The lactococcal abortive infection protein AbiP is membrane-anchored and binds nucleic acids
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- 作者：Susana Domingues ; Stephen McGovern ; Danuta Plochocka ; Má ; rio A. Santos ; S. Dusko Ehrlich ; Patrice Polard ; Marie-Christine Chopin
- 关键词：Bacteriophage ; Lactococcus lactis ; Abortive infection ; Membrane anchorage ; OB-fold ; Nucleic acid binding
- 刊名：Virology
- 出版年：2008
- 出版时间：30 March 2008
- 年：2008
- 卷：373
- 期：1
- 页码：14-24
- 全文大小：1005 K
文摘
AbiP, a lactococcal abortive phage infection system, has previously been shown to arrest phage bIL66M1 DNA replication around 10 min after infection and to inhibit the switch off of phage early transcripts. We report here the functional characterization and implication in the abortive infection phenotype of two domains identified in the AbiP sequence. We show that AbiP is a protein anchored to the membrane by an N-terminal membrane-spanning domain. Our results further suggest that membrane localization may be required for the anti-phage activity of AbiP. The remainder of the protein, which contains a putative nucleic acid binding domain, is shown to be located on the cytosolic side. Purified AbiP is shown to bind nucleic acids with an approximately 10-fold preference for RNA relative to ssDNA. AbiP interaction with both ssDNA and RNA molecules occurs in a sequence-independent manner. We have analyzed the effect of substitutions of aromatic and basic residues on the surface of the putative binding fold. In vitro and in vivo studies of these AbiP derivatives indicate that the previously reported effects on phage development might be dependent on the nucleic acid binding activity displayed by the membrane-bound protein.