ABC transport system

Eukaryotic ABC transport system Phosphotransferase system (PTS) Ion-coupled transport system Signal Transduction Two-component system Bacterial chemotaxis MAPK signaling pathway Second messenger signaling pathway Ligand-Receptor Interaction G-protein-coupled receptors Ion-channel-linked receptors Cytokine receptors Molecular Assembly Ribosome assembly Flagellar assembly Enzyme assembly... 

Finally, we propose that APR becomes phosphorylated by the putative APR-kinase April and thereby inactivated, as a second resistance mechanism in addition to the 16S rRNA methylation by KamB, during biosynthesis or thereafter. Because AprZ is significantly similar to the StrK protein, a member of the protein family of extracellular alkaline phosphates and a STR-phosphate-specific dephosphorylase (see Section 2.2.1.2), this modification is urgently suggested by presence of the conserved aprZ gene in the biosynthetic cluster. April is a member of the large kinase family comprising all the antibiotic and protein kinases. As in the STR producers, the postulated APR-phosphate would exported via the ABC transport system AprV/AprW and set free by dephosphorylation outside the cells via the phospatase AprZ. 

The periplasmic binding proteins function together with the other subunits of the ABC transporter system. One of the best understood systems is encoded by the histidine transport operon of Salmonella typhimurium,445 453 There are four genes his (encoding the histidine-binding protein), hisQ, hisM, and hisP. 

Figure 8-24 (A) MolScript ribbon drawing of the periplasmic histidine-binding protein HisJ, a component of an ABC transporter system of Salmonella. The bound L-histidine is shown as a ball-and-stick model. (B) Stereoscopic view of the histidinebinding site showing hydrogen-bonding interactions of protein side chains with the histidine. From Oh et al.i60 Courtesy of Giovanna Ferro-Luzzi Ames.

Sequence data of the HAS isoforms suggest that they contain seven membrane-associated regions and a central cytoplasmic domain possessing several consensus sequences that are substrates for phosphorylation by protein kinase c.181 182 The ABC transporter system proteins required for HA transport through the plasma membrane are encoded at a chromosomal region immediately adjacent to the HA synthase genes (P. Prehm, pers. commun.). 

A number of bacterial metal transporters belong to the family of ATP-binding cassette (ABC) transporter system (see Metallochaperones Metal Ion Homeostasis) These systems constitute one of the most abundant superfamilies of proteins. They are involved in the transport of a wide variety of substances and in many cellular processes. The zinc transporter ZnuA from E. Coli and Synechocystis sp. 6803, the proposed zinc transporter TroA from Treponema pallidum, and the proposed manganese transporter Streptococcus pneumoniae surface antigen, PsaA, are placed in cluster 9 of the ABC transporters. ... 

Transport systems for iron from siderophores, haem, or transferrin in Gram-positive bacteria, which lack an outer membrane, closely resemble the ABC transport systems found in the inner membrane of Gram-negative bacteria. Iron uptake involves a membrane-anchored binding protein, which resembles the PBP of Gram-negative organisms, and a membrane-associated ABC transporter (Fig. 7.9). 

Schneider, E. and Hunke, S. (1998) ATP-binding-cassette (ABC) transport systems frmctionaland structtual aspects of the ATP-hydrolyzing subtmits/ domains. FEMS Microbiology Reviews, 22 (1), 1-20. 

Interestingly, if organisms contain non-Bi2 cobalt enzymes such as nitrilases (Koba-yashi and Shimizu 1998), an additional slow, chemisosmotically driven uptake system (NiCoT protein family) is co-expressed with the enzyme (Komeda et al. 1997). ATP-hydrolyzing uptake systems for cobalt (e.g., ABC-transport systems) are not known. This indicates that cobalt for B12-enzymes may indeed be imported as cobalamin, Co(II) for other enzymes by NiCoT transport systems and that Co(II)-import by other systems may not be important in the natural environment of the cells. Co(II) is of medium toxicity and is detoxified by efflux systems (CDF protein family, RND-driven CBA-export systems) in bacteria and yeasts (Nies 2003). 

A number of bacterial metal transporters belong to the family of ATP-binding cassette (ABC) transporter system see Metallochaperones Metal Ion Homeostasi These... 

While class II non-lantibiotic bacteriocins appear to be secreted by the sec-independent universal ABC transporter system, it has recently been shown that some bacteriocins do not possess a double-glycine leader peptide but are, instead, synthesized with a typical W-terminal leader peptide of the sec-type. So far four such sec-dependent bacteriocins have been reported divergicin A [51], acidocin B (50], bacteriocin 31 [208] and enterocin P [209]. Recently, two bacteriocins, enterocin L50A and L50B, were found to be secreted without an N-terminal leader sequence or signal peptide [210]. 

They are usually synthesized as small precursor proteins or peptides that are processed with proteolytic elimination of their Af-terminal leader sequences, and the resultant mature peptides form one, two, or more putative amphipathic transmembrane a-helical spanners (TMSs). Many bacteriocins are encoded in operons that also encode an immunity protein and an ABC transport system (TC 3.A.l) with a protease domain at the Af-terminus. The ABC systems export the bacteriocins while the protease domains cleave the A-terminal leader sequence. A few bacteriocins are exported by the type II general secretory pathway rather than by ABC-type export systems. In some cases, expression of the bacteriocin-encoding operon is induced by a bacteriocin-like peptide which acts in conjunction with a two component sensor kinase-response regulator. 

Costantini, A., Vaudano, E., Rantsiou, K., et al. (2011) Quantitative expression analysis of mleP gene and two genes involved in the ABC transport system in Oenococcus oeni during rehydration. Appl Microbiol Biotechnol 91,... 

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