Conformational changes at the nucleotide binding of GroEL induced by binding of protein substrates. Luminescence studies.
2'-Deoxy-3'-anthraniloyl adenosine-5-triphosphate (ANT-dATP) coordinated to Tb3+ was used as an environmentally sensitive probe of the nucleotide-binding site of GroEL. Tb3+.ANT-dATP recognizes the nucleotide-binding site of GroEL and inhibits ATPase activity. Sensitized luminescence, arising from resonance energy transfer from the anthraniloyl moiety to Tb3+, is substantially enhanced in the presence of GroEL. Binding of denatured mitochondrial malate dehydrogenase to the apical domain of GroEL causes a red shift in the fluorescence emitted by anthraniloyl and further enhancement in the phosphorescence emitted by Tb3+ upon excitation at 320 nm. It is suggested that binding of the protein substrate initiates domain movement, which is extended to the nucleotide-binding site. The luminescence results are discussed in reference to the structure of GroEL derived from x-ray crystallographic studies.
Churchich
J E
JE
Department of Biochemistry, University of Tennessee, Knoxville, Tennessee 37996-0840, USA.
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D001665:Binding Sites; D018834:Chaperonin 60 / Q000378:metabolism*; D004926:Escherichia coli; D005456:Fluorescent Dyes / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013725:Terbium / Q000378:metabolism; D062367:ortho-Aminobenzoates / Q000378:metabolism
D018834:Chaperonin 60; D005456:Fluorescent Dyes; D062367:ortho-Aminobenzoates; D013725:Terbium; C066294:3'-anthraniloyl-2'-deoxy-ATP; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase