title: The Crystal Structure of the YknZ Extracellular Domain of ABC Transporter YknWXYZ from Bacillus amyloliquefaciens.
abstract: Bacillus possesses the peptide toxin Sporulation-Delaying Protein (SDP), which can kill cells within a biofilm to support continued growth, thereby delaying the onset of biofilm sporulation. The four-component transporter YknWXYZ acts as a major SDP efflux pump to protect cells against the endogenous SDP toxin, for which YknYZ is a non-canonical ATP-binding cassette (ABC)-type transporter. YknYZ consists of the following two components: (1) an individual protein (YknY) and (2) a respective permease (YknZ). To date, the crystal structure, molecular function, and mechanism of action of the integral membrane protein YknZ remain to be elucidated. In this study, to characterize the structural and biochemical roles of YknZ in the functional assembly of YknWXYZ, we predicted and overexpressed the YknZ extracellular domain. We determined the crystal structure of B. amyloliquefaciens YknZ at a resolution of 2.0 Å. The structure revealed that the YknZ extracellular region exhibits significant structural similarity with the MacB periplasmic domain, which is a non-canonical ABC-type transporter in the tripartite macrolide-specific efflux pump in Gram-negative bacteria. We also found that the YknZ extracellular domain can directly bind to an extracellular component of YknX. This structural and biochemical study provides insights into the assembly of YknWXYZ, which may be relevant to understanding cannibalistic peptide toxin resistance in Bacillus and controlling bacterial growth.
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.|Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China.
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.
authors.forename: Jianyun
authors.initials: J
authors.lastname: Guo
authors.affiliation: School of Biological Engineering, Dalian Polytechnic University, Dalian 116034, Liaoning, China.
authors.forename: Lulu
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Life and Health Sciences, Northeastern University, Shenyang 110004, Liaoning, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Jin
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.
authors.forename: Shengdi
authors.initials: S
authors.lastname: Fan
authors.affiliation: Department of Bioengineering, College of Life Science, Dalian Nationalities University, Dalian 116600, Liaoning, China.
authors.forename: Chun-Shan
authors.initials: CS
authors.lastname: Quan
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Nam-Chul
authors.initials: NC
authors.lastname: Ha
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000069977:Bacillus amyloliquefaciens / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002942:Circular Dichroism; D003460:Crystallization / Q000379:methods; D011485:Protein Binding / Q000502:physiology; D000072417:Protein Domains / Q000502:physiology; D021122:Protein Subunits / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D021122:Protein Subunits