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Expression and biochemical characterization of two small heat shock proteins from the thermoacidophilic crenarchaeon Sulfolobus tokodaii strain 7
Author(s) -
Usui Keisuke,
Ishii Noriyuki,
Kawarabayasi Yutaka,
Yohda Masafumi
Publication year - 2004
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.03264204
Subject(s) - sulfolobus , thermophile , biology , chaperone (clinical) , biochemistry , protein subunit , biophysics , enzyme , archaea , medicine , pathology , gene
Abstract We expressed and characterized two sHsps, StHsp19.7 and StHsp14.0, from a thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain 7. StHsp19.7 forms a filamentous structure consisting of spherical particles and lacks molecular chaperone activity. Fractionation of Sulfolobus extracts by size exclusion chromatography with immunoblotting indicates that StHsp19.7 exists as a filamentous structure in vivo. On the other hand, StHsp14.0 exists as a spherical oligomer like other sHsps. It showed molecular chaperone activity to protect thermophilic 3‐isopropylmalate dehydrogenase (IPMDH) from thermal aggregation at 87°C. StHsp14.0 formed variable‐sized complexes with denatured IPMDH at 90°C. Using StHsp14.0 labeled with fluorescence or biotin probe and magnetic separation, subunit exchanges between complexes were demonstrated. This is the first report on the filament formation of sHsp and also the high molecular chaperone activity of thermophilic archaeal sHsps.