Involvement of tryptophan in the structural alterations of the rat ovarian LH/hCG receptor

Kolena, J; Scsuková, Soňa; Tatara, M; Vránová, J; Ježová, M

doi:10.1055/s-0029-1211769

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…60 The amphipathic character of tryptophan also explains its interfacial localization in membranes 61,62 which is characterized by unique motional and dielectric characteristics different from the bulk aqueous phase and the more isotropic hydrocarbon-like deeper regions of the membrane (see later). More importantly, apart from the structural and spectral properties, the role of tryptophan residues in maintaining the structure and function of both soluble [63][64][65] and membrane 60,[66][67][68][69][70][71][72] proteins has attracted considerable attention. The importance of tryptophan residues is exemplified by the fact that any perturbation to tryptophan residues (substitution, deletion, chemical modification, or photodamage) often results in reduction or loss of protein functionality.…”

Section: Intrinsic Fluorescence Of Proteins and Peptides: Tryptophan mentioning

confidence: 99%

Novel Insights Into Protein Structure and Dynamics Utilizing the Red Edge Excitation Shift Approach

Raghuraman

Kelkar

Chattopadhyay

Reviews in Fluorescence 2005

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A shift in the wavelength of maximum fluorescence emission toward higher wavelengths, caused by a corresponding shift in the excitation wavelength toward the red edge of the absorption band, is termed the red edge excitation shift (REES). This effect is mostly observed with polar fluorophores in motionally restricted media such as viscous solutions or condensed phases where the dipolar relaxation time for the solvent shell around a fluorophore is comparable to or longer than its fluorescence lifetime. REES arises from slow rates of solvent relaxation (reorientation) around an excited state fluorophore which depends on the motional restriction imposed on the solvent molecules in the immediate vicinity of the fluorophore. Utilizing this approach, it becomes possible to probe the mobility parameters of the environment itself (which is represented by the relaxing solvent molecules) using the fluorophore merely as a reporter group. Further, since the ubiquitous solvent for biological systems is water, the information obtained in such cases will come from the otherwise 'optically silent' water molecules. This makes REES extremely useful since hydration plays a crucial modulatory role in the formation and maintenance of organized molecular assemblies such as folded proteins in aqueous solutions and biological membranes. The application of REES as a powerful tool to monitor the organization and dynamics of a variety of soluble, cytoskeletal, and membrane-bound proteins is discussed.

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Section: Intrinsic Fluorescence Of Proteins and Peptides: Tryptophan mentioning

confidence: 99%

Novel Insights Into Protein Structure and Dynamics Utilizing the Red Edge Excitation Shift Approach

Raghuraman

Kelkar

Chattopadhyay

Reviews in Fluorescence 2005

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Tryptophan residue is essential for immunoreactivity of a diagnostically relevant peptide epitope of A. fumigatus

et al. 2005

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The role of tryptophan (Trp17) in immunoreactivity of P1, the diagnostically relevant peptide from a major allergen/antigen of Aspergillus fumigatus, was evaluated by chemically modifying tryptophanyl residue of P1. In BIAcore kinetic studies, unmodified P1 showed a 100-fold higher binding with ABPA (Allergic Bronchopulmonary Aspergillosis) patients' IgG [KD (equilibrium dissociation constant) = 2.74 e(-8) +/- 0.13 M] than the controls' IgG (KD = 2.97 e(-6) +/- 0.14 M), whereas chemically-modified P1 showed similar binding [KD patients' IgG = 3.25 e(-7) +/- 0.16 M, KD controls' IgG = 3.86 e(-7) +/- 0.19 M] indicating loss of specific immunoreactivity of P1 on tryptophan modification. Modified P1 showed loss of specific binding to IgE and IgG antibodies of ABPA patients in ELISA (Enzyme-Linked Immunosorbent Assay). The study infers that tryptophan residue (Trp17) is essential for immunoreactivity of P1.

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Structure-stabilizing effect of albumin on rat ovarian LH/hCG receptors

Kolena

Ježová

Vránová

et al. 1999

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The stabilizing effect of albumin on structure-functional alteration of LH/hCG receptors was analyzed by thermal perturbation technique. On exposing the membranes to bovine serum albumin (BSA) the heat inactivation profile of hCG-binding sites was shifted to a temperature higher by about 5 degreesC (T50 values). The receptor destabilizing action of arachidonic and oleic acids incorporated into ovarian membranes and reversal of this effect when BSA was used as fatty acid scavenger, may indicate that free fatty acids are responsible for the thermal instability of hCG-binding sites. This presumption was corroborated by digestion of membranes with phospholipase A2 (PLA2). This enzyme exerted effects on the thermal stability of the receptor protein resembling those observed upon insertion of fatty acids. The membrane fluidization induced by arachidonic acid can be reversed by BSA. However, alterations of lipid fluidity in membranes were not found to be a necessary prerequisite for stabilization of the LH/hCG receptor structure. Fluorescence quenching studies indicated that incorporation of oleic acid or digestion of membrane phospholipids with PLA2 elevated the accessibility of fluorophores for acrylamide. BSA scavenging of free fatty acids approached the quenching rate of control membranes. Analysis of fluorescence of membranes bound to monodansylcadaverine probe revealed that the negative surface charge derived from free fatty acids resulted in destabilization of the receptor protein. The effects of free fatty acids on membranes suggest that altered lipid-protein interactions may directly affect the stability of the LH/hCG receptor structure.

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Involvement of tryptophan in the structural alterations of the rat ovarian LH/hCG receptor

Cited by 3 publications

References 10 publications

Novel Insights Into Protein Structure and Dynamics Utilizing the Red Edge Excitation Shift Approach

Novel Insights Into Protein Structure and Dynamics Utilizing the Red Edge Excitation Shift Approach

Tryptophan residue is essential for immunoreactivity of a diagnostically relevant peptide epitope of A. fumigatus

Structure-stabilizing effect of albumin on rat ovarian LH/hCG receptors

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