%A Xiaoyan Zhao, Hai Pang, Shenglan Wang, Keqian Yang, Weihong Zhou, Mark Bartlam, %T Structural basis for prokaryotic calcium- mediated regulation by a Streptomyces coelicolor calcium binding protein %0 Journal Article %D 2010 %J Protein Cell %J Protein & Cell %@ 1674-800X %R 10.1007/s13238-010-0085-z %P 771-779 %V 1 %N 8 %U {https://journal.hep.com.cn/pac/EN/10.1007/s13238-010-0085-z %8 2010-08-01 %X The important and diverse regulatory roles of Ca2+ in eukaryotes are conveyed by the EF-hand containing calmodulin superfamily. However, the calcium-regulatory proteins in prokaryotes are still poorly understood. In this study, we report the three-dimensional structure of the calcium-binding protein from Streptomyces coelicolor, named CabD, which shares low sequence homology with other known helix-loop-helix EF-hand proteins. The CabD structure should provide insights into the biological role of the prokaryotic calcium-binding proteins. The unusual structural features of CabD compared with prokaryotic EF-hand proteins and eukaryotic sarcoplasmic calcium-binding proteins, including the bending conformation of the first C-terminal α-helix, unpaired ligand-binding EF-hands and the lack of the extreme C-terminal loop region, suggest it may have a distinct and significant function in calcium-mediated bacterial physiological processes, and provide a structural basis for potential calcium-mediated regulatory roles in prokaryotes.