PlsX and Related Proteins
The PlsX protein has gained recent attention. Here is the abstract from
Involvement of the YneS/YgiH and PlsX proteins in phospholipid biosynthesis in both Bacillus subtilis and Escherichia coli by
Mika Yoshimura, Taku Oshima, and Naotake Ogasawara,
which can be obtained using this link:
Background: Phospholipid biosynthesis commences with the acylation of
glycerol-3-phosphate (G3P) to form 1-acyl-G3P. This step is catalyzed
by the PlsB protein in Escherichia coli. The gene encoding this
protein has not been identified, however, in the majority of bacterial
genome sequences, including that of Bacillus subtilis. Recently, a new
two-step pathway catalyzed by PlsX and PlsY proteins for the
initiation of phospholipid formation in Streptococcus pneumoniae has
been reported.
Results: In B. subtilis, 271 genes have been reported to be
indispensable, when inactivated singly, for growth in LB medium. Among
these, 11 genes encode proteins with unknown functions. As part of a
genetic study to identify the functions of these genes, we show here
that the B. subtilis ortholog of S. pneumoniae PlsY, YneS, is required
for G3P acyltransferase activity, together with PlsX. The B. subtilis
genome lacks plsB, and we show in vivo that the PlsX/Y pathway is
indeed essential for the growth of bacteria lacking
plsB. Interestingly, in addition to plsB, E. coli possesses plsX and
the plsY ortholog, ygiH. We therefore explored the functional
relationship between PlsB, PlsX and YgiH in E. coli, and found that
plsB is essential for E. coli growth, indicating that PlsB plays an
important role in 1-acyl-G3P synthesis in E. coli. We also found,
however, that the simultaneous inactivation of plsX and ygiH was
impossible, revealing important roles for PlsX and YgiH in E. coli
growth.
Conclusion: Both plsX and yneS are essential for 1-acyl-G3P synthesis
in B. subtilis, in agreement with recent reports on their biochemical
functions. In E. coli, PlsB plays a principal role in 1-acyl-G3P
synthesis and is also essential for bacterial growth. PlsX and YgiH
also, however, play important roles in E. coli growth, possibly by
regulating the intracellular concentration of acyl-ACP. These proteins
are therefore important targets for development of new antibacterial
agents.
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