Publications | Diamond News Autumn 2009

Diamond News Autumn 2009

Diamond celebrates 100th protein structure: Recognising sex pheromone components of silkworm moth

Silkworm moth or Bombyx mori are being used by biologists as a model organism in the study of the moth and butterfly family, which is known as Lepidopterans and includes over 180,000 species.

 Protein structure
Protein structure
As part of the study undertaken by Dr Jing-Jiang Zhou and colleagues at Rothamsted Research, the largest agricultural research centre in the United Kingdom and almost certainly the oldest agricultural research station in the world, in collaboration with Prof. Nick Keep’s group from the Institute of Structural and Molecular Biology at Birkbeck, University of London, new proteins were identified to be involved in the detection of odours relating to mating behaviour in silkworm moth. The work is published in Journal of Molecular Biology 2009 Jun 12;389(3):529-545.

Many insects depend on semiochemical molecules such as pheromones to communicate with each other and find a suitable mate or host volatiles to locate food. There are two main sex pheromone components bombykol and bombykal in the silkworm moth. Bombykol, the first insect pheromone discovered 50 years ago is the only component involved in mating behaviour whereas bombykal is an antagonist. So far, we know that odorant binding proteins (OBPs) within the organism pick up pheromones at pores on the outside of the antenna and carry them through a watery layer to the nerve endings. But it is not clear whether they simply transport and release molecules which bind to olfactory receptors or whether they form a specific OBP- pheromone complex which activates the receptor.

Dr Jing-Jiang Zhou, Senior Research Scientist in insect molecular biology at Rothamsted Research, is involved in the study on the molecular basis of insect olfactionand chemical ecology.

“The data disagrees with previous claims that one of the OBPs expressed in the moths (BmorPBP1) bound only to bombykol and that another OBP (BmorGOBP2) bound to compounds from the host plants. In fact, both bind to bombykol and bombykal, but BmorGOBP2 is capable of differentiating between them. The structures we determined using crystallography capabilities at Diamond provide us with information to explain these data and insights how it works.”

Dr Jing-Jiang Zhou, Rothamsted Research

Understanding how insects ‘smell’ and how the chemical signals are recognised is useful amongst others things for pest control in agriculture. Determining the composition and processes behind the olfactory functions of insects could lead to the development of new pathways to influence insect behaviours. Beyond this, there may also be some relevance to the development of biosensors by designing devices that would use proteins developed by nature to detect other molecules in very low concentration.

“This structure is the 100th now solved at Diamond and illustrates the fascinating range of structural biology in the UK. Congratulations to the Rothamsted and Birkbeck groups; thanks to productive groups like these, there is currently an exponential growth in the number of structures solved at Diamond so we hope to reach 200 structures during 2010.”

Prof. Dave Stuart, Life Sciences Director, Diamond Light Source

Characterisation of Bombyx mori Odorant-binding proteins reveals that a general odorant-binding protein discriminates between sex pheromone components , Journal of Molecular Biology 2009 Jun 12;389(3):529-545.

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