CONFORMATIONAL DYNAMICS AND ENZYME-ACTIVITY

Conformational flexibility and structural fluctuations play an importa nt role in enzyme activity. A great variety of internal motions rangin g over different rime scales and of different amplitudes are involved in the catalytic cycle. These different types of motions and their fun ctional consequences are considered in the light of experimental data and theoretical analyses. The conformational changes upon substrate bi nding, and particularly the hinge-bending motion which occurs in enzym es made of two domains, are analyzed from several well documented exam ples. The conformational events accompanying the different steps of th e catalytic cycle are discussed. The last section concerns the motions involved in the allosteric transition which regulates the enzyme acti vity. ((C) Societe francaise de biochimie et biologie moleculaire/Else vier, Paris).