Prodan fluorescence mimics the GroEL folding cycle.
The non-covalent fluorescent probe 6-propionyl-2-(dimethylamino) naphthalene sulfonate (prodan) binds to hydrophobic surfaces exposed on the surface of GroEL. Under identical experimental conditions free prodan exhibits a green emission peak of intensity 390,000 cps at 520 nm. However prodan bound to GroEL, GroEL-ATP, and GroEL-ATP-GroES shows emission peaks of intensities 500,000, 540,000, and 480,000 cps at 515, 512 and 515 nm, respectively, thus mimicing the way hydrophobic surfaces on GroEL become exposed during the folding cycle. Other hydrophobic probes like bis-ANS and dansyl lysine were unable to detect the minor changes in hydrophobic exposure of GroEL after it binds to ATP, although they were able to detect hydrophobic exposure in GroEL itself.
Kaur
Yogeet
Y
Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA.
Horowitz
Paul M
PM
D015081:2-Naphthylamine / Q000031:analogs & derivatives*; D001426:Bacterial Proteins / Q000737:chemistry*; D018833:Chaperonins; D029968:Escherichia coli Proteins; D005456:Fluorescent Dyes; D006360:Heat-Shock Proteins / Q000737:chemistry*; D017510:Protein Folding; D013050:Spectrometry, Fluorescence
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D005456:Fluorescent Dyes; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; C038517:prodan; D015081:2-Naphthylamine; D018833:Chaperonins