1s6j
From Proteopedia
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N-terminal Region of the Ca2+-saturated calcium regulatory domain (CLD) from Soybean Calcium-dependent Protein Kinase-alpha (CDPK)
Overview
Ca(2+)-dependent protein kinases (CDPKs) are vital Ca(2+)-signaling, proteins in plants and protists which have both a kinase domain and a, self-contained calcium regulatory calmodulin-like domain (CLD). Despite, being very similar to CaM (>40% identity) and sharing the same fold, recent biochemical and structural evidence suggests that the behavior of, CLD is distinct from its namesake, calmodulin. In this study, NMR, spectroscopy is employed to examine the structure and backbone dynamics of, a 168 amino acid Ca(2+)-saturated construct of the CLD (NtH-CLD) in which, almost the entire C-terminal domain is exchange broadened and not visible, in the NMR spectra. Structural characterization of the N-terminal domain, indicates that the first Ca(2+)-binding loop is significantly more open, than in a recently reported structure of the CLD complexed with a putative, intramolecular binding region (JD) in the CDPK. Backbone dynamics suggest, that parts of the third helix exhibit unusually high mobility, and, significant exchange, consistent with previous findings that this helix, interacts with the C-terminal domain. Dynamics data also show that the, "tether" region, consisting of the first 11 amino acids of CLD, is highly, mobile and these residues exhibit distinctive beta-type secondary, structure, which may help to position the JD and CLD. Finally, the unusual, global dynamic behavior of the protein is rationalized on the basis of, possible interdomain rearrangements and the highly variable environments, of the C- and N-terminal domains.
About this Structure
1S6J is a Single protein structure of sequence from Glycine max with as ligand. Full crystallographic information is available from OCA.
Reference
Solution structure and backbone dynamics of the N-terminal region of the calcium regulatory domain from soybean calcium-dependent protein kinase alpha., Weljie AM, Gagne SM, Vogel HJ, Biochemistry. 2004 Dec 7;43(48):15131-40. PMID:15568805
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