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

Academic Article

Abstract

  • 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.
  • Authors

    Keywords

  • Binding Sites, Bromine, Calcium-Binding Proteins, Cell Cycle Proteins, Crystallography, X-Ray, GTPase-Activating Proteins, Mercury, Microfilament Proteins, Models, Molecular, Protein Conformation, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, Sequence Homology, Amino Acid
  • Digital Object Identifier (doi)

    Author List

  • Wang C-H; Balasubramanian MK; Dokland T
  • Start Page

  • 1396
  • End Page

  • 1403
  • Volume

  • 60
  • Issue

  • Pt 8