1sdm | pdb_00001sdm
Crystal structure of kinesin-like calmodulin binding protein
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Overview
Kinesins orchestrate cell division by controlling placement of, chromosomes. Kinesins must be precisely regulated or else cell division, fails. Calcium, a universal second messenger in eukaryotes, and calmodulin, regulate some kinesins by causing the motor to dissociate from its, biological track, the microtubule. Our focus was the mechanism of calcium, regulation of kinesin at atomic resolution. Here we report the crystal, structure of kinesin-like calmodulin-binding protein (KCBP) from potato, which was resolved to 2.3 A. The structure reveals three subdomains of the, regulatory machinery located at the C terminus extension of the kinesin, motor. Calmodulin that is activated by Ca2+ ions binds to an alpha-helix, positioned on the microtubule-binding face of kinesin. A negatively, charged segment following this helix competes with microtubules. A mimic, of the conventional kinesin neck, connecting the calmodulin-binding helix, to the KCBP motor core, links the regulatory machine to the kinesin, catalytic cycle. Together with biochemical data, the crystal structure, suggests that Ca(2+)-calmodulin inhibits the binding of KCBP to, microtubules by blocking the microtubule-binding sites on KCBP.
About this Structure
1SDM is a Single protein structure of sequence from Solanum tuberosum with MG and ADP as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of kinesin regulated by Ca(2+)-calmodulin., Vinogradova MV, Reddy VS, Reddy AS, Sablin EP, Fletterick RJ, J Biol Chem. 2004 May 28;279(22):23504-9. Epub 2004 Feb 26. PMID:14988396
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