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The Polypeptide Transport-associated (POTRA) Domains of TpsB Transporters Determine the System Specificity of Two-partner Secretion Systems   
Yazarlar
Sadeeq Ur Rahman
Jesus Arenas
Prof. Dr. Hülya ÖZTÜRK Prof. Dr. Hülya ÖZTÜRK
Kırşehir Ahi Evran Üniversitesi, Türkiye
Nicole Dekker
Peter van Ulsen
Özet
The two-partner secretion (TPS) systems of Gram-negative bacteria secrete large TpsA exoproteins by a dedicated TpsB transporter in the outer membrane. TpsBs contain an N-terminal module located in the periplasm that includes two polypeptide transport-associated (POTRA) domains. These are thought to initiate secretion of a TpsA by binding its N-terminal secretion signal, called the TPS domain. Neisseria meningitidis encodes up to five TpsA proteins that are secreted via only two TpsB transporters: TpsB1 and TpsB2. Of these two, the TpsB2 recognizes the TPS domains of all TpsAs, despite their sequence diversity. By contrast, the TpsB1 shows a limited recognition of a TPS domain that is shared by two TpsAs. The difference in substrate specificity of the TpsBs enabled us to investigate the role of the POTRA domains in the selection of TPS domains. We tested secretion of TPS domains or full-length TpsAs by TpsB mutants with deleted, duplicated, and exchanged POTRA domains. Exchanging the two POTRA domains of a TpsB resulted in a switch in specificity. Furthermore, exchanging a single POTRA domain showed that each of the two domains contributed to the cargo selection. Remarkably, the order of the POTRA domains could be reversed without affecting substrate selection, but this aberrant order did result in an alternatively processed secretion product. Our results suggest that secretion of a TpsA is initiated by engaging both POTRA domains of a TpsB transporter and that these select the cognate TpsAs for secretion.
Anahtar Kelimeler
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı JOURNAL OF BIOLOGICAL CHEMISTRY
Dergi ISSN 0021-9258
Dergi Grubu Q4
Makale Dili İngilizce
Basım Tarihi 07-2014
Cilt No 289
Sayı 28
Sayfalar 19799 / 19809
Doi Numarası 10.1074/jbc.M113.544627