3aik

Publication Abstract from PubMed

The hormone-sensitive lipase (HSL) family is comprised of carboxylesterases and lipases with similarity to mammalian HSL. Thermophilic enzymes of this family have a high potential for use in biocatalysis. We prepared and crystallized a carboxylesterase of the HSL family from Sulfolobus tokodaii (Sto-Est), and determined its structures in the presence and absence of an inhibitor. Sto-Est forms a dimer in solution and the crystal structure suggests the presence of a stable biological dimer. We identified a residue close to the dimer interface, R267, which is conserved in archaeal enzymes of HSL family and is in close proximity to the same residue from the other monomer. Mutations of R267 to Glu, Gly and Lys were conducted and the resultant R267 mutants were characterized and crystallized. The structures of R267E, R267G and R267K are highly similar to that of Sto-Est with only slight differences in atomic coordinates. The dimerized states of R267E and R267G are unstable under denaturing conditions or at high temperature, as shown by a urea-induced dimer dissociation experiment and molecular dynamics simulation. R267E is the most unstable mutant protein, followed by R267G and R267K, as shown by the thermal denaturation curve and optimum temperature for activity. From the data, we discuss the importance of R267 in maintaining the dimer integrity of Sto-Est. Database The atomic coordinates and structural factors have been deposited in the Protein Data Bank with accession numbers of PDB: 3AIK for noninhibited Sto-Est, PDB: 3AIL for DEP-bound, PDB: 3AIM for R267E, PDB: 3AIN for R267G, and PDB: 3AIO for R267K Structured digital abstract * Sto-Es and Sto-Es bind by comigration in gel electrophoresis (View Interaction: 1, 2) * Sto-Es and Sto-Es bind by x-ray crystallography (View interaction).

Structure and stability of a thermostable carboxylesterase from the thermoacidophilic archaeon Sulfolobus tokodaii.,Angkawidjaja C, Koga Y, Takano K, Kanaya S FEBS J. 2012 Sep;279(17):3071-84. doi: 10.1111/j.1742-4658.2012.08687.x. Epub, 2012 Jul 23. PMID:22748144^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.