The only published class II aldolase structure is reported at high resolution in two forms, with a zinc ion and with a cobalt ion in the active center. An irregular birefringence along the fourfold axis indicates slight rearrangements of the N-terminal domain that contains the active center.

The C₄-tetrameric enzyme crystallized with 20 protomers in the asymmetric unit. The atomic cstructure was solved using one heavy-atom derivative at 6 Å resolution and the molecular envelope of a related enzyme.

A designed mutant of the enzyme glutathione reductase, consisting of two point mutations, shortens the crystallization time by a factor of forty, most probably by facilitating nucleation.

Rat ecto-ADP-ribosyltransferase (ART2.2) has been expressed in the periplasm of E. coli, purified and crystallized in three forms diffracting to high resolution.

Proper NCS rotation axes can be identified and located in surprisingly poor electron-density maps. The described program performs an overall search using reasonable computing time.

Three protein crystal forms are described that appear to grow from fibers. One fiber type forms sheets that aggregate readily with low symmetry, but can be forced by an inter-protein bond to a highly symmetric association. In one case the fiber introduces an exact twofold screw axis that is infinite but non-crystallographic.