si_0577 YbbK Putative stomatin/prohibitin-family membrane protease subunit YbbK si_0577 YbbK Putative activity regulator of membrane protease YbbK si_0577 YbbK Putative stomatin/prohibitin-family membrane protease subunit aq_911 si_0577 YbbK Putative membrane-bound ClpP-class protease associated with aq_911