title: Fluorescence studies on the role of tryptophan in heterogeneous nuclear ribonucleoprotein particles of HeLa cells.
abstract: 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.
authors.affiliation: Molekulare Genetik der Universität Heidelberg, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schenkel
authors.forename: I
authors.initials: I
authors.lastname: Appel
authors.forename: R
authors.initials: R
authors.lastname: Schwarzwald
authors.forename: E k
authors.initials: Ek
authors.lastname: Bautz
authors.forename: J
authors.initials: J
authors.lastname: Wolfrum
authors.forename: K O
authors.initials: KO
authors.lastname: Greulich
mesh_terms: 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*
chemical_list: D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins; D012965:Sodium Chloride; D014364:Tryptophan