TY - JOUR
T1 - Identification and characterization of KpsS, a novel polysaccharide sulphotransferase in Mesorhizobium loti
AU - Townsend, Guy E.
AU - Keating, David H.
PY - 2008/6
Y1 - 2008/6
N2 - Plants enter into symbiotic relationships with bacteria that allow survival in nutrient-limiting environments. The bacterium Mesorhizobium loti enters into a symbiosis with the legume host, Lotus japonicus, which results in the formation of novel plant structures called root nodules. The bacteria colonize the nodules, and are internalized into the cytoplasm of the plant cells, where they reduce molecular dinitrogen for the plant. Symbiosis between M. loti and L. japonicus requires bacterial synthesis of secreted and cell-surface polysaccharides. We previously reported the identification of an unusual sulphate-modified form of capsular polysaccharide (KPS) in M. loti. To better understand the physiological function of sulphated KPS, we isolated the sulphotransferase responsible for KPS sulphation from M. loti extracts, determined its amino acid sequence and identified the corresponding M. loti open reading frame, mll7563 (which we have named kpsS). We demonstrated that partially purified KpsS functions as a fucosyl sulphotransferase in vitro. Furthermore, mutants deficient for this gene exhibit a lack of KPS sulphation and a decreased rate of nodule formation on L. japonicus. Interestingly, the kpsS gene product shares no significant amino acid similarity with previously identified sulphotransferases, but exhibited sequence identity to open reading frames of unknown function in diverse bacteria that interact with eukaryotes.
AB - Plants enter into symbiotic relationships with bacteria that allow survival in nutrient-limiting environments. The bacterium Mesorhizobium loti enters into a symbiosis with the legume host, Lotus japonicus, which results in the formation of novel plant structures called root nodules. The bacteria colonize the nodules, and are internalized into the cytoplasm of the plant cells, where they reduce molecular dinitrogen for the plant. Symbiosis between M. loti and L. japonicus requires bacterial synthesis of secreted and cell-surface polysaccharides. We previously reported the identification of an unusual sulphate-modified form of capsular polysaccharide (KPS) in M. loti. To better understand the physiological function of sulphated KPS, we isolated the sulphotransferase responsible for KPS sulphation from M. loti extracts, determined its amino acid sequence and identified the corresponding M. loti open reading frame, mll7563 (which we have named kpsS). We demonstrated that partially purified KpsS functions as a fucosyl sulphotransferase in vitro. Furthermore, mutants deficient for this gene exhibit a lack of KPS sulphation and a decreased rate of nodule formation on L. japonicus. Interestingly, the kpsS gene product shares no significant amino acid similarity with previously identified sulphotransferases, but exhibited sequence identity to open reading frames of unknown function in diverse bacteria that interact with eukaryotes.
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U2 - 10.1111/j.1365-2958.2008.06215.x
DO - 10.1111/j.1365-2958.2008.06215.x
M3 - Article
C2 - 18430142
AN - SCOPUS:43449129719
SN - 0950-382X
VL - 68
SP - 1149
EP - 1164
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 5
ER -