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Prevalence of a calcium‐based alkaline phosphatase associated with the marine cyanobacterium Prochlorococcus and other ocean bacteria
Author(s) -
Kathuria Satish,
Martiny Adam C.
Publication year - 2011
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2010.02310.x
Subject(s) - prochlorococcus , alkaline phosphatase , biology , phosphatase , phosphate , zinc , biochemistry , bacteria , enzyme , calcium , cyanobacteria , synechococcus , chemistry , genetics , organic chemistry
Summary Phosphate plays a key role in regulating primary productivity in several regions of the world's oceans and here dissolved organic phosphate can be an important phosphate source. A key enzyme for utilizing dissolved organic phosphate is alkaline phosphatase and the pho A‐type of this enzyme has a zinc cofactor. As the dissolved zinc concentration is low in phosphate depleted environments, this has led to the hypothesis that some phytoplankton may be zinc‐P co‐limited. Recently, it was shown that many marine bacteria contain an alternative form of alkaline phosphatase called pho X, but it is unclear which marine lineages carry this enzyme. Here, we describe the occurrence in low phosphate environments of pho X that is associated with uncultured Prochlorococcus and SAR11 cells. Through heterologous expression, we demonstrate that pho X encodes an active phosphatase with a calcium cofactor. The enzyme also functions with magnesium and copper, whereas cobalt, manganese, nickel and zinc inhibit enzyme activity to various degrees. We also find that uncultured SAR11 cells and cyanophages contain a different alkaline phosphatase related to a variant present in several Prochlorococcus isolates. Overall, the results suggest that many bacterial lineages including Prochlorococcus and SAR11 may not be subject to zinc‐P co‐limitation.