Ca<SUP>2+</SUP> is a frequently utilised second messenger in higher plants. Calmodulin is a small, highly conserved, multi-site receptor for Ca<SUP>2=</SUP>, which interacts with a large number of downstream effector proteins. Calmodulin binding proteins (CBPs) do not have a highly conserved binding domain, and interact with calmodulin in an unusual fashion involving both a hydrophobic surface and charged domains. A number of techniques to isolate CBPs from plants were used. Techniques based on DNA homology suffer from the extreme lack of conservation between calmodulin binding domains. Other, established techniques, utilise <I>in vitro </I>overlays of labelled calmodulin to screen cDNA libraries, and are necessarily artificial and thus potentially artifactual. Algorithmic modelling of the calmodulin binding interaction based on up to date information was carried out using rapid, quantitative computer profiles which utilised a novel double profile technique to combine both hydrophobic and charge related patterns. This model suggests that a large number of relatively weak yet biologically significant CBPs are to be expected. The consequences of the presence of these proteins is discussed. The yeast dihybrid system was utilised as an <I>in vivo</I> system to screen for calmodulin binding proteins, and a number of sequences isolated and partially sequenced. These sequences demonstrate the success of this technique, and show the existence of a partially conserved calmodulin binding domain within the plant kingdom, as well as a high number of CBPs of potential biological significance.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661843 |
| Date | January 1997 |
| Creators | Shepherd, Jason |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14408 |
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