The structure of rice weevil pectin methylesterase.
Rice weevils (Sitophilus oryzae) use a pectin methylesterase (EC 3.1.1.11), along with other enzymes, to digest cell walls in cereal grains. The enzyme is a right-handed β-helix protein, but is circularly permuted relative to plant and bacterial pectin methylesterases, as shown by the crystal structure determination reported here. This is the first structure of an animal pectin methylesterase. Diffraction data were collected to 1.8 Å resolution some time ago for this crystal form, but structure solution required the use of molecular-replacement techniques that have been developed and similar structures that have been deposited in the last 15 years. Comparison of the structure of the rice weevil pectin methylesterase with that from Dickeya dandantii (formerly Erwinia chrysanthemi) indicates that the reaction mechanisms are the same for the insect, plant and bacterial pectin methylesterases. The similarity of the structure of the rice weevil enzyme to the Escherichia coli lipoprotein YbhC suggests that the evolutionary origin of the rice weevil enzyme was a bacterial lipoprotein, the gene for which was transferred to a primitive ancestor of modern weevils and other Curculionidae. Structural comparison of the rice weevil pectin methylesterase with plant and bacterial enzymes demonstrates that the rice weevil protein is circularly permuted relative to the plant and bacterial molecules.
Department of Biochemistry, University of Washington, Box 357430, Seattle, WA 98195-7430, USA.
David C
DC
Teller
Department of Biochemistry, University of Washington, Box 357430, Seattle, WA 98195-7430, USA.
Craig A
CA
Behnke
Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.
Kirk
K
Pappan
Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.
Zicheng
Z
Shen
Department of Entomology, Kansas State University, Manhattan, KS 66506, USA.
John C
JC
Reese
Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.
Gerald R
GR
Reeck
Department of Biochemistry, University of Washington, Box 357430, Seattle, WA 98195-7430, USA.
Ronald E
RE
Stenkamp
D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry*; D012275:Oryza / Q000201:enzymology*; D017433:Protein Structure, Secondary; D048889:Weevils; D014961:X-Ray Diffraction
D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
Sitophilus oryzae; pectin methylesterase; rice weevil