Sequence analysis suggests the presence of an IG-like domain in the N-terminal region of alpha-dystroglycan which was crystallized after mutation of a protease susceptible site (Arg(168)-> His)
D. Bozic et al., Sequence analysis suggests the presence of an IG-like domain in the N-terminal region of alpha-dystroglycan which was crystallized after mutation of a protease susceptible site (Arg(168)-> His), MATRIX BIOL, 17(7), 1998, pp. 495-500
Recently, we demonstrated that the N-terminal region of mouse alpha-dystrog
lycan represents an autonomously folding globular domain, organized into at
least two subdomains (Brancaccio et al., fur. J. Biochem. 246, 166-172, 19
97). We have now found a similarity between a part of the alpha-dystroglyca
n N-terminal sequence (approximately from position 80 to 180) and several p
rotein sequences belonging to the immunoglobulin kappa family. Moreover, we
have recombinantly expressed and purified a 31 kDa protein fragment which
matches the entire alpha-dystroglycan N-terminal globular domain. To preven
t the action of bacterial endogenous proteases and/or thrombin, which cleav
es the protein into two fragments at an Arg-Ala trypsin-sensitive site in p
ositions 168-169, we have introduced a single mutation (Arg(168) --> His),
thus making the whole domain more stable and suitable for crystallization.
Crystals of this mutant protein were obtained by vapor diffusion using the
hanging drop technique, and they diffract to 0.28 nm Bragg spacing.