26 research outputs found
The change of cellular membranes on apoptosis: fluorescence detection
The strong plasma membrane asymmetry existing in living cells is lost on apoptosis, and it is commonly detected with the probes interacting strongly and specifically with phosphatidylserine (PS). This phospholipid becomes exposed to the cell surface, and the labeled annexin V is used for its detection. The requirement for early and Ca2+-independent detection of apoptosis in the formats of spectroscopy of cell suspensions, flow cytometry, microarray technology and confocal or two-photon microscopy stimulated efforts for the development of new methods. Since the PS exposure must produce integrated changes of electrostatic potential and hydration in the outer leaflet of cell membrane, its detection can be provided by direct response of smart fluorescence probes. This review is focused on basic mechanisms underlying the loss of membrane asymmetry during apoptosis and the principles lying in the background of new methods that demonstrate essential advantages over the annexin V-binding assay. The convenient wavelength-ratiometric technique based on fluorescent probe F2N12S is described in detail. It incorporates spontaneously into outer leaflet of cell membrane and the color change of its fluorescent emission associated with apoptosis can be easily detected. This article is part of a Special Issue entitled βApoptosis: Four Decades Laterβ
Modern views on the structure and dynamics of biological membranes
Essential changes have been recently observed in views on the functioning, structural and dynamic properties of biological membranes. The previous results on hierarchical cluster-type structure of membranes and role of protein and lipid components are reconsidered. An established fact of dramatic difference in lipid composition between external and internal monolayers of plasma membranes is important for understanding membrane phenomena. In particular, there exist the differences between monolayers in surface charge and potential, ion binding, interaction with protein molecules, etc. A glycolipid component of outer monolayer and interaction of inner monolayer with cytoskeleton allow the membrane by expanding the asymmetry to attain its important functional properties. All that requires more critical approach to numerous data obtained with simplified biomembrane analogs β lipid and protein-lipid bilayer structures. In the attempts to describe and model the properties of cellular membranes there is a timely necessity to shift from two-dimensionality (which reduces the analysis to membrane plane only) to more realistic three-dimensional models.ΠΡΡΠ°Π½Π½ΡΠΌ ΡΠ°ΡΠΎΠΌ Π²ΡΠ΄Π±ΡΠ»ΠΈΡΡ ΡΡΡΠΎΡΠ½Ρ Π·ΠΌΡΠ½ΠΈ Ρ ΠΏΠΎΠ³Π»ΡΠ΄Π°Ρ
