FhCaBP1 (FH22): A Fasciola hepatica calcium-binding protein with EF-hand and dynein light chain domains.
FH22 has been previously identified as a calcium-binding protein from the common liver fluke, Fasciola hepatica. It is part of a family of at least four proteins in this organism which combine an EF-hand containing N-terminal domain with a C-terminal dynein light chain-like domain. Here we report further biochemical properties of FH22, which we propose should be renamed FhCaBP1 for consistency with other family members. Molecular modelling predicted that the two domains are linked by a flexible region and that the second EF-hand in the N-terminal domain is most likely the calcium ion binding site. Native gel electrophoresis demonstrated that the protein binds both calcium and manganese ions, but not cadmium, magnesium, strontium, barium, cobalt, copper(II), iron (II), nickel, zinc, lead or potassium ions. Calcium ion binding alters the conformation of the protein and increases its stability towards thermal denaturation. FhCaBP1 is a dimer in solution and calcium ions have no detectable effect on the protein's ability to dimerise. FhCaBP1 binds to the calmodulin antagonists trifluoperazine and chlorpromazine. Overall, the FhCaBP1's biochemical properties are most similar to FhCaBP2 a fact consistent with the close sequence and predicted structural similarity between the two proteins.
School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
Sarah
S
Cheung
School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK; Institute for Global Food Security, Queen's University Belfast, 18-30 Malone Road, Belfast, BT9 5BN, UK.
Charlotte M
CM
Thomas
School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK; School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, UK. Electronic address: d.timson@brighton.ac.uk.
David J
DJ
Timson
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002746:Chlorpromazine / Q000378:metabolism; D004398:Dyneins / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005210:Fasciola hepatica / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D015801:Helminth Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D011487:Protein Conformation; D055503:Protein Multimerization; D014268:Trifluoperazine / Q000378:metabolism
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D015801:Helminth Proteins; D014268:Trifluoperazine; D008345:Manganese; D004398:Dyneins; C085577:Ca2+-binding protein-1; D002118:Calcium; D002746:Chlorpromazine
Calcium binding; Dynein light chain; EF-hand; Liver fluke; Neglected tropical disease; Trematode protein