Download MendeleyBuried polar residues in coiled-coil interfaces.
Akey, D.L., Malashkevich, V.N., Kim, P.S.(2001) Biochemistry 40: 6352-6360
- PubMed: 11371197 Search on PubMed
- DOI: https://doi.org/10.1021/bi002829w
- Primary Citation Related Structures:
1IJ0, 1IJ1, 1IJ2, 1IJ3 - PubMed Abstract:
Coiled coils, estimated to constitute 3-5% of the encoded residues in most genomes, are characterized by a heptad repeat, (abcdefg)(n), where the buried a and d positions form the interface between multiple alpha-helices. Although generally hydrophobic, a substantial fraction ( approximately 20%) of these a- and d-position residues are polar or charged. We constructed variants of the well-characterized coiled coil GCN4-p1 with a single polar residue (Asn, Gln, Ser, or Thr) at either an a or a d position. The stability and oligomeric specificity of each variant were measured, and crystal structures of coiled-coil trimers with threonine or serine at either an a or a d position were determined. The structures show how single polar residues in the interface affect not only local packing, but also overall coiled-coil geometry as seen by changes in the Crick supercoil parameters and core cavity volumes.
- Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA.
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