Unusual lipid binding proteins and allergens of parasitic nematodes

Unusual lipid binding proteins and allergens of parasitic nematodes

Following our previous focus on the immunology of infections with parasitic nematodes, and the genetic restriction of immune responses to the allergens they secrete, we moved on to examining the structure and function of several lipid binding proteins from nematodes that are either quite different from those found in other phyla, or are modified in unusual ways. These include As-p18, which typifies a lipid carrier in nematode eggs that may be involved in maintaining the protective lipid layer beneath the shell, ABA-1 (a member of the NPAs or Nematode Polyprotein Allergens), which derives from a strange tandemly repetitive polyprotein that is processed down to mutiple copies of a lipid carrier protein, and the FAR proteins, which are again highly unususal. The latter two types are secreted by the parasites into the tissues they occupy and are suspected of modifying the immune response of the infected host. With ABA-1 we have got so far as solving by nuclear magnetic resonance the solution structure of one of the mature units of the polyprotein. Not only is this structure novel, but it represents the first unit of a tandemly repeated polyprotein yet to be solved. This work involves a large number of collaborators, but the structural and biophysical work was carried out with Alan Cooper  ( http://www.chem.gla.ac.uk/staff/alanc/ )  and Brian Smith ( www.gla.ac.uk:443//ibls/staff/staff.php?who=|PQQAd ), and the ABA-1 structure was solved by Nicola Meenan, who was a PhD student here at the time.


Here is the NMR structure of ABA-1

Here is a model structure of As-p18