Some pathogenic bacteria including Haemophilus influenzae and Neisseria
meningitides produce a protease called IgA1 protease to impair a major antibody,
immunoglobulin A1 (IgA1), on human mucosal surfaces. The iga mRNA is
initially translated into a precursor containing four distinct domains: a 31-amino
acids signal peptide which leads the precursor to the periplasmic space, an
105-kDa protease domain which cleaves host IgA1 molecule, a £]-domain
responsible for autotransportation of the protease domain, and a short linker
between the protease and the £]-domains. The autotransporter £]-domain can be
further divided into three subdomains in Neisseria protease: an extracellular
linking region £\-protein and a membrane-embedded £]-core, between which there
is a distinguished sequence called surface region. The hydrolytic function of the
protease and the transporter role of £]-core had been studied extensively, but the
£\-protein and the surface regions were less defined, or had their role
characterized. Thus this study is designed to reveal the possible pathogenic
functions of the £\-protein and the surface region in bacterial adherence to human
cell surfaces. To complete this project, recombinant £\-protein and the surface
region were expressed in IgA1 protease-negative E. coli strain (UT5600)
respectively and purified to homogeneity. These recombinant proteins were used
in cellular assays for bacterial adhesion on human lung cancer cell (A549). Four
different invasive strains of pathogenic bacteria (IgA1 protease-positive or
negative), were recruited in adherence assays to determine the effect of the
purified £\-protein and the surface region on bacterial adherence to A549 cells.
Results showed that the both £\-protein and the surface region played a role in
bacterial adherence in a species-dependent manner.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0803106-022942 |
| Date | 03 August 2006 |
| Creators | Su, Yu-ni |
| Contributors | Hsin-chih Lai, Shiping He, Jong-kang Liu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803106-022942 |
| Rights | unrestricted, Copyright information available at source archive |
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