The Changes of Isoform Composition, Structure and Functional Properties of Cardiac Muscle Titin of Mongolian Gerbil (Meriones unguiculatus) after Space Flight
The study on changes of isoform composition, secondary structure, degree of phosphorylation of titin in cardiac muscle of mongolian gerbils (<i>Meriones unguiculatus</i>) after 12-day space flight onboard the Russian Space capsule Foton-M3 was carried out. The effect of titin on actin!activated activity of myosin at pCa 7,5 and 4,6 was studied. By the use of low-percentage SDS-PAGE and Western blotting the twofold increase of N2BA:N2B-protein ratio in left ventricle of cardiac muscle of space flight gerbils was detected. The changes of secondary structure and increase (by ~1,3-1,35 times) of inorganic phosphate content in cardiac muscle titin of space flight gerbils in comparison with those characteristics of cardiac musсle titin of control animals were revealed. The decrease of activating influence of cardiac muscle titin of space flight gerbils on actin!activated ATPase activity of actomyosin was observed. The changes observed are discussed in the context of adaptation of cardiac muscle of mongolian gerbils to conditions of real microgravity.