Crystals of "cgHle", an enzyme from Corynebacterium glutamicum with α/β-hydrolase fold and high sequence homology to the family of homoserine acetyltransferases (HAT) (therefore "Hle" = "HAT-like enzyme"). In spite of this homology cgHle itself is no homoserine acetyltransferase. Rather, the physiological role of the enzyme is completely unclear.
The crystallization drops show a phenomenon known as "Ostwald ripening" which is the transition of two crystalline phases in the course of time. From the initially formed spherical aggregates of micro crystals plate-like single crystals start to grow after a while.
CgHle is closely related to the acetylester hydrolase MekB which has a key role in the degradation pathway of methyl ethyl ketones in Pseudomonas veronii. The crystal structures of the two enzymes cgHle and MekB confirm their identity as hydrolases rather than acetyltransferases. Together, cgHle and MekB constitute a new sub-family within the superfamily of α/β-hydrolase fold proteins.