Structure determination of the major outer membrane protein from Campylobacter jejuni & Structural and functional studies of the endonuclease from Lassa virus

Abstract

The major outer membrane protein, MOMP, is the main protein in the outer membrane of pathogenic Campylobacter bacteria. Infection with Campylobacter is the principle cause of severe enteritis and untreated may result in non-trauma related paralysis. Studies have shown, that MOMP can act as antigen and thus has the potential to provide protection by induced humoral immunity. In our study, we expressed recombinant MOMP in Escherichia1coli, developed an alternative method to extract the outer membrane protein from its lipid environment and solved and characterised its crystal structure. The information acquired through these structural studies sheds new light on the structural characteristics of this important membrane protein.

The West-African Lassa virus can cause deadly haemorrhagic fever. Lassa virus only possesses five proteins, which are synergistically responsible for the virus’ life cycle, and virulence. The way in which the individual proteins act with one another and with host cell proteins is not fully understood. The polymerase L is the largest of the five proteins and has multiple functions. In this study, we first divided the L protein into different domains and tested their recombinant expression in Escherichia1coli. For first time, we solved the crystal structure of the putative endonuclease domain of Lassa virus and validated its endonucleolytic function by means of RNA digestion assays and alanine point mutations.