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Contents 1 Introduction 2 OBP in insects 2.1 PBP 2.2 Bombyx mori BmorPBP (lets talk about sex..) 2.2.1 BmorPBP Function 2.2.2 Protein conformations 2.2.3 Receptor activation i lepidoptora 3 See also 4 References

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. OBP in vertebrates

OBP in insects

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 categorized into three groups by their lengths: the long-chain PBPs (∼160 aa), the medium-chain PBPs (∼120 aa), and the short-chain PBPs (∼110 aa)

Bombyx mori BmorPBP (lets talk about sex..)

BmorPBP 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 leal 2013, kaissling. 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.

spinqualitylabelsall models PDB ID 1DQE Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image The BPB ligand is the moth pheromone

Protein conformations

• "open form" (A)
• "close form" (B)

Receptor activation i lepidoptora

• The pH theory

This theory is supported by several facts. First, it has been found that the BmPBP conformation is changing from its "open form" (A) to the "close form" (B) in a pH dependent manner wojtasek 1999, and that the two conformations has different ligand affinities.

???? Second, the surface of the dendrite is negatively charged Keil TA (1984) Surface coats of pore tubules and olfactory sensory dendrites of a silkmoth revealed by cationic markers. Tissue Cell 16(5):705–717, which cause the accumulation of positively charged kations near the membrane surface (20-50 nm), thereby inducing a low pH environment near the dendrite membrane kaissling 2009

Leal WS, et al. (2005) Kinetics and molecular properties of pheromone binding and release. Proc Natl Acad Sci USA 102(15):5386–5391.

• The other theory

See also

• Odorant_binding_protein_3D_structures

References