title: Identification and characterization of molten globule-like state of hen egg-white lysozyme in presence of salts under alkaline conditions.
abstract: In the present study, we elucidated the effect of potassium salts on alkali denatured hen egg white lysozyme (EC 3.2.1.17) using intrinsic/extrinsic fluorescence as well circular dichroism (CD) spectroscopic methods. Intrinsic fluorescence studies revealed that various potassium salts mediate stabilization of lysozyme against alkali denaturation. Far and near UV CD spectrum studies, showed that 2M KCl induced appreciable amount of secondary structure with minimum tertiary contacts in lysozyme at pH 12.6. Acrylamide quenching studies suggest that at pH 12.6, the presence of 2M KCl causes reduced accessibility of the quencher to tryptophan residues of the protein presumably because of its compact conformation. In summary, the results of present study suggest that lysozyme attains a compact folded intermediate with molten globule like characteristics at alkaline pH in presence of potassium chloride.
authors.affiliation: Inter-disciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India.
authors.forename: M A
authors.initials: MA
authors.lastname: Ansari
authors.forename: S
authors.initials: S
authors.lastname: Zubair
authors.forename: S M
authors.initials: SM
authors.lastname: Atif
authors.forename: M
authors.initials: M
authors.lastname: Kashif
authors.forename: N
authors.initials: N
authors.lastname: Khan
authors.forename: M
authors.initials: M
authors.lastname: Rehan
authors.forename: T
authors.initials: T
authors.lastname: Anwar
authors.forename: A
authors.initials: A
authors.lastname: Iqbal
authors.forename: M
authors.initials: M
authors.lastname: Owais
mesh_terms: D020106:Acrylamide / Q000737:chemistry; D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011189:Potassium Chloride / Q000737:chemistry; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012492:Salts / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry
chemical_list: D012492:Salts; D020106:Acrylamide; D011189:Potassium Chloride; D014364:Tryptophan; D009113:Muramidase