T.I Syrejshchikova

Time-resolved spectroscopy of the probe fluorescence in the study of human blood protein dynamic structure on SR beam

Abstract Time-resolved spectroscopy on the SRS of the Daresbury Laboratory was used for the study of the human serum lipoproteins and human blood albumins with fluorescent probes K-37 and K-35, developed in Russia. The probe K-37 was found sensitive to the difference in dynamic properties of the lipid objects. Two sets of the parameters were used for the description of lipid dynamic structure: (1) time-resolved fluorescence spectra and (2) time-resolved fluorescence depolarization as a function of rotational mobility of lipid molecules. Each measured dynamic parameter reflected the monotonous changes of dynamic properties in the range: lipid spheres–very low density lipoproteins–low density lipoproteins–high density lipoproteins–phospholipid liposomes. The range is characterized by the increase of the ratio polar/ nonpolar lipids. Thus, time-resolved fluorescence could be used to detect some structural modifications in lipoproteins related to atherosclerosis and subsequent cardiovascular diseases development.

Station for the investigation of the decay kinetics of the fluorescence anisotropy of biological objects

Abstract A station for the investigation of the fluorescence intensity and anisotropy decay of biological objects is described. The station has been installed on the synchrotron radiation (SR) source S-60 of P.N. Lebedev Physical Institute and can be extended to investigations of the spatial structure of lipoproteins and biological membranes.

Characteristics of molecular fluorescence of a lipid probe in human blood lipoproteins exposed to synchrotron radiation

Abstract Measurements of the principal characteristics of lipid probe molecular fluorescence in four classes of human blood lipoproteins and in artifical membranes and lipoproteins were carried out. Two regimes of excitation were used: steady-state and pulsed (in SR beam). The lipid probe K-37 is used in medical practice for the determination of the amount of low density and very low density lipoproteins in human blood. The possibility to use the probe fluorescence in this way was found empirically. But biophysical properties of this phenomenon were not investigated up to now. This article is one of the stages of such investigations.

P03-210 Conformation of albumin binding sites are disturbed in schizophrenia

Aim Investigate some properties of albumin binding sites in schizophrenic patients. Methods Properties of serum albumin binding sites were studied using quenching of fluorescence of probe K-35 (N-carboxyphenylimide of dimethylaminonaphthalic acid) with nitrate anion. Serum samples were collected from 24 schizophrenic patients and 24 healthy volunteers. Results In the absence of quencher specific probe fluorescence in patients was 1,4 times higher than in controls. Fluorescent quenching constant for probe bound to albumin was 2,5 L/mol in patients versus 4,6 L/mol in volunteers (p Conclusions In schizophrenic patients conformational state of albumin binding sites is significantly disturbed that can lead to changes in protein-ligand interaction and to damage of main albumin functions (transport and detoxification) and aggravation of endotoxicosis.

The use of synchrotron radiation to investigate the localization of fluorescent probes in model lipoproteins

Abstract The radiationless energy transfer between fluorescent probes, including fluorescent derivatives of cholesterol incorporated into model lipoproteins, has been investigated in synchrotron radiation beams by means of stationary and dynamic measurements of fluoresence. This has allowed new information about probe localization to be obtained.

Serum albumin conformation in patients withmelancholic depression under antidepressant therapy

Discovery of biomarkers of mental disorders for evaluation of efficacy of psychopharmacotherapy is an important task. The last years it became clear that disturbances in molecular processes in pathological conditions can be connected with conformational changes in protein structure [1,2]. The aim of the study was to investigate the blood albumin conformation in patients with melancholic depression (MD) under pharmacotherapy using fluorescent laser spectroscopy.

A fluorescent reporter detects details of aromatic ligand interference in drug-binding sites of human serum albumin

Human serum albumin (HSA) transports many ligands including small aromatic molecules: metabolites, drugs etc. Phenylbutazone is an anti-inflammatory drug, which binds to the drug-binding site I of HSA. Its interaction with this site has been studied using a fluorescent dye, CAPIDAN, whose fluorescence in serum originates from HSA and is sensitive to the changes in HSA site I in some diseases. Its fluorescence in HSA solutions is strongly suppressed by phenylbutazone. This phenomenon seems to be a basic sign of a simple drug-dye competition. However, a more detailed study of the time-resolved fluorescence decay of CAPIDAN has shown that phenylbutazone lowers fluorescence without changing the total amount of bound dye. In brief, the HSA-bound dye forms three populations due to three types of environment at the binding sites. The first two populations probably have a rather strong Coulomb interaction with the positive charge of residues Arginine 218 or Arginine 222 in site I and are responsible for approximately 90% of the total fluorescence. Phenylbutazone blocks this interaction and therefore lowers this fluorescence. At the same time the binding of the third population increases considerably in the presence of phenylbutazone, and, as a result, the actual number of bound dye molecules remains almost unchanged despite the ligand competition. So, time resolved fluorescence of the reporter allows to observe details of interactions and interference of aromatic ligands in drug binding site I of HSA both in isolated HSA and in serum.