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Journal of Microbiology: Current Research | Volume 2
November 01-02, 2018 | London, UK
7
th
European
Clinical Microbiology Congress
4
th
International Conference on
Ophthalmology and Eye Disorder
Joint Event
&
The role of ActA in peptidoglycan remodelling in
Listeria monocytogenes
Ohoud S Alhumaidan, Nino Iakochvili, Peter W Andrew
and
Galina V Mukamolova
University of Leicester, UK
L
isteria monocytogenes
is a food-borne bacterial pathogen,
the causative agent of human listeriosis. It may cause
abortion in pregnant women, septicaemia, endocarditis
and meningitis in elderly people and immunocompromised
patients.
L. monocytogenes
has many virulence factors that
enable its replication in macrophages and the escape from
the phagolysosome to the cytoplasm. One of these virulence
factors is the actin-assembly inducing protein, ActA, that is
essential for
L. monocytogenes
intra- and intercellular motility.
Recently, the ActA protein has been shown to regulate
peptidoglycan (PG) biosynthesis during
L. monocytogenes
replication in macrophages. However, the exact mechanism
for this phenomenon is unknown. The central hypothesis
of the present study is that ActA possesses peptidoglycan
hydrolysing activity. To address this hypothesis three different
His-tagged forms of ActA have been expressed in
Escherichia
coli
. All versions have been successfully purified using affinity
chromatography, gel-filtration and their identity has been
confirmed by mass-spectrometry. Peptidoglycan hydrolysing
activity of these proteins has been assessed by application
of zymography and digestion of FITC-labelled peptidoglycan.
One domain showed significant peptidoglycan-hydrolysing
activity as judged by zymography and digestion of FITC-labelled
peptidoglycan. Candidate catalytic residues are currently being
identified by application of bioinformatics and their functionwill
be verified by site directed mutagenesis. Future experiments
such as analysis of muropeptides released from PG by ActA,
complementation studies and pull-down assays will shed light
on the function of this protein in peptidoglycan remodelling.
Speaker Biography
Ohoud S Alhumaidan is a 3
rd
year PhD student in infection, immunity and inflammation
department at University of Leicester. She is working under the supervision of Dr. Galina
Mukamolova and professor Peter Andrew. Her doctoral research investigates the role of
specific protein in
listeria monocytogenes
. She is a member of the microbiology society
and she holds master’s degree in microbiology from King Saud University, Saudi Arabia, in
isolation and characterisation of nasal carriage MRSA among health care staff in a teaching
hospital.
e:
osa16@le.ac.ukOhoud S Alhumaidan et al., Clinical Microbiology and Eye 2018, Volume 2
DOI: 10.4066/2591-8036-C1-003