title: A tamB homolog is involved in maintenance of cell envelope integrity and stress resistance of Deinococcus radiodurans.
abstract: The translocation and assembly module (TAM) in bacteria consists of TamA and TamB that form a complex to control the transport and secretion of outer membrane proteins. Herein, we demonstrated that the DR_1462-DR_1461-DR_1460 gene loci on chromosome 1 of Deinococcus radiodurans, which lacks tamA homologs, is a tamB homolog (DR_146T) with two tamB motifs and a DUF490 motif. Mutation of DR_146T resulted in cell envelope peeling and a decrease in resistance to shear stress and osmotic pressure, as well as an increase in oxidative stress resistance, consistent with the phenotype of a surface layer (S-layer) protein SlpA (DR_2577) mutant, demonstrating the involvement of DR_146T in maintenance of cell envelope integrity. The 123 kDa SlpA was absent and only its fragments were present in the cell envelope of DR_146T mutant, suggesting that DR_146T might be involved in maintenance of the S-layer. A mutant lacking the DUF490 motif displayed only a slight alteration in phenotype compared with the wild type, suggesting DUF490 is less important than tamB motif for the function of DR_146T. These findings enhance our understanding of the properties of the multilayered envelope in extremophilic D. radiodurans, as well as the diversity and functions of TAMs in bacteria.
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Jiangliu
authors.initials: J
authors.lastname: Yu
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Shang
authors.initials: S
authors.lastname: Dai
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Weng
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Jiulong
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Qinghao
authors.initials: Q
authors.lastname: Li
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Hua
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002462:Cell Membrane / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D002473:Cell Wall / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D034301:Deinococcus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D009997:Osmotic Pressure; D018384:Oxidative Stress; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013312:Stress, Physiological
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins