Crystallographic analysis of the recognition of a nuclear localization signal by the nuclear import factor karyopherin alpha

Cell. 1998 Jul 24;94(2):193-204. doi: 10.1016/s0092-8674(00)81419-1.


Selective nuclear import is mediated by nuclear localization signals (NLSs) and cognate transport factors known as karyopherins or importins. Karyopherin alpha recognizes "classical" monopartite and bipartite NLSs. We report the crystal structure of a 50 kDa fragment of the 60 kDa yeast karyopherin alpha, in the absence and presence of a monopartite NLS peptide at 2.2 A and 2.8 A resolution, respectively. The structure shows a tandem array of ten armadillo repeats, organized in a right-handed superhelix of helices. Binding of the NLS peptide occurs at two sites within a helical surface groove that is lined by conserved residues. The structure reveals the determinants of NLS specificity and suggests a model for the recognition of bipartite NLSs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, Polyomavirus Transforming / chemistry
  • Asparagine / chemistry
  • Binding Sites
  • Crystallography, X-Ray
  • Dimerization
  • Models, Molecular*
  • Molecular Sequence Data
  • Nuclear Localization Signals*
  • Nuclear Proteins / chemistry*
  • Saccharomyces cerevisiae / chemistry
  • Simian virus 40 / chemistry
  • Solvents
  • Tryptophan / chemistry
  • alpha Karyopherins


  • Antigens, Polyomavirus Transforming
  • Nuclear Localization Signals
  • Nuclear Proteins
  • Solvents
  • alpha Karyopherins
  • Asparagine
  • Tryptophan

Associated data

  • PDB/1BK5
  • PDB/1BK6