Related Experiment Video
Updated: Jun 17, 2026
Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
Crystal structure of the OrfX1-OrfX3 complex from the PMP1 neurotoxin gene cluster
1Department of Biochemistry and Biophysics, Stockholm University, Sweden.
Abstract:
Paraclostridial mosquitocidal protein 1 (PMP1) is a member of the clostridial neurotoxin (CNT) family, which includes botulinum and tetanus neurotoxins. PMP1 has unique selectivity for anopheline mosquitos and is the only known member of the family that targets insects. PMP1 is encoded in an orfX gene cluster, which in addition to the toxin, consists of OrfX1, OrfX2, OrfX3, P47 and NTNH, which have been shown to aid in PMP1 toxicity. We here show that OrfX1 and OrfX3 form a complex and present its structure at 2.7 Å. The OrfX1-OrfX3 complex mimics the structure of full-length OrfX2 and belongs to the lipid-binding TULIP protein superfamily. With this report, the structures of all proteins encoded in the orfX gene cluster of CNTs are now determined.
Insights
Paraclostridial mosquitocidal protein 1 (PMP1) aids in insecticidal activity. Researchers determined the structure of the OrfX1-OrfX3 complex, completing the structural analysis of all proteins in the PMP1 gene cluster.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Entomology
Background:
- Paraclostridial mosquitocidal protein 1 (PMP1) is a unique insecticidal member of the clostridial neurotoxin (CNT) family.
- PMP1 targets anopheline mosquitoes, distinguishing it from other CNTs.
- PMP1 functions within a gene cluster (orfX) involving accessory proteins (OrfX1-3, P47, NTNH) that enhance its toxicity.
Purpose of the Study:
- To elucidate the structure of the OrfX1-OrfX3 complex.
- To complete the structural determination of all proteins within the orfX gene cluster associated with PMP1.
Main Methods:
- X-ray crystallography was employed to determine the structure of the OrfX1-OrfX3 complex.
- Structural analysis was performed at a resolution of 2.7 Å.
Main Results:
- The structure of the OrfX1-OrfX3 complex was determined at 2.7 Å resolution.
- This complex structurally mimics the full-length OrfX2 protein.
- The OrfX1-OrfX3 complex belongs to the lipid-binding TULIP protein superfamily.
Conclusions:
- The structural determination of the OrfX1-OrfX3 complex is now complete.
- This finding contributes to the comprehensive structural understanding of the PMP1 orfX gene cluster.
- All proteins encoded within the orfX gene cluster of CNTs have now had their structures determined.
