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Updated: Aug 5, 2026
From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
Crystallization and X-ray diffraction measurements on recombinant molbindin, MopII, from Clostridium pasteurianum
J A Harrison1, A W Schüttelkopf, D H Boxer
1School of Life Sciences, The Wellcome Trust Biocentre, University of Dundee, Dundee DD1 5EH, Scotland.
Abstract:
Clostridium pasteurianum carries three genes termed mopI, II and III encoding three molbindin isoforms, one of which has been cloned, the gene product expressed in high yield and crystallized using the hanging-drop vapour-diffusion method. Well ordered monoclinic crystals in two different crystal forms, both with space group C2, were obtained in the presence and absence of Na(2)MoO(4) and Na(2)WO(4). Ligand-bound MopII crystallized with polyethylene glycol (PEG) 400 as a precipitant, whereas apo MopII required PEG 6000. High-resolution diffraction data were collected for ligand-bound MopII structures using synchrotron radiation to 1.8 and 1.6 A resolution for the molybdate and tungstate complexes, respectively. Data were collected on apoMopII crystals to a resolution of 1.8 A in-house.
Insights
Researchers crystallized molbindin (MopII) from Clostridium pasteurianum, determining its structure with bound molybdate and tungstate ligands. This structural information is crucial for understanding molbindin
Area of Science:
- Biochemistry
- Structural Biology
- Crystallography
Background:
- Clostridium pasteurianum possesses three molbindin (mop) genes (mopI, II, III) encoding distinct isoforms.
- Molbindins are proteins involved in metal ion binding and transport.
Purpose of the Study:
- To clone, express, and crystallize a molbindin isoform (MopII) from Clostridium pasteurianum.
- To determine the high-resolution crystal structures of ligand-bound and apo MopII.
Main Methods:
- Gene cloning and protein expression in a high-yield system.
- Hanging-drop vapor-diffusion method for protein crystallization.
- X-ray diffraction data collection using synchrotron radiation and in-house sources.
- Structure determination of molybdate and tungstate complexes of MopII.
Main Results:
- Two distinct monoclinic crystal forms (space group C2) of MopII were obtained.
- Ligand-bound MopII crystallized with polyethylene glycol (PEG) 400, while apo MopII required PEG 6000.
- High-resolution diffraction data (1.6–1.8 Å) were collected for MopII structures.
Conclusions:
- Successful crystallization and structural determination of MopII provide insights into its ligand-binding capabilities.
- The structural data are essential for understanding the function of molbindins in metal ion homeostasis.
- This study lays the groundwork for further investigations into MopII's biological role and potential applications.
