Biology Reference
In-Depth Information
three components of the 2-oxoglutarate dehydrogenase complex (PGN1755, KorB)
only the beta subunit showed an abundance increase.
Figure 4.
Thiamine biosynthetic pathway, showing protein abundance changes for the
P. gingivalis
-
F.
nucleatum
-
S. gordonii
/
P. gingivalis
comparison. Proteins catalyzing each step in the pathway are
shown by their
P. gingivalis
ATCC 33277
gene designation (PGN number) and protein name, where
applicable. Green downward arrows indicate decreased abundance in the three species community.
Yellow squares indicate no statistically significant abundance change. Empty squares indicate that
the protein was not detected in the proteomic analysis. Thiamine diphosphate is shown in bold.
Only incomplete pathways have been identifi ed for many of the other vitamin
biosynthesis activities in
P. gingivalis
. However, cobalamin (vitamin B12) synthesis
[38] can be predicted to be decreased in the community, with fi ve (PGN0010, CobC;
PGN0316, CbiG; PGN0317, CobL; PGN0318, CobH/CbiC; PGN0735, CobU) of the
seven identifi ed proteins having statistically signifi cant reductions. Less complete
population of pathways was observed for pyridoxal phosphate (vitamin B6) and biotin
synthesis. Only two of the four detected proteins for vitamin B6 synthesis showed re-
duced abundance (PGN1359, PdxB and PGN2055, PdxA). For biotin synthesis, three
of the six detected proteins showed reduced abundance (PGN0133, BioA; PGN1721,
BioF; PGN1997, BioD). None of the vitamin/cofactor synthesis pathways showed any
indication of increased protein levels in the three species community.
The decrease in several vitamin/cofactor pathways could be due to a decreased
utilization of those cofactors. However, in the case of thiamine, the proteins that utilize
this cofactor showed no decrease, and a possible increase in abundance, implying that
demand for vitamin B1 was unchanged. A more likely explanation for the reduced
cofactor pathways is therefore nutrient transfer. Either one or both of the other organ-
isms in the three species community could be providing
P. gingivalis
with cofactors,
