title: Exploring the mechanism of fluorescence quenching in proteins induced by tetracycline.
abstract: The binding of the antibiotic tetracycline hydrochloride (TC) to three proteins was investigated by steady-state, time-resolved, and circular dichroism spectroscopy. The tryptophan (Trp) amino acid residues were used as an intrinsic fluorophore to decipher the structure-function relationship. As monitored by CD spectroscopy, the addition of TC causes the protein to alter some of its helical content although such changes are only marginal. The gradual decrease in fluorescence intensity of Trp can be ascribed to static quenching which takes place by the interaction of the drug with the protein. Besides Trp quenching, there is evidence of fluorescence resonance energy transfer (FRET) in all three proteins with different values of efficiency of energy transfer. Various quenching/binding and thermodynamic parameters associated with such drug-protein interactions have been estimated. The results thus obtained can provide guidelines to synthetic chemists to design and synthesize target-oriented drugs.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research, Bhopal ITI Campus (Gas Rahat) Building, Govindpura, Bhopal 462 023, Madhya Pradesh, India.
authors.forename: Uttam
authors.initials: U
authors.lastname: Anand
authors.forename: Chandrima
authors.initials: C
authors.lastname: Jash
authors.forename: Ravi Kiran
authors.initials: RK
authors.lastname: Boddepalli
authors.forename: Aseem
authors.initials: A
authors.lastname: Shrivastava
authors.forename: Saptarshi
authors.initials: S
authors.lastname: Mukherjee
mesh_terms: D000818:Animals; D002417:Cattle; D002645:Chickens; D002942:Circular Dichroism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D009113:Muramidase / Q000737:chemistry; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013752:Tetracycline / Q000737:chemistry*; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry
chemical_list: D011506:Proteins; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D014364:Tryptophan; D009113:Muramidase; D013752:Tetracycline