Creatine Kinase: Difference between revisions

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Student, David Canner, Michal Harel, Alexander Berchansky

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-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.
+<StructureSection load='1crk' size='350' side='right' scene='34/345515/Cv/1' caption='Crystal Structure of mitochondrial Creatine Kinase complex with phosphate [[1crk]]'>
+__TOC__
+== Function ==
+[[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.
+== Relevance ==
+CK is assayed in blood tests for detection of heart attack, severe muscle breakdown, muscular dystrophy and acute renal failure.
+== Structural highlights ==
+<scene name='34/345515/Cv/1'>The biological asembly of mitochondrial Creatine Kinase is homooctamer</scene>. 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.<ref>PMID:8692275</ref>
 This <scene name='Sandbox26/Beta_sheet/1'>view</scene> shows the beta sheets in black. This <scene name='Sandbox26/Alpha_helices/1'>view</scene> shows the alpha helices in blue. This <scene name='Sandbox26/Amphipathic/2'>view</scene> shows the amphipathic alpha helix element along the surface of the protein in pink in a single subunit.
+==3D structures of creatine kinase==
+[[Creatine kinase 3D structures]]
-<applet load='1crk' size='300' frame='true' align='right' caption='Insert caption here' />
+</StructureSection>
-Reference: Fritz-Wolf K, Schnyder T, Wallimann T, Kabsch W Structure of mitochondrial creatine kinase. Nature. 1996 May 23;381(6580):341-5.
+== References ==
+<references/>
+[[Category:Topic Page]]