Jappelli R, Brenner S
Molecular Sciences Institute, La Jolla, CA 92037, USA.
J Mol Biol. 1996 Jun 21;259(4):575-8. doi: 10.1006/jmbi.1996.0340.
The lambda phage repressor is currently used as a genetic tool to analyze homodimeric interactions in Escherichia coli. We have applied this system to detect the interaction that takes place within an enzyme-protein inhibitor complex. The sequences encoding the catalytic subunit of the cAMP-dependent protein kinase and the active portion of the natural thermostable protein kinase inhibitor have been fused to the carboxy terminus of the repressor DNA binding domain and introduced into compatible plasmids. Co-expression of the two gene fusions in E. coli lead to the formation of heterodimers that confer a high level of protection from lambda phage infection. The level of lambda immunity depends specifically upon the amino acid sequence of the interacting proteins, as a single amino acid substitution in the inhibitor peptide (Phe10-Ala) restores the sensitivity phenotype.
λ噬菌体阻遏物目前被用作一种遗传工具，用于分析大肠杆菌中的同二聚体相互作用。我们已应用该系统来检测酶-蛋白抑制剂复合物内发生的相互作用。编码环磷酸腺苷（cAMP）依赖性蛋白激酶催化亚基和天然热稳定蛋白激酶抑制剂活性部分的序列已融合到阻遏物DNA结合结构域的羧基末端，并导入兼容的质粒中。这两种基因融合体在大肠杆菌中的共表达导致异二聚体的形成，从而赋予高水平的抵御λ噬菌体感染的能力。λ免疫水平具体取决于相互作用蛋白的氨基酸序列，因为抑制剂肽中的单个氨基酸取代（苯丙氨酸10-丙氨酸）可恢复敏感表型。
