1oqp
From Proteopedia
STRUCTURE OF THE CA2+/C-TERMINAL DOMAIN OF CALTRACTIN IN COMPLEX WITH THE CDC31P-BINDING DOMAIN FROM KAR1P
Structural highlights
Function[CATR_CHLRE] This calcium-binding protein is found in the basal body complexes (the functional homolog of the centrosome in animal cell). In mitotic cells it is specifically associated with the poles of the mitotic spindles at the sites of the duplicated basal body complexes. [KAR1_YEAST] KAR1 is required for function of both intranuclear and extranuclear microtubules. KAR1 helps localize CDC31 to the spindle pole body (SPB), CDC31 then initiates SPB duplication via interaction with a downstream effector.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCaltractin (centrin) is a member of the calmodulin (CaM) superfamily of EF-hand calcium-binding proteins. It is an essential component of the centrosomal structures in a wide range of organisms. Caltractin and calmodulin apparently function in distinct calcium signaling pathways despite substantial sequence similarity. In an effort to understand the structural basis for such differences, the high-resolution three-dimensional solution structure of the complex between the Ca(2+)-activated C-terminal domain of Chlamydomonas reinhardtii caltractin (CRC-C) and a 19 residue peptide fragment comprising the putative cdc31p-binding region of Kar1p (K(19)) has been determined by multi-dimensional heteronuclear NMR spectroscopy. Formation of the complex is calcium-dependent and is stabilized by extensive interactions between CRC-C and three key hydrophobic anchors (Trp10, Leu13 and Leu14) in the peptide as well as favorable electrostatic interactions at the protein-peptide interface. In-depth comparisons have been made to the structure of the complex of Ca(2+)-activated calmodulin and R(20), the CaM-binding domain of smooth muscle myosin light-chain kinase. Although the overall structures of CRC and CaM domains in their respective complexes are very similar, differences in critical regions in the sequences of these proteins and their targets lead to clear differences in the complementarity of their respective binding surfaces. These subtle differences reveal the structural basis for the Ca(2+)-dependent regulation of distinct cellular signaling events by CRC and CaM. Unique features in the C-terminal domain provide caltractin with target specificity.,Hu H, Chazin WJ J Mol Biol. 2003 Jul 11;330(3):473-84. PMID:12842464[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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