title: Human erythrocyte dematin and protein 4.2 (pallidin) are ATP binding proteins.
abstract: Dematin and protein 4.2 are peripheral membrane proteins associated with the cytoplasmic surface of the human erythrocyte plasma membrane. Isoforms of dematin and protein 4.2 exist in many nonerythroid cells. In solution, dematin is a trimeric protein containing two subunits of 48 kDa and one subunit of 52 kDa. Recent determination of the primary structure of the 52 kDa subunit of dematin showed that it contains an additional 22-amino acid sequence in the headpiece domain. An alignment of the 22-amino acid insertion sequence revealed that the 52 kDa subunit of dematin shares a novel 11-amino acid motif with protein 4.2. In this communication, we report that the conserved 11-amino acid motif in dematin52 and protein 4.2 contains a nucleotide binding P-loop. Direct binding of ATP is demonstrated to the glutathione S-transferase fusion proteins containing corresponding segments of dematin52 and protein 4.2 as well as to purified protein 4.2. The binding of ATP to the recombinant domains of dematin52 and protein 4.2 is specific, saturable, and of high affinity. The nucleotide specificity of the P-loop is restricted to ATP since no detectable binding was observed with GTP. These results show that the 11-amino acid motif provides an ATP binding site in dematin52 and protein 4.2. Although the functional significance of ATP binding is not yet clear, our findings open new perspectives for the function of dematin and protein 4.2 in vivo.
authors.affiliation: Department of Biomedical Research, Laboratory of Tumor Cell Biology, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02135, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Azim
authors.forename: S M
authors.initials: SM
authors.lastname: Marfatia
authors.forename: C
authors.initials: C
authors.lastname: Korsgren
authors.forename: E
authors.initials: E
authors.lastname: Dotimas
authors.forename: C M
authors.initials: CM
authors.lastname: Cohen
authors.forename: A H
authors.initials: AH
authors.lastname: Chishti
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001798:Blood Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D017124:Conserved Sequence; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C044805:DMTN protein, human; D017931:DNA Primers; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C044791:erythrocyte membrane band 4.2 protein; D000255:Adenosine Triphosphate