Casas-Finet J R, Khamis M I, Maki A H, Chase J W
FEBS Lett. 1987 Aug 17;220(2):347-52. doi: 10.1016/0014-5793(87)80844-x.
The binding of both wild-type and point-mutated E. coli single-stranded DNA-binding (SSB) protein to poly(deoxythymidylic acid) has been studied by fluorescence and optical detection of triplet state magnetic resonance spectroscopy. Involvement of tryptophan residues 40 and 54 in stacking interactions with nucleotide bases has been inferred earlier from such studies. Investigation of a point mutation in the E. coli SSB gene product obtained by site specific oligonucleotide mutagenesis in which Phe-60 is replaced by alanine strongly suggests the participation of Phe-60 in the binding process, possibly by the formation of an extended stacking structure by Trp-54, thymine and Phe-60. This hypothesis is supported by results on the point mutations in which His-55 is replaced by either leucine or tyrosine.
通过三重态磁共振光谱的荧光和光学检测，研究了野生型和点突变的大肠杆菌单链DNA结合（SSB）蛋白与聚（脱氧胸苷酸）的结合。此前从这类研究中推断，色氨酸残基40和54参与了与核苷酸碱基的堆积相互作用。对通过位点特异性寡核苷酸诱变获得的大肠杆菌SSB基因产物中的一个点突变进行研究，其中苯丙氨酸-60被丙氨酸取代，这强烈表明苯丙氨酸-60参与了结合过程，可能是通过色氨酸-54、胸腺嘧啶和苯丙氨酸-60形成延伸的堆积结构。这一假设得到了组氨酸-55被亮氨酸或酪氨酸取代的点突变结果的支持。
