title: The partially unfolded state of beta-momorcharin characterized with steady-state and time-resolved fluorescence studies.
abstract: The specific conformation of partially unfolded state of beta-momorcharin was characterized through the steady-state and time-resolved fluorescence spectroscopic studies on a single Trp-190 which located adjacently to the active site. The content of secondary structure was retained, the binding of ANS was remarkably enhanced, and the correlation time of entire protein rotation was prolonged at the partially unfolded state formed by being equilibrated with the mild concentration of guanidine hydrochloride. The time-resolved fluorescence depolarization and excitation energy transfer analysis suggest that Trp-190 approached 2 A closer to Tyr-70 and was hidden from the exposure to the protein surface, while the rotational correlation time and freedom of its segmental motion were shortened and enhanced, respectively. These results suggest that the transient folding/unfolding intermediate state of beta-momorcharin adopt the specific conformation at the vicinity of the active site, although it exhibits very similar properties with those of the generally known molten-globule state.
authors.affiliation: Institute of Biophysics, Faculty of Agriculture, Graduate School of Kyushu University, Higashiku, Fukuoka 812-8581, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Fukunaga
authors.forename: Etsuko
authors.initials: E
authors.lastname: Nishimoto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yamashita
authors.forename: Takuhiro
authors.initials: T
authors.lastname: Otosu
authors.forename: Shoji
authors.initials: S
authors.lastname: Yamashita
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D002942:Circular Dichroism; D005454:Fluorescence Polarization; D019791:Guanidine / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012269:Ribosomal Proteins / Q000737:chemistry*; D054788:Ribosome Inactivating Proteins; D013050:Spectrometry, Fluorescence
chemical_list: D000817:Anilino Naphthalenesulfonates; D010940:Plant Proteins; D012269:Ribosomal Proteins; C027132:1-anilino-8-naphthalenesulfonate; C039582:MMC protein, Momordica charantia; D054788:Ribosome Inactivating Proteins; D019791:Guanidine