Fluorescence studies on the role of tryptophan in heterogeneous nuclear ribonucleoprotein particles of HeLa cells.
The 40 S heterogeneous nuclear ribonucleoprotein (hnRNP) particles from HeLa cells reveal tryptophan fluorescence with a bi-exponential decay, indicating that only a few of the 'core' proteins contain tryptophan residues. The presence of tryptophan residues distinguishes hnRNP particles from nucleosomes, with which they otherwise share a number of properties. This difference, however, is not essential for protein-RNA binding, as the fluorescence decay remains unchanged when hnRNP particles are dissociated into protein and RNA. However, the Stern-Volmer quenching constant is doubled upon salt dissociation, i.e. tryptophan residues become more accessible to solvent. Thus tryptophan quenching is a useful parameter for monitoring protein-protein interactions in hnRNP particles.
Schenkel
J
J
Molekulare Genetik der Universität Heidelberg, Federal Republic of Germany.
Appel
I
I
Schwarzwald
R
R
Bautz
E k
Ek
Wolfrum
J
J
Greulich
K O
KO
D002467:Cell Nucleus / Q000378:metabolism; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D009994:Osmolar Concentration; D012261:Ribonucleoproteins / Q000378:metabolism*; D012965:Sodium Chloride; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism*
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins; D012965:Sodium Chloride; D014364:Tryptophan