A structural model of human erythrocyte band 2.1: alignment of chemical and functional domains.
Abstract
Protein 2.1 is a 210-kilodalton protein that connects erythrocyte spectrin to the NH2-terminal cytoplasmic domain of band 3 and thereby functions as the essential linkage between the membrane skeleton and the bilayer. We cleaved this protein into specific chemical domains by limited digestion with trypsin and alpha-chymotrypsin at 0 degrees C. Intermediate-sized peptides were separated by two-dimensional isoelectric focusing/NaDodSO4/polyacrylamide gel electrophoresis and characterized by high resolution peptide mapping. We have established a provisional structural model of protein 2.1 by comparing the peptide maps of these chemical domains to maps obtained from larger overlapping chymotryptic fragments as well as fragments obtained from 2-nitro-5-thiocyanobenzoic acid cleavage. In addition to providing a provisional structural map of protein 2.1, we have identified two functional domains of protein 2.1, an 83-kilodalton tryptic peptide (T-83) which binds band 3 and a 65-kilodalton tryptic peptide (T-65) which binds spectrin. We have therefore localized the functional domains along our linear map of protein 2.1.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- July 1984
- DOI:
- 10.1073/pnas.81.13.4095
- Bibcode:
- 1984PNAS...81.4095W