3.A.7.9.1
The Icm/Dot or Dot/Icm multicomponent protein secretion system. IcmS and IcmW form a complex that interacts with and may translocate substrate proteins (Ninio et al., 2005; De Buck et al., 2007; Cambronne and Roy, 2007). The crystal structure of the IcmR-IcmQ complex has been solved (Raychaudhury et al., 2009). Legionella pneumophila survives and replicates inside host cells by secreting ~300 effectors through the defective in organelle trafficking (Dot)/intracellular multiplication (Icm) type IVB secretion system (T4BSS). Ghosal et al. 2019, using electron cryotomography mapped the location of the core and accessory components of the Legionella core transmembrane subcomplex, revealing a well-ordered central channel that opens into a large, windowed secretion chamber with an unusual 13-fold symmetry. Immunofluorescence microscopy deciphered an early-stage assembly process that begins with the targeting of Dot/Icm components to the bacterial poles. Polar targeting of this T4BSS is mediated by two Dot/Icm proteins, DotU and IcmF, that are homologues of the T6SS membrane complex components TssL and TssM, suggesting that the Dot/Icm T4BSS is a hybrid system. Thus, the Dot/Icm complex assembles in an 'axial-to-peripheral' pattern (Ghosal et al. 2019).
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| Accession Number: | Q5ZYB6 |
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| Protein Name: | DotO aka IcmB |
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| Length: | 1009 |
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| Molecular Weight: | 112136.00 |
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| Species: | Legionella pneumophila subsp. pneumophila (strain Philadelphia 1 / ATCC 33152 / DSM 7513) [272624] |
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| Location1 / Topology2 / Orientation3: |
Cell membrane1 / Single-pass membrane protein2 |
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| Substrate |
protein polypeptide chain |
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1: MANWSESFFE GVDTFFAWLS TSLKQTTESY IDLETADSPT VLVNHDGSLL SVLKIEGITG
61: LAGPEEFERL VEGLANSFQA AMGRPGHALQ VYFSHDKQNI VKMIKDIYDP AEATASRLEL
121: NLRDLFEERV NYLSQYCAEE RVYFVLYTRP FNLASDQLKA ANKAKMKMIK DTKAPPFKNT
181: QTIFAAVPEI RDTHDAYVRA ILNDLDALNV IAKLLEVHDA VHAIRMTGDP DYTADDWRAT
241: LPGDKIPVRE LNNFEGDPSD LLWPPLSRQV LPRDAEIIDL RTVRVGDKIY ASTYIDLFPK
301: DVRPFISLFS RILPSHVPWK ISFLLESEGL STIKLKGLLA AILSFSSAQN RLISDSVNLL
361: KYIQLNTDEA IVRLRVVATT WAPEGNIPLL RRRSSELVKA IEGWGSTDVS EICGDPFAGF
421: VSSMLATTLN SSAVASVAPL SDVISMLPIT RPASPWKTGA LLFRTPDGKP WPFQPGSTEQ
481: TTWIDLVYAR PGSGKSVLSN ALNLALCLSG GLMRLPRIAI IDIGPSSSGL ISLLKEALPA
541: SKRHLVAYHR LRMTPDYSIN PFDTQLGCRY PTALERSFLV NFMTLLTTPL GAAKPYDGMA
601: DLAGMVVDEL YKSMADEFNP TPYAPGIEEF IDGILEEIGF VRDAKSTWWE VTDALYSAGF
661: VHEAMLAQRY AMPLLADAAS ICRTPSIEDL YEKITAPTGE SLINAFSRMI SSAVREYPIL
721: SRVTSFDIGD ARVVSLDLDE VAKSGGDAAD RQTAVMYMLA RYVLARHYYL TEESLNNVPE
781: QYKEYHKQRV LEIREDHKRI VYDEFHRTAK SSAVREQVII DMREGRKWKV QISLLSQAVD
841: DFDPVMIDFA TAIYVMDAGP SQAVEKTSQI FGLSETAKIA LRTRVHGPRQ GGATFLAQFA
901: TKTGINVQLL TLTLGPVELW AFSTTAEDAT VRNLLYRHLG PSEARRLLAA LFPNGTVTKE
961: LEARLASMKQ KVGLIEDDER EGMINQLVND ILDAYSKDPN VKSLPAKVG