title: The crystal structure of a hyper-thermophilic carboxylesterase from the archaeon Archaeoglobus fulgidus.
abstract: The crystal structure of AFEST, a novel hyper-thermophilic carboxylesterase from the archaeon Archaeoglobus fulgidus, complexed with a sulphonyl derivative, has been determined and refined to 2.2 A resolution. This enzyme, which has recently been classified as a member of the hormone- sensitive-lipase (H) group of the esterase/lipase superfamily, presents a canonical alpha/beta hydrolase core, shielded on the C-terminal side by a cap region composed of five alpha-helices. It contains the catalytic triad Ser160, His285 and Asp255, whereby the nucleophile is covalently modified and the oxyanion hole formed by Gly88, Gly89 and Ala161. A structural comparison of AFEST with its mesophilic and thermophilic homologues, Brefeldin A esterase from Bacillus subtilis (BFAE) and EST2 from Alicyclobacillus acidocaldarius, reveals an increase in the number of intramolecular ion pairs and secondary structure content, as well as a significant reduction in loop extensions and ratio of hydrophobic to charged surface area. The variety of structural differences suggests possible strategies for thermostabilization of lipases and esterases with potential industrial applications.
authors.affiliation: Centro di Studio di Biocristallografia- CNR, University of Naples "Federico II", via Mezzocannone 6/8, Naples, 80134, Italy.
authors.forename: G
authors.initials: G
authors.lastname: De Simone
authors.forename: V
authors.initials: V
authors.lastname: Menchise
authors.forename: G
authors.initials: G
authors.lastname: Manco
authors.forename: L
authors.initials: L
authors.lastname: Mandrich
authors.forename: N
authors.initials: N
authors.lastname: Sorrentino
authors.forename: D
authors.initials: D
authors.lastname: Lang
authors.forename: M
authors.initials: M
authors.lastname: Rossi
authors.forename: C
authors.initials: C
authors.lastname: Pedone
mesh_terms: D000595:Amino Acid Sequence; D019611:Archaeoglobus fulgidus / Q000201:enzymology* / Q000235:genetics; D001412:Bacillus subtilis / Q000201:enzymology; D001665:Binding Sites; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D019281:Dimerization; D004795:Enzyme Stability; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D002265:Carboxylic Ester Hydrolases; C085832:brefeldin A esterase; D043182:Carboxylesterase