FUNCTIONAL-ASPECTS OF THE X-RAY STRUCTURE OF MITOCHONDRIAL CREATINE-KINASE - A MOLECULAR PHYSIOLOGY APPROACH

Mitochondrial creatine kinase (Mi-CK) is a central enzyme in energy me tabolism of tissues with high and fluctuating energy requirements. In this review, recent progress in the functional and structural characte rization of Mi-CK is summarized with special emphasis on the solved X- ray structure of chicken Mi(b)-CK octamer (Fritz-Wolf et al., Nature 3 81, 341-345, 1996). The new results are discussed in a historical cont ext and related to the characteristics of CK isoforms as known from a large number of biophysical and biochemical studies. Finally, two hypo thetical functional aspects of the Mi-CK structure are proposed: (i) p utative membrane binding motifs at the top and bottom faces of the oct amer and (ii) a possible functional role of the central 20 Angstrom ch annel.