Page 6 - Molecular Pathogens

Molecular Pathogens 2012, Vol.3, No.1, 1-5
http://mp.sophiapublisher.com
3
domain proteins involved in virulence in Xcc 8004.
Although these proteins were almost different at the
level of global domain architecture, some of them
indeed shared common domain architecture based on
local comparison. We found that the proteins encoded
by XC _1476 , XC _2324 , XC_ 1582 and XC_ 1841
containing the GGDEF-EAL, whereas XC_1476 ,
XC_2324 and XC_637 all contained PAS_4-GGDEF.
Data analysis of other reports also found that the
PAS_4- GGDEF was common domain architecture in
the GGDEF domain proteins associated with
pathogenesis. Mao et al (2011) assayed the virulence
of GGDEF and EAL domain gene mutants using an
alternative experimental procedure instead of that in
Ryan et al (2007) used previously, the strains with a
single gene mutation in XC_637, XC_1036, XC_ 1476,
XC_2226 , XC_2324 and XC_ 4313 were tested under
different conditions of illumination. The domain
architectures in GGDEF domain protein which involved
in enhancing virulence of Xcc under strong light were
compared. The results indicated these three proteins
encoded by XC_ 1476, XC_2324 and XC_ 3829 respec-
tively shared the common domain, PAS_4-GGDEF.
Whereas the protein which had the architecture of
PAS-GGDEF encoded by XC_1036 played a role in
enhancing virulence of Xcc under weak light (Figure
3). To our knowledge, PAS_4-GGDEF was the first
common domain architecture that participated in
enhancing virulence of Xcc in response to strong light.
Figure 3 Comparison of domain architecture of GGDEF
domain protein involved in enhancing virulence of Xcc in
response to light intensity
1.2.2 Domain architecture in GGDEF domain
proteins involved in the production of extracellular
enzyme in Xcc 8004
Ryan et al (2007) assayed the enzyme production
ability of all the mutants of Xcc 8004 containing the
GGDEF domain proteins. The results indicated that 7
GGDEF domain proteins encoded by XC_ 637,
XC_2228, XC_2275, XC_2276, XC_1582, XC_1841
and XC_3829 were found to be involved in the
production of endoglucanase, major extracellular
enzymes (Figure 4). And we analyzed the domain
architecture. The result revealed that none of them had
a common architecture but some of them shared the
common structural elements, based on local comparison
that the domain architectures, f PAS_4-GGDEF and
PAS_4-PAS_4, which were in both of the proteins
encoded by XC_637 and XC_ 3829; GGDEF-EAL
contained by the protein encoded by XC_2228, XC_ 2276,
XC_1582 and XC_1841 (Figure 4).
Figure 4 Domain architecture of GGDEF domain proteins
involved in endoglucanase production in Xcc 8004
Note: a: Endoglucanase assay using NYGB medium; b:
Endoglucanase assay using MME medium; c: Endoglucanase
assay using AGF medium
1.2.3 Domain architecture of GGDEF domain
proteins involved in biofilm formation in Xcc 8004
Ryan et al (2007) assayed the formation ability of
biofilm in GGDEF mutations, the results indicated
that only 2 GGDEF domain proteins encoded by
XC_2161 and XC_2324 respectively were found to be
involved in biofilm formation in Xcc 8004. While we
analyzed the domain architectures of both of them, the
results revealed that both these proteins shared neither
common nor local common domain architecture
(Figure 5). A2M-comp domain was found between
GGDEF and EAL domain in XC_ 2161 -encoding
protein, whereas GGDEF domain was shown adjacent
to EAL domain in the protein coded by XC_ 2324
(Figure 5).