Crystal structure of YdaL, a stand-alone small MutS-related protein from Escherichia coli.
Gui, W.J., Qu, Q.H., Chen, Y.Y., Wang, M., Zhang, X.E., Bi, L.J., Jiang, T.(2011) J Struct Biol 174: 282-289
- PubMed: 21276852 
- DOI: https://doi.org/10.1016/j.jsb.2011.01.008
- Primary Citation of Related Structures:  
3QD7 - PubMed Abstract: 
Sequence homologs of the small MutS-related (Smr) domain, the C-terminal endonuclease domain of MutS2, also exist as stand-alone proteins. In this study, we report the crystal structure of a proteolyzed fragment of YdaL (YdaL₃₉-₁₇₅), a stand-alone Smr protein from Escherichia coli. In this structure, residues 86-170 assemble into a classical Smr core domain and are embraced by an N-terminal extension (residues 40-85) with an α/β/α fold. Sequence alignment indicates that the N-terminal extension is conserved among a number of stand-alone Smr proteins, suggesting structural diversity among Smr domains. We also discovered that the DNA binding affinity and endonuclease activity of the truncated YdaL₃₉-₁₇₅ protein were slightly lower than those of full-length YdaL₁-₁₈₇, suggesting that residues 1-38 may be involved in DNA binding.
Organizational Affiliation: 
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China.