Structure of gene 5 protein-oligodeoxynucleotide complexes as determined by proton, 19F, and 31P nuclear magnetic resonance

作者：Joseph E. Coleman, Richard Allen Anderson, R. George Ratcliffe, Ian M. Armitage · 发表于：Biochemistry · 年份：1976 · DOI：10.1021/bi00670a001 · 被引用次数：72 · 研究领域：Enzyme Structure and Function、Protein Structure and Dynamics、RNA and protein synthesis mechanisms

1H nuclear magnetic resonance (NMR) spectra at 270 MHz of gene 5 protein from bacteriophage fd and its complexes with tetra- and octadeoxynucleotides show that approximately 12 of the 37 aromatic protons of the protein undergo upfield shifts upon nucleotide binding. In the complex with d(pT)8, the upfield shifts of the aromatic protons average approximately 0.3 ppm, while in the d(pA)8 complex the same resonances (assigned to tyrosyl protons) shift upfield approximately 0.8 ppm. These are interpreted as ring current shifts induced by stacking of the phenyl rings of three of the five tyrosyl residues with the bases of the nucleotides. 19FNMR of m-fluorotyrosyl gene 5 protein shows five separate resonances: two downfield from m-fluorotyrosine corresponding to "buried" tyrosyls and three near m-fluorotyrosine corresponding to "surface" tyrosyls. The latter (assigned to Tyr-26, -41, and -56, shown by chemical modification to be exposed to solvent) move upfield on nucleotide binding. The downfield 19F resonances are unaffected. Thus the aromatic protons shifted upfield on nucleotide binding appear to be those of Tyr-26, -41, and -56. In contrast to tetra-, octanucleotide binding to gene 5 protein induces large changes in the 1H resonances of the -CH3 groups of the Val, Leu, and Ile side chains. These may reflect conformational changes induced by protein-protein interactions between two monomers bound to the octanucleotide. 1H resonances of the epsilon-CH2 groups of the lysyl resid...