The identification and sequence of the actin-binding domain of human red blood cell beta-spectrin.
The junctions of the red blood cell membrane skeleton are formed by interactions between spectrin and actin protofilaments. A spectrin tryptic peptide of 16.5-kDa apparent molecular mass (based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis) which binds to F-actin in cosedimentation experiments has been identified. The peptide has been partially purified by gel filtration, anion-, and cation exchange chromatography. Intact spectrin heterodimer causes half-maximal inhibition of the 16.5-kDa peptide/F-actin interaction at a concentration of 5 microM. Comparison of the two-dimensional iodopeptide maps of the 16.5-kDa peptide with maps of alpha- and beta-spectrin, demonstrate that the peptide is generated from the beta subunit. It shows no significant relationship to the peptide maps of the beta-spectrin domains I-IV. Protein sequencing indicated that this actin-binding domain represents a stretch of amino acids at the N terminus of the beta subunit from alanine 47 probably through lysine 186. The sequence derived molecular weight of this actin-binding domain is 16,290 g/mol. The sequence presented represents the region of greatest homology among the spectrin supergene family (spectrin, dystrophin, alpha-actinin).
Karinch
A M
AM
Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033.
Zimmer
W E
WE
Goodman
S R
SR
D000199:Actins / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002850:Chromatography, Gel; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D013049:Spectrin / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014357:Trypsin
D000199:Actins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D013049:Spectrin; D014357:Trypsin