Download MendeleySolution structure of the spectrin repeat: a left-handed antiparallel triple-helical coiled-coil.
Pascual, J., Pfuhl, M., Walther, D., Saraste, M., Nilges, M.(1997) J Mol Biol 273: 740-751
- PubMed: 9356261
- DOI: https://doi.org/10.1006/jmbi.1997.1344
- Primary Citation of Related Structures:
1AJ3 - PubMed Abstract:
Cytoskeletal proteins belonging to the spectrin family have an elongated structure composed of repetitive units. The three-dimensional solution structure of the 16th repeat from chicken brain alpha-spectrin (R16) has been determined by NMR spectroscopy and distance geometry-simulated annealing calculations. We used a total of 1035 distance restraints, which included 719 NOE-based values obtained by applying the ambiguous restraints for iterative assignment (ARIA) method. In addition, we performed a direct refinement against 1H-chemical shifts. The final ensemble of 20 structures shows an average RMSD of 1.52 A from the mean for the backbone atoms, excluding loops and N and C termini. R16 is made up of three antiparallel alpha-helices separated by two loops, and folds into a left-handed coiled-coil. The basic unit of spectrin is an antiparallel heterodimer composed of two homologous chains, beta and alpha. These assemble a tetramer via a mechanism that relies on the completion of a single repeat by association of the partial repeats located at the C terminus of the beta-chain (two helices) and at the N terminus of the alpha-chain (one helix). This tetramer is the assemblage able to cross-link actin filaments. Model building by homology of the "tetramerization" repeat from human erythrocyte spectrin illuminates the possible role of point mutations which cause hemolytic anemias.
Organizational Affiliation:
European Molecular Biology Laboratory, Meyerhofstr. 1, Heidelberg, 69012, Germany.
