2ERB: Agamobp1, And Odorant Binding Protein From Anopheles Gambiae Complexed With Peg

The Anopheles gambiae mosquito is the main vector of malaria transmission in sub-Saharan Africa. We present here a 1.5A crystal structure of AgamOBP1, an odorant binding protein (OBP) from the A. gambiae mosquito. The protein crystallized as a dimer with a unique binding pocket consisting of a continuous tunnel running through both subunits of the dimer and occupied by a PEG molecule. We demonstrate that AgamOBP1 undergoes a pH dependent conformational change that is associated with reduced ligand binding. A predominance of acid-labile hydrogen bonds involving the C-terminal loop suggests a mechanism in which a drop in pH causes C-terminal loop to open, leaving the binding tunnel solvent exposed, thereby lowering binding affinity for ligand. Because proteins from two distantly related insects also undergo a pH dependent conformational change involving the C-terminus that is associated with reduced ligand affinity, our results suggest a common mechanism for OBP activity.
PDB ID: 2ERBDownload
MMDB ID: 36825
PDB Deposition Date: 2005/10/24
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 2ERB: monomeric; determined by author and by software (PISA)
Molecular Components in 2ERB
Label Count Molecule
Protein (1 molecule)
Odorant Binding Protein
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB