Journal:Acta Cryst F:S1744309112003326

Structure of recombinant human carboxylesterase 1 isolated from whole cabbage looper larvae

Harry M. Greenblatt, Tamara C. Otto, Melanie G. Kirkpatrick, Elena Kovaleva, Susan Brown,George Buchman, Douglas M. Cerasoli and Joel L. Sussman^[1]

Molecular Tour

The use of whole insect larvae as a source of recombinant proteins offers a more cost-effective method of producing large quantities of human proteins than conventional cell-culture approaches. Human carboxylesterase 1 (rhCES1) has been produced in and isolated from whole Trichoplusia ni larvae. The recombinant protein was crystallized and its structure was solved to 2.2 Å resolution. The results indicate that the larvae-produced enzyme is essentially identical to that isolated from cultured Sf21 cells, supporting the use of this expression system to produce recombinant enzymes for crystallization studies.

The current structure of rhCES1 represents the first published hexagonal crystal form, despite the fact that all other published examples of hCES1 structures consist of a hexamer in the asymmetric unit. found in this space group, while the three twofold axes at z = 1/4 that intersect on this axis complete the hexamer.