title: The archaic chaperone-usher pathways may depend on donor strand exchange for intersubunit interactions.
abstract: Subunit-subunit interactions of the classical and alternate chaperone-usher (CU) systems have been shown to proceed through a donor strand exchange (DSE) mechanism. However, it is not known whether DSE is required for intersubunit interactions in the archaic CU system. We have previously shown that the Myxococcus xanthus Mcu system, a member of the archaic CU family that functions in spore coat formation, is likely to use the principle of donor strand complementation to medicate chaperone-subunit interactions analogous to the classical CU pathway. Here we describe the results of studies on Mcu subunit-subunit interactions. We constructed a series of N-terminal-deleted, single amino acid-mutated and donor strand-complemented Mcu subunits, and characterized their abilities to participate in subunit-subunit interactions. It appears that certain residues in both the N and C termini of McuA, a subunit of the Mcu system, play a critical role in intersubunit interactions and these interactions may involve the general principle of DSE of the classical and alternate CU systems. In addition, the specificity of the M. xanthus CU system for Mcu subunits over other spore coat proteins is demonstrated.
authors.affiliation: Key Laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Wu
authors.affiliation: Key Laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China.
authors.forename: Shihui
authors.initials: S
authors.lastname: Xu
authors.affiliation: Key Laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Department of Biochemistry, Southeast University School of Medicine, Nanjing, Jiangsu 210009, PR China.|Key Laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Mao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism*; D016941:Myxococcus xanthus / Q000201:enzymology* / Q000235:genetics*; D017354:Point Mutation; D011485:Protein Binding; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013171:Spores, Bacterial
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D021122:Protein Subunits