Structure, crystal packing and molecular dynamics of the calponin-homology domain of Schizosaccharomyces pombe Rng2

Acta Crystallogr D Biol Crystallogr. 2004 Aug;60(Pt 8):1396-403. doi: 10.1107/S0907444904012983. Epub 2004 Jul 21.


Schizosaccharomyces pombe Rng2 is an IQGAP protein that is essential for the assembly of an actomyosin ring during cytokinesis. Rng2 contains an amino-terminal calponin-homology (CH) domain, 11 IQ repeats and a RasGAP-homology domain. CH domains are known mainly for their ability to bind F-actin, although they have other ligands in vivo and there are only few examples of actin-binding single CH domains. The structures of several CH domains have already been reported, but this is only the third report of an actin-binding protein that contains a single CH domain (the structures of calponin and EB1 have been reported previously). The 2.21 A resolution crystal structure of the amino-terminal 190 residues of Rng2 from Br- and Hg-derivatives includes 40 residues (150-190) carboxyl-terminal to the CH domain that resemble neither the extended conformation seen in utrophin, nor the compact conformation seen in fimbrin, although residues 154-160 form an unstructured coil which adopts a substructure similar to dystrophin residues 240-246 in the carboxyl-terminal portion of the CH2 domain. This region wraps around the stretch of residues that would be equivalent to the proposed actin-binding site ABS1 and ABS2 from dystrophin. This distinctive feature is absent from previously published CH-domain structures. Another feature revealed by comparing the two derivatives is the presence of two loop conformations between Tyr92 and Arg99.

MeSH terms

  • Binding Sites
  • Bromine / pharmacology
  • Calcium-Binding Proteins / chemistry*
  • Calponins
  • Cell Cycle Proteins / chemistry*
  • Cell Cycle Proteins / metabolism*
  • Crystallography, X-Ray
  • GTPase-Activating Proteins / chemistry*
  • GTPase-Activating Proteins / metabolism*
  • Mercury / pharmacology
  • Microfilament Proteins
  • Models, Molecular
  • Protein Conformation
  • Schizosaccharomyces / chemistry*
  • Schizosaccharomyces pombe Proteins / chemistry*
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Sequence Homology, Amino Acid*


  • Calcium-Binding Proteins
  • Cell Cycle Proteins
  • GTPase-Activating Proteins
  • Microfilament Proteins
  • Rng2 protein, S pombe
  • Schizosaccharomyces pombe Proteins
  • Mercury
  • Bromine

Associated data

  • PDB/1P2X
  • PDB/1P5S