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Odorant binding protein
From Proteopedia
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======Protein conformations====== | ======Protein conformations====== | ||
The PBP has two pH-dependent conformations, with different ligand affinities: the [["open form" (A)]] and the [["close form" (B)]] <ref>DOI: 10.1074/jbc.274.43.30950</ref>. The pheromone bombykol, and the seventh α-helix loacated in the C terminus of the protein compete for the binding site. | The PBP has two pH-dependent conformations, with different ligand affinities: the [["open form" (A)]] and the [["close form" (B)]] <ref>DOI: 10.1074/jbc.274.43.30950</ref>. The pheromone bombykol, and the seventh α-helix loacated in the C terminus of the protein compete for the binding site. | ||
| - | In a nuetral pH (6.5-7) the protein is in the "open form" (A), in which | + | In a nuetral pH (6.5-7) the protein is in the "open form" (A), in which the |
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| + | The C terminus of the protein bears mostly [[nonpolar amino acids]]. Yet on the surface of the helix there are three exceptional amino acids: Asp-132, Glu-137, and Glu-141, which are conserved in moth PBP <ref>10.1016/j.bbrc.2005.07.176</ref>. | ||
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| + | . Of these, residues Asp-132 and Glu-141 form a molecular switch, which upon protonation at low pH triggers the formation of the C-terminal α-helix (101). | ||
*[["open form" (A)]] | *[["open form" (A)]] | ||
Revision as of 15:04, 9 January 2015
Contents |
Introduction
Odorant-binding protein (OBP) are soluble proteins which involve in the processes of odorant detection in the olfactory sensilla.
The first OBP that was identified is Bovine odorant binding protein, that was isolated from a cow's mucus ref. Though functunaly same, vertebrates and insects OBP are stucture and different.
OBPs are important for insect olfaction. For instance, OBP76a (LUSH) in the fly Drosophila melanogaster is required for the detection of the pheromone vaccenyl acetate [Ha and Smith, 2006; Xu et al., 2005] and has been proven to adopt a conformation that activates the odorant receptor [Laughlin et al., 2008].
OBP in insects
OBP Function
Despite three decades of intensive research, the exact roles of OBP and the mechanism by which the odorant receptor (OR) is activated are still in dispute [1][2]. Of all, the role of OBP as an odorant carrier is generally accepted.
A few functions have been suggested for OBP: 1. 2. 3. 4.
In order to explain the structure and function of these fascinating proteins, this page will further focus on a particular OBP - the well investigated Bombyx mori PBP: BmorPBP.
PBP
PBPs are specialized members of the insect odorant-binding protein (OBP) super-family, and they are devided into three groups by their lengths: long-chain PBPs (∼160 aa), medium-chain PBPs (∼120 aa), and short-chain PBPs (∼110 aa) [3]
Bombyx mori BmorPBP (lets talk about sex..)
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See also
References
Proteopedia Page Contributors and Editors (what is this?)
Nurit Eliash, Michal Harel, Joel L. Sussman, Alexander Berchansky, Jaime Prilusky
