title: Functional and structural analysis of the conserved EFhd2 protein.
abstract: EFhd2 is a novel protein conserved from C. elegans to H. sapiens. This novel protein was originally identified in cells of the immune and central nervous systems. However, it is most abundant in the central nervous system, where it has been found associated with pathological forms of the microtubule-associated protein tau. The physiological or pathological roles of EFhd2 are poorly understood. In this study, a functional and structural analysis was carried to characterize the molecular requirements for EFhd2's calcium binding activity. The results showed that mutations of a conserved aspartate on either EF-hand motif disrupted the calcium binding activity, indicating that these motifs work in pair as a functional calcium binding domain. Furthermore, characterization of an identified single-nucleotide polymorphisms (SNP) that introduced a missense mutation indicates the importance of a conserved phenylalanine on EFhd2 calcium binding activity. Structural analysis revealed that EFhd2 is predominantly composed of alpha helix and random coil structures and that this novel protein is thermostable. EFhd2's thermo stability depends on its N-terminus. In the absence of the N-terminus, calcium binding restored EFhd2's thermal stability. Overall, these studies contribute to our understanding on EFhd2 functional and structural properties, and introduce it into the family of canonical EF-hand domain containing proteins.
authors.affiliation: Department of Biology, University of Puerto Rico-Rio Piedras Campus, San Juan, PR 00931, USA.
authors.forename: Yancy
authors.initials: Y
authors.lastname: Ferrer-Acosta
authors.forename: Eva N
authors.initials: EN
authors.lastname: Rodríguez Cruz
authors.forename: Ana del C
authors.initials: Adel C
authors.lastname: Vaquer
authors.forename: Irving E
authors.initials: IE
authors.lastname: Vega
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D020641:Polymorphism, Single Nucleotide; D011485:Protein Binding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
chemical_list: D002135:Calcium-Binding Proteins; C530752:EFHD2 protein, mouse; D011994:Recombinant Proteins; D002118:Calcium