The divergent domains of the NEFA and nucleobindin proteins are derived from an EF-hand ancestor.
The human protein NEFA (DNA binding, EF-hand, Acidic region) has previously been isolated from a KM3 cell line and immunolocalized on the plasma membrane, in the cytoplasma, and in the culture medium. Sequence analysis of a cDNA clone encoding NEFA identified a hydrophilic domain, two EF-hands, and a leucine zipper at the C-terminus. These characters are shared with nucleobindin (Nuc). In this paper we have further characterized NEFA and probed its evolutionary origins. Circular dichroism (CD) spectra of recombinant NEFA indicated a helical content of 51% and showed that the EF-hands are capable of binding Ca2+. Experiments with recombinant NEFA and synthesized peptides revealed that the leucine zipper cannot form a homodimer. The leucine zipper may allow heterodimer formation of NEFA and an unknown protein. Phylogenetic analyses suggest that this protein is derived from a four-domain EF-hand ancestor with subsequent duplications and fusions. The leucine zipper and putative DNA-binding domains of NEFA have evolved secondarily from existing EF-hand sequences. These analyses provide insights into how complex proteins may originate and trace the precursor of NEFA to the common ancestor of eukaryotes.
Karabinos
A
A
Department of Immunochemistry, Max Planck Institute for Experimental Medicine, Göttingen, Germany.
Bhattacharya
D
D
Morys-Wortmann
C
C
Kroll
K
K
Hirschfeld
G
G
Kratzin
H D
HD
Barnikol-Watanabe
S
S
Hilschmann
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004720:Endonucleases; D019143:Evolution, Molecular; D006801:Humans; D016350:Leucine Zippers; D008836:Micrococcal Nuclease; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D004268:DNA-Binding Proteins; C000630650:NUCB2 protein, human; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D010446:Peptide Fragments; C074002:nuc protein, staphylococcus; D004720:Endonucleases; D008836:Micrococcal Nuclease; D002118:Calcium