P-type ATPases in Prokaryotes

P-type ATPases control cation homeostasis in many organismal types (Fagan and Saier 1994 Pahngren and Axelson 1998 De Hertogh et al. 2004 Haupt et al. 2005 Kuhlbrandt 2004 Chan et al. 2010 Thever and Saier 2009). As noted above, firmicutes, which have low numbers of CaCA family members, have 2-3 times as many Ca -ATPases as are found in actinobacteria and Gram (-) bacteria (Table 4.12). By contrast, archaea, which have good representation of CaCA carriers, also have excellent representation of the Ca -ATPases. 

Of great interest is the fact that LAB encode P-type ATPases (TC 3.A.3) in their genomes that normally occur in eukaryotes but not in most other bacteria. These include members of the families of NaL K+-exchange ATPases of animals (family 1 in TCDB), -ATPases of plants and fungi 

Our studies have identified P-t5ipe ATPases that do not fall into one of the ten functionally well-characterized families of these enzyme/transporters (TC 3.A.3.1-10 Chan et al. 2010 Thever and Saier, 2009). Altogether, we have identified about two dozen families, each represented only in eukaryotes or in prokaryotes, not in both. Some of the largest of these families, well represented in prokaryotes, are presented in Table 4.12. Molecular genetic, biochemical, and physiological experimentation will be required to determine the transport substrates of these enzymes. 

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