title: The linker of des-Glu84-calmodulin is bent.
abstract: The crystal structure of a mutant calmodulin (CaM) lacking Glu-84 has been refined to R = 0.23 using data measured to 2.9-A resolution. In native CaM the central helix is fully extended, and the molecule is dumbbell shaped. In contrast, the deletion of Glu-84 causes a bend of 95 degrees in the linker region of the central helix at Ile-85. However, EF-hand domains 1 and 2 (lobe 1,2) do not touch lobe 3,4. The length, by alpha-carbon separation, of des-Glu84-CaM is 56 A; that of native CaM is 64 A. The shape of des-Glu84-CaM is similar to that of native CaM, as it is bound to the target peptide of myosin light-chain kinase. This result supports the proposal that the linker region of the central helix of CaM functions as a flexible tether.
authors.affiliation: Department of Biology, University of Virginia, Charlottesville 22901.
authors.forename: S
authors.initials: S
authors.lastname: Raghunathan
authors.forename: R J
authors.initials: RJ
authors.lastname: Chandross
authors.forename: B P
authors.initials: BP
authors.lastname: Cheng
authors.forename: A
authors.initials: A
authors.lastname: Persechini
authors.forename: S E
authors.initials: SE
authors.lastname: Sobottka
authors.forename: R H
authors.initials: RH
authors.lastname: Kretsinger
mesh_terms: D000595:Amino Acid Sequence; D002147:Calmodulin / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
chemical_list: D002147:Calmodulin; C082348:des(Glu(84))-calmodulin