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J Mol Biol. 2005 Dec 16;354(5):1043-51. Epub 2005 Nov 2.

Solution structure of isoform 1 of Roadblock/LC7, a light chain in the dynein complex.

Author information

1
Center for Eukaryotic Structural Genomics, Department of Biochemistry, University of Wisconsin-Madison, WI 53706-1544, USA.

Abstract

Roadblock/LC7 is a member of a class of dynein light chains involved in regulating the function of the dynein complex. We have determined the three-dimensional structure of isoform 1 of the mouse Roadblock/LC7 cytoplasmic dynein light chain (robl1_mouse) by NMR spectroscopy. In contrast to a previously reported NMR structure of the human homolog with 96% sequence identity (PDB 1TGQ), which showed the protein as a monomer, our results indicate clearly that robl1 exists as a symmetric homodimer. The two beta3-strands pair with each other and form a continuous ten-stranded beta-sheet. The 25-residue alpha2-helix from one subunit packs antiparallel to that of the other subunit on the face of the beta-sheet. Zipper-like hydrophobic contacts between the two helices serve to stabilize the dimer. Through an NMR titration experiment, we localized the site on robl1_mouse that interacts with the 40 residue peptide spanning residues 243 through 282 of IC74-1_rat. These results provide physical evidence for a symmetrical interaction between dimeric robl1 and the two molecules of IC74-1 in the dynein complex.

PMID:
16289575
DOI:
10.1016/j.jmb.2005.10.017
[Indexed for MEDLINE]

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