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Odorant binding protein
From Proteopedia
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| - | In order to explain the structure and function of these fascinating proteins, this page will further focus on a particular OBP - the well investigated ''[http://en.wikipedia.org/wiki/Bombyx_mori Bombyx mori]'' PBP: <scene name='68/683383/Bmorpbp_without_ligand/1'>BmorPBP | + | In order to explain the structure and function of these fascinating proteins, this page will further focus on a particular OBP - the well investigated ''[http://en.wikipedia.org/wiki/Bombyx_mori Bombyx mori]'' PBP: <scene name='68/683383/Bmorpbp_without_ligand/1'>BmorPBP</scene>. |
====PBP==== | ====PBP==== | ||
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====''Bombyx mori'' BmorPBP (lets talk about sex..)==== | ====''Bombyx mori'' BmorPBP (lets talk about sex..)==== | ||
| - | <StructureSection load=' | + | <StructureSection load='1dqe' size='340' side='right' caption='''Bombyx mori'' PBP and his ligand - the moth pheromone [[bombykol]]' scene=''> |
====BmorPBP structure and function==== | ====BmorPBP structure and function==== | ||
| - | This protein was first | + | This protein was first identified in the ''B. mori'' antennae by Krieger et al. in 1996 <ref>doi: 10.1016/0965-1748(95)00096-8</ref> . |
| - | has | + | It has 164 amino acids that forms 6-7 alpha helices. Three 3 disulfide bonds formed by 6 cystein residues tied four helices: disulfide 41-76 between H1 and H3, 72-130 between H3 and H6, and 1149-139 between H6 and H5. |
| - | + | ||
| - | + | ||
| - | + | ||
| - | + | ||
======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. | ||
| + | In a nuetral pH (6.5-7) the protein is in the "open form" (A), in which | ||
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*[["open form" (A)]] | *[["open form" (A)]] | ||
*[["close form" (B)]] | *[["close form" (B)]] | ||
| + | |||
| + | *'''The pH dependent theory''' | ||
| + | According to this theory, | ||
====Receptor activation==== | ====Receptor activation==== | ||
Revision as of 13:59, 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
OBPFunction
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: .
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
- ↑ Leal WS. Odorant reception in insects: roles of receptors, binding proteins, and degrading enzymes. Annu Rev Entomol. 2013;58:373-91. doi: 10.1146/annurev-ento-120811-153635. Epub, 2012 Sep 27. PMID:23020622 doi:http://dx.doi.org/10.1146/annurev-ento-120811-153635
- ↑ Kaissling KE. Olfactory perireceptor and receptor events in moths: a kinetic model revised. J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2009 Oct;195(10):895-922. , doi: 10.1007/s00359-009-0461-4. Epub 2009 Aug 21. PMID:19697043 doi:http://dx.doi.org/10.1007/s00359-009-0461-4
- ↑ Pesenti ME, Spinelli S, Bezirard V, Briand L, Pernollet JC, Tegoni M, Cambillau C. Structural basis of the honey bee PBP pheromone and pH-induced conformational change. J Mol Biol. 2008 Jun 27;380(1):158-69. Epub 2008 Apr 27. PMID:18508083 doi:10.1016/j.jmb.2008.04.048
- ↑ J. Krieger, E. von Nickisch-Rosenegk, M. Mameli, P. Pelosi, H. Breer. Binding proteins from the antennae of Bombyx mori. Insect Biochemistry and Molecular Biology, Volume 26, Issue 3, March 1996, Pages 297-307 doi:http://dx.doi.org/10.1016/0965-1748(95)00096-8
- ↑ Hubert Wojtasek and Walter S. Leal. Conformational Change in the Pheromone-binding Protein fromBombyx mori Induced by pH and by Interaction with Membranes, 1999 The Journal of Biological Chemistry, 274, 30950-30956. doi:http://dx.doi.org/10.1074/jbc.274.43.30950
- ↑ Thomas A Keil, Surface coats of pore tubules and olfactory sensory dendrites of a silkmoth revealed by cationic markers, Tissue and Cell (1984), Vol 16, Issue 5, 705-717 doi:http://dx.doi.org/10.1016/0040-8166(84)90004-1
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