Biology Reference
In-Depth Information
as well as to the development of drugs that suppress or enhance the func-
tions of those proteins.
These historical facts, repeatedly advocated by the space agencies of
various countries, tell us at least the following things. First, single protein
crystals and the fine molecular structure obtained by using them are a key
factor in the life sciences of the future. Second, alternative methods of
improving the quality of crystals are not easy to list; space-based experi-
ments have become the primary choice.
The expectations about such experiments may be right. However,
even so, there is good reason to look for alternative, Earth-based methods
of improving crystalline quality. The use of magnetic fields described
below is one such trial. The crystals obtained within magnets may be used
per se for structure determination. The experiments may also be useful in
selecting the best crystals or best crystallization conditions that will ben-
efit from the space-based experiments in the future. The experiments may
elucidate the mechanism by which the microgravity environment in space
leads to quality improvements, thus further justifying investment.
A few reviews are already available on the effects of static, strong
magnetic fields on the quality of protein crystals (Ataka,Wakayama, 2002;
Wakayama, 2003). The topics not covered therein will be dealt with here.
Theoretical Background
Two things must be emphasized when applying a magnetic field to pro-
tein crystal growth.
Magnetic field orientation
First, protein molecules and protein crystals belong magnetically to the cat-
egory of feeble (weak but present) magnetic substances. Feeble magnetic
substances have long been referred to as non-magnetic substances, meaning
that these substances, containing both diamagnetic and paramagnetic mate-
rials, have been considered not to interact with magnetic fields. Instead, fer-
romagnetic materials, including iron, have been the main focus of scientific
research on the use of magnetic fields. It is only somewhat more recently
Search WWH ::




Custom Search