Okuda Ken-ichi, Aso Yuji, Nagao Jun-ichi, Shioya Kouki, Kanemasa Youhei, Nakayama Jiro, Sonomoto Kenji
Laboratory of Microbial Technology, Division of Microbial Science and Technology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
FEMS Microbiol Lett. 2005 Sep 1;250(1):19-25. doi: 10.1016/j.femsle.2005.06.039.
The immunity to a lantibiotic, nukacin ISK-1, is conferred by NukFEG (ABC transporter) and NukH (lantibiotic-binding protein) cooperatively. The present study identifies the functional domains of NukH. The topological analysis indicated that NukH possesses two external loops and three transmembrane helices. Deletion of N or C terminus of NukH did not affect the function. Amino acids substitutions in the respective loops abolished the function. Deletion of the third transmembrane helix resulted in loss of immunity but did not affect the binding activity. These findings suggested that the whole structure of NukH, except for N and C termini, is essential for its full immunity function, and that NukH inactivates nukacin ISK-1 after binding.
NukFEG（ABC转运蛋白）和NukH（羊毛硫抗生素结合蛋白）共同赋予对羊毛硫抗生素nukacin ISK-1的免疫性。本研究确定了NukH的功能结构域。拓扑分析表明，NukH具有两个外环和三个跨膜螺旋。删除NukH的N端或C端不影响其功能。各个环中的氨基酸替换使功能丧失。删除第三个跨膜螺旋导致免疫性丧失，但不影响结合活性。这些发现表明，除N端和C端外，NukH的整体结构对其完整的免疫功能至关重要，并且NukH在结合后使nukacin ISK-1失活。
