ABSTRACT

The purpose of this chapter is to describe a number of proteins that bind copper but that cannot readily be classified with the family of proteins that are involved in the transport and activation of dioxygen (Chapter 15) or the multicopper oxidases (Chapter 16). Such proteins include albumin, copper-zinc superoxide dismutase (SOD), the metallothioneins, and Menkes’ copper-transporting ATPases. In the case of albumin and SOD, single-crystal X-ray structures have been determined. In addition, for SOD extensive NMR studies have been undertaken (e.g., [1]). For Menkes’ Cu-transporting ATPases and the Cu-binding metallothioneins the struc­ tures have been determined only by NMR methods. NMR techniques normally pro­ duce a batch of similar structures distributed in space around a common framework, so that the structural information is not as precise as that determined by high-resolu­ tion X-ray methods. This lack of precision is adequately compensated by the applica­ tion of such methods to solutions of macromolecules, obviating the need to grow single crystals of a quality suitable for the X-ray technique. In addition, NMR tech­ niques can be readily adapted to studying molecular flexibility and the dynamics of reaction mechanisms.