The N-terminal hydrophobic segment of Streptomyces coelicolor FtsY forms a transmembrane structure to stabilize its membrane localization

• Published in: FEMS microbiology letters 2012-02, Vol.327 (2), p.164-171
• Main Authors: Shen, Xueling, Li, Shanzhen, Du, Yiling, Mao, Xuming, Li, Yongquan
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Binding; Biological and medical sciences; Cell Membrane - chemistry; Cell Membrane - genetics; Cell Membrane - metabolism; Coliforms; E coli; Escherichia coli; FtsY; Fundamental and applied biological sciences. Psychology; Hydrophobic and Hydrophilic Interactions; Hydrophobicity; Immunoblotting; Insertion; Integral membrane proteins; Localization; membrane localization; Membranes; Microbiology; Miscellaneous; N-Terminus; Protein Binding; Protein Structure, Tertiary; Protein Transport; Proteins; Receptors, Cytoplasmic and Nuclear - chemistry; Receptors, Cytoplasmic and Nuclear - genetics; Receptors, Cytoplasmic and Nuclear - metabolism; Signal recognition particle; Streptomyces coelicolor; Streptomyces coelicolor - chemistry; Streptomyces coelicolor - genetics; Streptomyces coelicolor - metabolism; transmembrane structure
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2011.02478.x

Abstract FtsY is the receptor of the signal recognition particle that mediates the targeting of integral membrane proteins in bacteria. It was shown that in Escherichia coli, the N-terminal region of FtsY contributes to its interaction with the membrane, but it is not inserted into the membrane. However, this study presents evidence that in Streptomyces coelicolor, FtsY has a hydrophobic region at its N-terminus, which forms a membrane insertion structure and contributes significantly to the binding between FtsY and membrane. Through membrane protein extraction followed by immunoblotting, we demonstrated that deletion of the N-terminal residues 11–39 from the S. coelicolor FtsY (ScFtsY) drastically reduced its membrane-binding capability and that the N-terminus of ScFtsY alone was capable of targeting the soluble EGFP protein onto the membrane with high efficiency. Furthermore, in a labeling experiment with the membrane-impermeable probe Mal-PEG, the ScFtsY N-terminal region was protected by the membrane and was not labeled. This observation indicates that this region was inserted into the membrane.