Before revision: The following table summarizes the structure of the nik operon: Gene Protein encoded Functional Role nikA ABC transporter Ni2+binding component binds Ni2+ in the periplasm and transfers it to the permease; may also play a role in chemotaxis away from toxic concentrations of nickel nikB & nikC ABC transporter permease components transport of Ni2++ across the inner membrane nikD & nikE ABC transporter ATP-binding components hydrolyzes ATP to provide energy for the transport process nikR transcriptional regulator of the nikABCDE operon downregulates expression of the nik operon in the presence of excess Ni2+ ions Regulation nikR Regulation Regulation of expression of the nikR gene is achieved by two promoters.
After revision: The following table summarizes the structure of the nik operon: Gene Protein encoded Functional Role nikA ABC transporter Ni2+binding component binds Ni2+ in the periplasm and transfers it to the permease; may also play a role in chemotaxis away from toxic concentrations of nickel nikB & nikC ABC transporter permease components transport of Ni2++ across the inner membrane nikD & nikE ABC transporter ATP-binding components hydrolyzes ATP to provide energy for the transport process nikR transcriptional regulator of the nikABCDE operon downregulates expression of the nik operon in the presence of excess Ni2+ ions Regulation nikRRegulation Regulation of expression of the nikR gene is achieved by two promoters.