title: Adenylate kinase from Sulfolobus acidocaldarius: expression in Escherichia coli and characterization by Fourier transform infrared spectroscopy.
abstract: Adenylate kinase from the extremely thermoacidophilic archaeon Sulfolobus acidocaldarius has been overexpressed in Escherichia coli. The highly purified enzyme was characterized by Fourier transform infrared spectroscopy (FTIR). Analysis of FTIR spectra and estimation of secondary structure revealed a global protein structure similar to that of other adenylate kinases. Thermal unfolding of the protein with an estimated Tm value near 90 degrees C is irreversible due to protein aggregation. The enzyme exhibits long-term stability up to 80 degrees C, which is an excellent adaptation to the physiological growth temperature of 75-80 degrees C. Half-widths of secondary-structure-sensitive bands and hydrogen-deuterium exchange experiments revealed that in comparison to adenylate kinase from porcine muscle cytosol the Sulfolobus enzyme is characterized by a significantly more compact and rigid protein core structure, which is likely to contribute specifically to the extreme thermostability of the protein.
authors.affiliation: Institute of Biochemistry, Medical University of Lübeck, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Bönisch
authors.forename: J
authors.initials: J
authors.lastname: Backmann
authors.forename: T
authors.initials: T
authors.lastname: Kath
authors.forename: D
authors.initials: D
authors.lastname: Naumann
authors.forename: G
authors.initials: G
authors.lastname: Schäfer
mesh_terms: D000263:Adenylate Kinase / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D000818:Animals; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D003903:Deuterium; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D006860:Hydrogen Bonding; D015394:Molecular Structure; D017433:Protein Structure, Secondary; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D016945:Sulfolobus acidocaldarius / Q000201:enzymology* / Q000235:genetics*; D013552:Swine; D013696:Temperature
chemical_list: D003903:Deuterium; D000263:Adenylate Kinase