tailieunhanh - Báo cáo khoa học: Origin and properties of cytoplasmic and mitochondrial isoforms of taurocyamine kinase

Taurocyamine kinase (TK) is a member of the highly conserved family of phosphagen kinases that includes creatine kinase (CK) and arginine kinase. TK is found only in certain marine annelids. In this study we used PCR to amplify two cDNAs coding for TKs from the polychaeteArenicola brasil-iensis, cloned these cDNAs into the pMAL plasmid and expressed the TKs as fusion proteins with the maltose-binding protein. | ềFEBS Journal Origin and properties of cytoplasmic and mitochondrial isoforms of taurocyamine kinase Kouji Uda1 Naoto Saishoji1 Shuichi Ichinari1 W. Ross Ellington2 and Tomohiko Suzuki1 1 Laboratory of Biochemistry Faculty of Science Kochi University Japan 2 Institute of Molecular Biophysics and Department of BiologicalScience Florida State University Tallahassee FL USA Keywords taurocyamine kinase creatine kinase phosphagen kinase cDNA sequence mitochondrial Correspondence T. Suzuki Laboratory of Biochemistry Faculty of Science Kochi University Kochi 780-8520 Japan Fax 81 88 844 8356 Tel 81 88 844 8693 E-mail suzuki@ Received 9 March 2005 revised 23 April 2005 accepted 13 May 2005 doi Taurocyamine kinase TK is a member of the highly conserved family of phosphagen kinases that includes creatine kinase CK and arginine kinase. TK is found only in certain marine annelids. In this study we used PCR to amplify two cDNAs coding for TKs from the polychaete Arenicola brasil-iensis cloned these cDNAs into the pMAL plasmid and expressed the TKs as fusion proteins with the maltose-binding protein. These are the first TK cDNA and deduced amino acid sequences to be reported. One of the two cDNA-derived amino acid sequences of TKs shows a high amino acid identity to lombricine kinase another phosphagen kinase unique to annelids and appears to be a cytoplasmic isoform. The other sequence appears to be a mitochondrial isoform it has a long N-terminal extension that was judged to be a mitochondrial targeting peptide by several on-line programs and shows a higher similarity in amino acid sequence to mitochondrial creatine kinases from both vertebrates and invertebrates. The recombinant cytoplasmic TK showed activity for the substrates taurocyamine and lombricine 9 of that of taurocyamine . However the mitochondrial TK showed activity for taurocyamine lombricine 30 of that of taurocyam-ine and glycocyamine 7 of that of taurocyamine . .