Abstract
Creatine kinase (CK, EC 2.7.3.2), an enzyme important for energy metabolism in cells of high and fluctuating energy requirements, catalyses the reversible transfer of a phosphoryl goup from phosphocreatine to ADP. We have solved the structure of the octameric mitochondrial isoform, Mib-CK, which is located in the intermembrane compartment and along the cristae membranes. Mib-CK consumes ATP produced in the mitochondria for the production of phosphocreatine, which is then exported into the cytosol for fast regeneration of ATP by the cytosolic CK isoforms. The octamer has 422 point-group symmetry, and appears as a cube of side length 93 angstrom with a channel 20 angstrom wide extending along the four-fold axis. Positively charged amino acids at the four-fold faces of the octamer possibly interact with negatively charged mitochondrial membranes. Each monomer consists of a small alpha-helical domain and a large domain containing an eight-stranded antiparallel beta-sheet flanked by seven alpha-helices. The conserved residues of the CK family form a compact cluster that covers the active site between the domains.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.