University of Leicester
U499827.pdf (39.17 MB)

Immunoglobulin a1 protease of Streptococcus pneumoniae.

Download (39.17 MB)
posted on 2015-11-19, 09:10 authored by Stephanie Ann. Pratt
The aim of this project was to examine the Streptococcal IgA1 proteases, with particular interest on the Streptococcus pneumoniae enzyme. IgA1 protease of S. pneumoniae was identified and characterised. A non-reducing polyacrylamide gel system was employed to screen clinical isolates for IgA1 protease activity. Of 187 isolates tested 18% were found to be IgA1 protease negative, there was no correlation with the site of isolation of the organism and its ability to produce the enzyme. Attempts were made to clone the pneumococcal IgA1 protease gene using the cosmid pEMBLcos4, the plasmid vector pLG339 and the ? replacement vector ?EMB4. Libraries were screened for pneumolysin and IgA1 protease activity. Clones that expressed pneumolysin were identified by overlaying with sheep red blood cells. One haemolytic clone was not inhibited in the presence of cholesterol. Screening for IgA1 protease activity identified clones with IgA1 protease-ike activity but this activity was not stably expressed. Closer analysis of the libraries suggested that pneumococcal DNA was highly unstable when cloned into E. coil plasmid and cosmid vectors.


Date of award


Author affiliation


Awarding institution

University of Leicester

Qualification level

  • Doctoral

Qualification name

  • PhD



Usage metrics

    University of Leicester Theses