title: A highly thermostable trehalase from the thermophilic bacterium Rhodothermus marinus.
abstract: Trehalases play a central role in the metabolism of trehalose and can be found in a wide variety of organisms. A periplasmic trehalase (alpha,alpha-trehalose glucohydrolase, EC 3.2.1.28) from the thermophilic bacterium Rhodothermus marinus was purified and the respective encoding gene was identified, cloned and overexpressed in Escherichia coli. The recombinant trehalase is a monomeric protein with a molecular mass of 59 kDa. Maximum activity was observed at 88 degrees C and pH 6.5. The recombinant trehalase exhibited a K(m) of 0.16 mM and a V(max) of 81 micromol of trehalose (min)(-1) (mg of protein)(-1) at the optimal temperature for growth of R. marinus (65 degrees C) and pH 6.5. The enzyme was highly specific for trehalose and was inhibited by glucose with a K(i) of 7 mM. This is the most thermostable trehalase ever characterized. Moreover, this is the first report on the identification and characterization of a trehalase from a thermophilic bacterium.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Apartado 127, 2780-156, Oeiras, Portugal.
authors.forename: Carla D
authors.initials: CD
authors.lastname: Jorge
authors.forename: Maria Manuel
authors.initials: MM
authors.lastname: Sampaio
authors.forename: Gudmundur O
authors.initials: GO
authors.lastname: Hreggvidsson
authors.forename: Jakob K
authors.initials: JK
authors.lastname: Kristjánson
authors.forename: Helena
authors.initials: H
authors.lastname: Santos
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D030562:Databases, Protein; D004795:Enzyme Stability; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D033903:Periplasmic Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000378:metabolism; D045245:Rhodothermus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014198:Trehalase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014199:Trehalose / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D033903:Periplasmic Proteins; D011994:Recombinant Proteins; D014199:Trehalose; D014198:Trehalase; D005947:Glucose