild-type repressor-operator complex. The {sup 31}P chemical shifts of the phosphates of a second mutant operator, d(TGTGTGCGCACACA){sub 2}, showed small but specific changes upon complexation with either the wild-type or mutant headpiece. The {sup 31}P chemical shifts of the phosphates of a third mutant operator, d(TCTGAGCGCTCAGA){sub 2}, showed no perturbations upon addition of the wild-type headpiece. The {sup 31}P NMR results provide further evidence for predominant recognition of the 5{prime}-strand of the 5{prime}-TGTGA/3{prime}-ACACT binding site in a 2:1 protein to headpiece complex. It is proposed that specific, strong-binding operator-protein complexes retain the inherent phosphate ester conformational flexibility of the operator itself, whereas the phosphate esters are conformationally restricted in the weak-binding operator-protein complexes.

• OSTI ID: 5488661
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 31:6; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
CHEMICAL REACTIONS
CROSS-LINKING
DNA
ESTERS
GENE OPERONS
GENE REPRESSORS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
NUCLEOPROTEINS
ODD-EVEN NUCLEI
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHONIC ACID ESTERS
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
POLYMERIZATION
PROTEINS
RESONANCE
STABLE ISOTOPES