HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Lam, S. L. Articles by Schryvers, A. B. Search for Related Content PubMed PubMed Citation Articles by Lam, S. L. Articles by Schryvers, A. B. Agricola Articles by Lam, S. L. Articles by Schryvers, A. B.

Foreign signal peptides can constitute a barrier to functional expression of periplasmic proteins in Haemophilus influenzae

Department of Microbiology and Infectious Diseases, Faculty of Medicine, University of Calgary, Heritage Medical Research Building, 3300 Hospital Dr. NW, Calgary, Alberta, Canada T2N 4N1

Correspondence
Anthony B. Schryvers
schryver{at}ucalgary.ca

To study the periplasmic branch of iron (ferric ion) uptake systems in Gram-negative bacteria, genetic reconstitution experiments were initiated in Haemophilus influenzae involving exchange of the periplasmic iron-binding protein. The expression of many of the heterologous periplasmic ferric-binding proteins (FbpAs) was quite limited. Transformation experiments with the fbpA gene from Neisseria gonorrhoeae yielded two colony sizes with different phenotypic characteristics. The small colonies contained the intact N. gonorrhoeae fbpA gene and were deficient in utilization of transferrin iron. The large colonies contained hybrid H. influenzae/N. gonorrhoeae fbpA genes, were proficient in transferrin iron utilization and had enhanced levels of expression of FbpA. These hybrid genes included several that encoded the mature N. gonorrhoeae FbpA with the H. influenzae signal peptide. To more fully evaluate the effect of foreign signal peptides, a series of hybrid genes were prepared that exchanged the signal peptides from H. influenzae FbpA, N. gonorrhoeae FbpA and the TEM-1 -lactamase. The presence of the H. influenzae leader was required for functional expression of FbpAs and was shown to dramatically increase the level of -lactamase activity.