NMR resonance assignments of the lantibiotic immunity protein NisI from Lactococcuslactis

The lantibiotic nisin is a small antimicrobial peptide which acts against a wide range of Gram-positive bacteria. Nisin-producing Lactococcuslactis strains express four genes for self-protection against their own antimicrobial compound. This immunity system consists of the lipoprotein NisI and the ABC transporter NisFEG. NisI is attached to the outside of the cytoplasmic membrane via a covalently linked diacylglycerol anchor. Both the lipoprotein and the ABC transporter are needed for full immunity but the exact immunity mechanism is still unclear. To gain insights into the highly specific immunity mechanism of nisin producing strains on a structural level we present here the backbone resonance assignment of NisI (25.8 kDa) as well as the virtually complete 1H,15N,13C chemical shift assignments for the isolated 12.7 kDa N-terminal and 14.6 kDa C-terminal domains of NisI.