ATP-Binding Cassette Systems of Brucella

Brucellosis is a prevalent zoonotic disease and is endemic in the Middle East, South America, and other areas of the world. In this study, complete inventories of putative functional ABC systems of five Brucella species have been compiled and compared. ABC systems of Brucella melitensis 16M, Brucella abortus 9-941, Brucella canis RM6/66, Brucella suis 1330, and Brucella ovis 63/290 were identified and aligned. High numbers of ABC systems, particularly nutrient importers, were found in all Brucella species. However, differences in the total numbers of ABC systems were identified (B. melitensis, 79; B. suis, 72; B. abortus 64; B. canis, 74; B. ovis, 59) as well as specific differences in the functional ABC systems of the Brucella species. Since B. ovis is not known to cause human brucellosis, functional ABC systems absent in the B. ovis genome may represent virulence factors in human brucellosis

ATP-binding cassette systems in Burkholderia pseudomallei and Burkholderia mallei

BACKGROUND: ATP binding cassette (ABC) systems are responsible for the import and export of a wide variety of molecules across cell membranes and comprise one of largest protein superfamilies found in prokarya, eukarya and archea. ABC systems play important roles in bacterial lifestyle, virulence and survival. In this study, an inventory of the ABC systems of Burkholderia pseudomallei strain K96243 and Burkholderia mallei strain ATCC 23344 has been compiled using bioinformatic techniques. RESULTS: The ABC systems in the genomes of B. pseudomallei and B. mallei have been reannotated and subsequently compared. Differences in the number and types of encoded ABC systems in belonging to these organisms have been identified. For example, ABC systems involved in iron acquisition appear to be correlated with differences in genome size and lifestyles between these two closely related organisms. CONCLUSION: The availability of complete inventories of the ABC systems in B. pseudomallei and B. mallei has enabled a more detailed comparison of the encoded proteins in this family. This has resulted in the identification of ABC systems which may play key roles in the different lifestyles and pathogenic properties of these two bacteria. This information has the potential to be exploited for improved clinical identification of these organisms as well as in the development of new vaccines and therapeutics targeted against the diseases caused by these organisms

Caractérisation d'une nouvelle famille d'ATPases ABC solubles chez Escherichia coli

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Etude génétique et structurale de Uup, une ATPase impliquée dans la recombinaison illégitime chez les bactéries

Au cours de ce travail de thèse, nous avons réalisé une étude génétique et structurale de la protéine Uup chez Escherichia coli. Cette protéine cytosolique, qui appartient à la superfamille des ATPases ABC ( ATP-binding cassette ), est impliquée dans la recombinaison illégitime chez les bactéries, à savoir l excision précise de transposons. La délétion du gène uup provoque un fort accroissement de la fréquence de cet évènement (pour les Tn10 et Tn5). Une telle augmentation est également observée chez des mutants conditionnels intervenant dans la réplication de l ADN. Tout d abord, Uup est constituée de deux domaines ATPasiques conservés et séparés par une région Linker de 75 résidus, ainsi que d un domaine carboxyl-terminal de 90 résidus. Étant donné qu Uup se fixe sur l ADN, d une part les paramètres de cette interaction ont été déterminés ; d autre part, le CTD et le Linker se sont révélés constituer deux domaines qui participent directement à la fixation d Uup sur l ADN. Notamment, le CTD a été caractérisé sur les plans biochimique et structural. Puis, afin d évaluer le rôle d Uup dans la réplication de l ADN, sa capacité de fixation sur des structures mimant des intermédiaires de réplication a été testée.Enfin, le double mutant priA et uup a été construit et s est avéré non viable. Ceci suggère que la fonction de PriA, protéine impliquée chez les bactéries dans le redémarrage des fourches de réplication bloquées, est essentielle dans un contexte dépourvu d UupPARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

ATP hydrolysis is essential for the function of the Uup ATP-binding cassette ATPase in precise excision of transposons

In Escherichia coli K-12, the RecA- and transposase-independent precise excision of transposons is thought to be mediated by the slippage of the DNA polymerase between the two short direct repeats that flank the transposon. Inactivation of the uup gene, encoding an ATP-binding cassette (ABC) ATPase, led to an important increase in the frequency of precise excision of transposons Tn10 and Tn5 and a defective growth of bacteriophage Mu. To provide insight into the mechanism of Uup in transposon excision, we purified this protein, and we demonstrated that it is a cytosolic ABC protein. Purified recombinant Uup binds and hydrolyzes ATP and undergoes a large conformational change in the presence of this nucleotide. This change affects a carboxyl-terminal domain of the protein that displays predicted structural homology with the socalled little finger domain of Y family DNA polymerases. In these enzymes, this domain is involved inDNAbinding and in the processivity of replication. We show that Uup binds to DNA and that this binding is in part dependent on its carboxyl-terminal domain. Analysis of Walker motif B mutants suggests that ATP hydrolysis at the two ABC domains is strictly coordinated and is essential for the function of Uup in vivo

Inventory and comparative analysis of rice and arabidopsis ATP-binding cassette (ABC) systems.

ATP-binding cassette (ABC) proteins constitute a large superfamily found in all kingdoms of living organisms. The recent completion of two draft sequences of the rice (Oryza sativa) genome allowed us to analyze and classify its ABC proteins and to compare to those in Arabidopsis thaliana. We identified a similar number of ABC proteins in rice and Arabidopsis (121 versus 120), despite the rice genome being more than three times the size of Arabidopsis. Both Arabidopsis and rice have representative members in all seven major subfamilies of ABC ATPases (A to G) commonly found in eukaryotes. This comparative analysis allowed the detection of 29 potential orthologous sequences in Arabidopsis and rice. However, plant share with prokaryotes a specific set of ABC systems that is not detected in animals. These ABC systems might be inherited from the cyanobacterial ancestor of chloroplasts. The present work provides the first complete inventory of rice ABC proteins and an updated inventory of those proteins in Arabidopsis

ABC systems: structural and functional variations on a common theme

International audienc

Structure, function, and evolution of bacterial ATP-binding cassette systems.

International audienceSUMMARY: ATP-binding cassette (ABC) systems are universally distributed among living organisms and function in many different aspects of bacterial physiology. ABC transporters are best known for their role in the import of essential nutrients and the export of toxic molecules, but they can also mediate the transport of many other physiological substrates. In a classical transport reaction, two highly conserved ATP-binding domains or subunits couple the binding/hydrolysis of ATP to the translocation of particular substrates across the membrane, through interactions with membrane-spanning domains of the transporter. Variations on this basic theme involve soluble ABC ATP-binding proteins that couple ATP hydrolysis to nontransport processes, such as DNA repair and gene expression regulation. Insights into the structure, function, and mechanism of action of bacterial ABC proteins are reported, based on phylogenetic comparisons as well as classic biochemical and genetic approaches. The availability of an increasing number of high-resolution structures has provided a valuable framework for interpretation of recent studies, and realistic models have been proposed to explain how these fascinating molecular machines use complex dynamic processes to fulfill their numerous biological functions. These advances are also important for elucidating the mechanism of action of eukaryotic ABC proteins, because functional defects in many of them are responsible for severe human inherited diseases