title: Actin binding of a minispectrin.
abstract: A "minispectrin" has been constructed from the tail end of the alpha/beta heterodimer, and its actin-binding properties have been characterised. It is a complex of the N-terminal fragment of the beta-subunit consisting of the actin-binding domain plus the two first triple-helical repeats beta 1 and beta 2, and the C-terminal fragment of the alpha-subunit containing the repeats alpha 19 and alpha 20 plus the calmodulin-like domain. This minispectrin exists in a dimeric form that contains one copy of each polypeptide and binds to actin in a cooperative manner with an apparent K(d) of 2.5 microM. Calcium seems not to have any effect on its binding to actin. Electron microscopic analysis shows that the minispectrin decorates actin filaments as clusters, and induces formation of actin bundles. This study shows that the actin-binding region of the spectrin alpha/beta heterodimer retains its functional properties in a truncated form and establishes basis for further research on spectrin's structure and function.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 102209, D-69012 Heidelberg, Germany. arnt.raae@mbi.uib.no
authors.forename: Arnt J
authors.initials: AJ
authors.lastname: Raae
authors.forename: Sonia
authors.initials: S
authors.lastname: Bañuelos
authors.forename: Jari
authors.initials: J
authors.lastname: Ylänne
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Olausson
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Goldie
authors.forename: Thomas
authors.initials: T
authors.lastname: Wendt
authors.forename: Andreas
authors.initials: A
authors.lastname: Hoenger
authors.forename: Matti
authors.initials: M
authors.lastname: Saraste
mesh_terms: D000185:Actinin / Q000737:chemistry*; D000199:Actins / Q000737:chemistry* / Q000648:ultrastructure; D002942:Circular Dichroism; D018076:DNA, Complementary / Q000096:biosynthesis; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005822:Genetic Vectors; D008854:Microscopy, Electron; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013049:Spectrin / Q000096:biosynthesis / Q000737:chemistry* / Q000648:ultrastructure; D014461:Ultracentrifugation
chemical_list: D000199:Actins; D018076:DNA, Complementary; D000185:Actinin; D013049:Spectrin