Purification and structural study of the beta form of human cAMP-dependent protein kinase inhibitor.
The beta form of human cAMP-dependent protein kinase inhibitor (human PKIbeta), a novel heat-stable protein, was isolated with high yield using a bacterial expression system. Assays of PKI activity demonstrated that purified PKIbeta inhibits the catalytic subunit of cAMP-dependent protein kinase. FTIR, Raman spectroscopy and CD experiments implied that human PKIbeta contained only small amounts of alpha-helix and beta-structures, but large amounts of random coil and turn structures, which may explain its high thermostability. The details of its conformational changes in response to heat were studied by CD experiments for the first time, revealing that the protein unfolded at high temperature and refolded when decreased to room temperature.
Jin
Rong
R
Center of Analysis and Measurement, School of Life Sciences, Fudan University, Shanghai, PR China.
Dai
Linsen
L
Zheng
Jinbiao
J
Ji
Chaoneng
C
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D002942:Circular Dichroism; D003001:Cloning, Molecular; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000302:isolation & purification; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; C015482:protein kinase modulator; D017868:Cyclic AMP-Dependent Protein Kinases