INDICATIONS FOR A ROLE OF YIDD FOR NADHUBIQUINONE OXIDOREDUCTASE SUBUNIT K BIOGENESIS IN ESCHERICHIA COLI

• Main Author: Musnaini, Bibit
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/32329
• Institution: Institut Teknologi Bandung

In bacteria, most membrane proteins are inserted into the membrane by the Sec translocase. The Sec translocase can associate with another integral protein, called YidC, to insert some protein into the membrane, such as NuoK. YidC can also function as an independent insertase for a subset of small membrane proteins such as Foc, MscL and the coat proteins of the M13 and Pf3 phages. Upstream of the gene coding for YidC (yidC) is a gene encoding for the small protein YidD. YidD is thought to be involved in membrane insertion, but its exact function is presently unclear. To obtain more insight in the importance of YidD for cell viability, the effect of deletion of the yidD gene was analyzed. Deletion of yidD gene had no effect on aerobic cell growth, but caused slight growth defects under anaerobic conditions. YidD deletion resulted in reduced YidC levels when cells were grown under aerobic growth condition. In contrast, the YidC levels were increased when the YidD deletion strain was grown anaerobically. Since qPCR analysis could not detect significant changes in yidC transcription upon YidD deletion, these different YidC levels may be caused by changes in, for example, the stability of YidC. In vitro membrane insertion assay results suggest that YidD deletion decreased insertion of NuoK, a Sec/YidC-dependent integral membrane protein, and YidD overexpression increased insertion of NuoK.