Lens Proteins and the systematic position of the musophagiformes and cuculiformes

Résumé La micro-électrophorèse en agargel des protéines solubles de la lentille deTuracus a donné un phérogramme assez analogue à celui des Passeriformes. Aussi la présence de glycogène dans la lentille semble démontrer que les touracous doivent Être classés parmi les ordres aviaires les plus évolués et non pas près des Galliformes.     

Structure of the actin-myosin interface

The topography of the rigor complex between F-actin and myosin heads (S1) has been investigated by carbodiimide zero-length cross-linking. The results demonstrate for the first time that the 95,000-molecular weight (95K) heavy chain of the myosin head enters into van der Waals contact with two neighbouring actin monomers; one is bound to the 50K domain and the other to the 20K domain of the myosin chain. The covalent F-actin-S1 complex can be isolated; it shows a vastly elevated Mg2+-ATPase. Each pair of actin subunits in the thin filament seems to act as a functional unit for specific binding of a myosin head and stimulation of its Mg2+-ATPase activity.