Nuclear Magnetic Resonance Structure and Mutational Analysis of the Lactococcin A Immunity Protein.
The class IId bacteriocin lactococcin A and the pediocin-like bacteriocins induce membrane leakage and cell death by specifically binding the mannose phophotransferase system (man-PTS) on their target cells. The bacteriocins' cognate immunity proteins that protect the producer cell from its own bacteriocin recognize and bind to the bacteriocin-man-PTS complex and thereby block membrane leakage. In this study, we have determined the three-dimensional structure of the lactococcin A immunity protein (LciA) by the use of nuclear magnetic resonance spectroscopy. LciA forms a four-helix bundle structure with a flexible C-terminal tail. Despite the low degree of sequence similarity between LciA and the pediocin-like immunity proteins, they share the same fold. However, there are certain differences between the structures. The C-terminal helix in LciA is considerably shorter than that observed in the pediocin-like immunity proteins, and the surface potentials of the immunity proteins differ. Truncated variants of LciA in which 6 or 10 of the C-terminal residues were removed yielded a reduced degree of protection, indicating that the unstructured C-terminal tail is important for the functionality of the immunity proteins.
Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo , P.O. Box 1066, Blindern, 0316 Oslo, Norway.
Per Eugen
PE
Kristiansen
Swedish NMR Centre, University of Gothenburg , P.O. Box 465, 405 30 Gothenburg, Sweden.
Cecilia
C
Persson
Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo , P.O. Box 1066, Blindern, 0316 Oslo, Norway.|Department of Biomedical and Biotechnological Sciences (BIOMETEC), Microbiology Section, University of Catania , via Androne 81, 95124 Catania, Italy.
Virginia
V
Fuochi
Swedish NMR Centre, University of Gothenburg , P.O. Box 465, 405 30 Gothenburg, Sweden.
Anders
A
Pedersen
Swedish NMR Centre, University of Gothenburg , P.O. Box 465, 405 30 Gothenburg, Sweden.
Göran B
GB
Karlsson
Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo , P.O. Box 1066, Blindern, 0316 Oslo, Norway.
Jon
J
Nissen-Meyer
Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo , P.O. Box 1066, Blindern, 0316 Oslo, Norway.
Camilla
C
Oppegård
D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004252:DNA Mutational Analysis / Q000379:methods*; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D009154:Mutation; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D000072417:Protein Domains; D017433:Protein Structure, Secondary
D001430:Bacteriocins; C069325:lactococcin A; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C037992:phosphoenolpyruvate-mannose phosphotransferase