Characterisation of two calmodulin-like proteins from the liver fluke, Fasciola hepatica

✍ Scribed by Russell, Sean L.; McFerran, Neil V.; Hoey, Elizabeth M.; Trudgett, Alan; Timson, David J.

• Book ID: 121261377
• Publisher: Walter de Gruyter GmbH & Co. KG
• Year: 2007
• Tongue: English
• Weight: 301 KB
• Volume: 388
• Category: Article
• ISSN: 1431-6730
• DOI: 10.1515/BC.2007.076

✦ Synopsis

Abstract

Calmodulin is a calcium ion-sensing signalling protein found in eukaryotics. Two calmodulin-like gene sequences were identified in an EST library from adult liver flukes. One codes for a protein (FhCaM1) homologous to mammalian calmodulins (98% identity), whereas the other protein (FhCaM2) has only 41% identity. These genes were cloned into expression vectors and the recombinant proteins were expressed in__Escherichia coli__. Gel shift assays showed that both proteins bind to calcium, magnesium and zinc ions. Homology models have been built for both proteins. As expected, FhCaM1 has a highly similar structure to other calmodulins. Although FhCaM2 has a similar fold, its surface charge is higher than FhCaM1. One of the potential metal ion-binding sites has lower metal-ion co-ordination capability, while another has an adjacent lysine residue, both of which may decrease the metal-binding affinity. These differences may reflect a specialised role for FhCaM2 in the liver fluke.