Introduction

Abstract

The subject of myofilament structure, introduced in the following four contributions, appears as a recurring theme throughout this volume. This is not surprising, since this topic is intimately related to our understanding of the crossbridge mechanism in muscle contraction. What may be surprising, however, is the current reinvestigation, with improved methodology, of such aspects of myofilament structure as filament dimensions and the three-dimensional geometry of the S-1-thin filament complex, which, only recently were considered to be well established. Here, these issues share the podium with such acknowledged unsolved problems as the packing of component myosin molecules within the thick filaments and the nature of the constraints on freedom of crossbridge movement within the overlap zone of the filament lattice.