Photo‐CIDNP study of the interaction between lac repressor headpiece and lac operator DNA

FEBS Letters

Kaptein, R.²  Stob, S.¹  Boelens, R.²  Scheek, R.M.¹ 

[1] Department of Physical Chemistry, University of Groningen, Nijenborgh 16, 9747 AG Groningen The Netherlands;Department of Organic Chemistry, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands

关键词: Lac repressor;    Lac headpiece;    Lac operator;    Lac headpiece-operator complex;    Photo-CIDNP;    1H-NMR;    HP51;    N-terminal 51 amino acids of lac repressor;    HP59;    N-terminal 59 amino acids of lac repressor;    FI;    N-3-carboxymethyl lumiflavin;    IPTG;    1-methylethyl 1-thio-β-D-galactopyranoside;    ONPF;    2-nitrophenyl-β-D-fucoside;    CIDNP;    chemically induced dynamic nuclear polarisation;    NMR;    nuclear magnetic resonance;    NOE;    nuclear Overhauser effect;   

DOI  :  10.1016/0014-5793(88)80553-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Lac repressor headpiece (HP) and intact lac repressor have been studied using the photo-CIDNP method. At neutral pH histidine 29, tyrosines 7, 12 and 17 and methionine 1 are polarised. His-29 polarisations are weaker and broader in HP59 than in HP51 indicating that the C-terminal octapeptide in HP59 adopts a conformation that allows an interaction with His-29. The photo-CIDNP spectra of intact lac repressor and HP51 are very similar, showing that the same residues are accessible to the photo-excited flavin. An equimolar mixture of HP51 and a 14 base pair lac operator fragment strongly suppresses the photo-CIDNP effect of tyrosines 7 and 17 and abolishes the His-29 polarisations. The results are compared with earlier photo-CIDNP measurements on a complex of headpiece with poly[d(AT)] and with a model derived from a 2D NMR study on a lac headpiece-operator complex.

【 授权许可】

Unknown