Π½Π° ΡΡΠ½ΠΊΡΡΠΎΠ½ΡΠ²Π°Π½Π½Ρ Ρ ΡΡΡΡΠΊΡΡΡΠ½ΠΎ-Π΄ΠΈΠ½Π°ΠΌΡΡΠ½Ρ Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΡ Π±ΡΠΎΠ»ΠΎΠ³ΡΡΠ½ΠΈΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½. ΠΠ΅ΡΠ΅Π³Π»ΡΠ½ΡΡΠΎ Π΄Π°Π½Ρ ΡΠΎΠ΄ΠΎ ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΡ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΡ Π±ΡΠ΄ΠΎΠ²ΠΈ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½ Ρ ΡΠΎΠ»Ρ Π±ΡΠ»ΠΊΠΎΠ²ΠΈΡ
Ρ Π»ΡΠΏΡΠ΄Π½ΠΈΡ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΡΠ². ΠΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ ΡΠ°ΠΊΡ Π΄ΡΠ°ΠΌΠ°ΡΠΈΡΠ½ΠΎΡ ΡΡΠ·Π½ΠΈΡΡ Π»ΡΠΏΡΠ΄Π½ΠΎΠ³ΠΎ ΡΠΊΠ»Π°Π΄Ρ ΠΌΡΠΆ Π·ΠΎΠ²Π½ΡΡΠ½ΡΠΌ Ρ Π²Π½ΡΡΡΡΡΠ½ΡΠΌ ΠΌΠΎΠ½ΠΎΡΠ°ΡΠ°ΠΌΠΈ ΠΏΠ»Π°Π·ΠΌΠ°ΡΠΈΡΠ½ΠΈΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½, ΡΠΊΠΈΠΉ ΠΌΠ°Ρ Π²Π°ΠΆΠ»ΠΈΠ²Π΅ Π·Π½Π°ΡΠ΅Π½Π½Ρ Π΄Π»Ρ ΡΠΎΠ·ΡΠΌΡΠ½Π½Ρ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Π½ΠΈΡ
ΠΏΡΠΎΡΠ΅ΡΡΠ². ΠΠΎΠΊΡΠ΅ΠΌΠ°, ΡΡΠ½ΡΡΡΡ Π²ΡΠ΄ΠΌΡΠ½Π½ΠΎΡΡΡ ΠΌΡΠΆ ΠΌΠΎΠ½ΠΎΡΠ°ΡΠ°ΠΌΠΈ Ρ ΠΏΠΎΠ²Π΅ΡΡ
Π½Π΅Π²ΠΎΠΌΡ Π·Π°ΡΡΠ΄Ρ Ρ ΠΏΠΎΡΠ΅Π½ΡΡΠ°Π»Ρ, Π·Π²βΡΠ·ΡΠ²Π°Π½Π½Ρ ΡΠΎΠ½ΡΠ², Π²Π·Π°ΡΠΌΠΎΠ΄ΡΡ Π· ΠΌΠΎΠ»Π΅ΠΊΡΠ»Π°ΠΌΠΈ Π±ΡΠ»ΠΊΡΠ² ΡΠΎΡΠΎ. ΠΠ»ΡΠΊΠΎΠ»ΡΠΏΡΠ΄Π½ΠΈΠΉ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½Ρ Π·ΠΎΠ²Π½ΡΡΠ½ΡΠΎΠ³ΠΎ ΠΌΠΎΠ½ΠΎΡΠ°ΡΡ Ρ Π²Π·Π°ΡΠΌΠΎΠ΄ΡΡ Π· ΡΠΈΡΠΎΡΠΊΠ΅Π»Π΅ΡΠΎΠΌ Π²Π½ΡΡΡΡΡΠ½ΡΠΎΠ³ΠΎ ΠΌΠΎΠ½ΠΎΡΠ°ΡΡ Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡΡΡ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Ρ ΡΠ΅ΡΠ΅Π· ΠΏΠΎΠ³Π»ΠΈΠ±Π»Π΅Π½Π½Ρ Π°ΡΠΈΠΌΠ΅ΡΡΡΡ Π½Π°Π±ΡΡΠΈ Π²Π°ΠΆΠ»ΠΈΠ²ΠΈΡ
ΡΡΠ½ΠΊΡΡΠΎΠ½Π°Π»ΡΠ½ΠΈΡ
Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΠ΅ΠΉ. ΠΠ΅ΠΎΠ±Ρ
ΡΠ΄Π½ΠΈΠΉ Π±ΡΠ»ΡΡ ΠΊΡΠΈΡΠΈΡΠ½ΠΈΠΉ ΠΏΡΠ΄Ρ
ΡΠ΄ Π΄ΠΎ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡΠ², ΠΎΠ΄Π΅ΡΠΆΠ°Π½ΠΈΡ
Π·Ρ ΡΠΏΡΠΎΡΠ΅Π½ΠΈΠΌΠΈ Π°Π½Π°Π»ΠΎΠ³Π°ΠΌΠΈ Π±ΡΠΎΠΌΠ΅ΠΌΠ±ΡΠ°Π½ β Π»ΡΠΏΡΠ΄Π½ΠΈΠΌΠΈ Ρ Π±ΡΠ»ΠΊΠΎΠ²ΠΎ-Π»ΡΠΏΡΠ΄Π½ΠΈΠΌΠΈ Π±ΡΡΠ°ΡΠΎΠ²ΠΈΠΌΠΈ ΡΡΡΡΠΊΡΡΡΠ°ΠΌΠΈ. Π£ ΡΠΏΡΠΎΠ±Π°Ρ
ΠΎΠΏΠΈΡΠ°Π½Π½Ρ Ρ ΠΌΠΎΠ΄Π΅Π»ΡΠ²Π°Π½Π½Ρ Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΠ΅ΠΉ ΠΊΠ»ΡΡΠΈΠ½Π½ΠΈΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½ ΡΡΠ½ΡΡ ΠΏΠΎΡΡΠ΅Π±Π° Π²ΡΠ΄Ρ
ΠΎΠ΄Ρ Π²ΡΠ΄ Π΄Π²ΠΎΠ²ΠΈΠΌΡΡΠ½ΠΎΡΡΡ (ΡΠΎ Π·Π²ΠΎΠ΄ΠΈΡΡ Π°Π½Π°Π»ΡΠ· Π»ΠΈΡΠ΅ Π² ΠΏΠ»ΠΎΡΠΈΠ½Ρ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½ΠΈ) Ρ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Ρ Π΄ΠΎ Π±ΡΠ»ΡΡ ΡΠ΅Π°Π»ΡΡΡΠΈΡΠ½ΠΈΡ
ΡΡΠΈΠ²ΠΈΠΌΡΡΠ½ΠΈΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ.Π ΠΏΠΎΡΠ»Π΅Π΄Π½Π΅Π΅ Π²ΡΠ΅ΠΌΡ ΠΏΡΠΎΠΈΠ·ΠΎΡΠ»ΠΈ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ Π²ΠΎ Π²Π·Π³Π»ΡΠ΄Π°Ρ
Π½Π° ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΈ ΡΡΡΡΠΊΡΡΡΠ½ΠΎ-Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° Π±ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½. ΠΠ΅ΡΠ΅ΡΠΌΠΎΡΡΠ΅Π½Ρ Π΄Π°Π½Π½ΡΠ΅ ΠΎ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ½ΠΎΠΌ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠΌ ΡΡΡΠΎΠ΅Π½ΠΈΠΈ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½ ΠΈ ΡΠΎΠ»ΠΈ Π±Π΅Π»ΠΊΠΎΠ²ΡΡ
ΠΈ Π»ΠΈΠΏΠΈΠ΄Π½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠΎΠ². Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ ΡΠ°ΠΊΡ Π΄ΡΠ°ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ°Π·Π»ΠΈΡΠΈΠΉ Π»ΠΈΠΏΠΈΠ΄Π½ΠΎΠ³ΠΎ ΡΠΎΡΡΠ°Π²Π° ΠΌΠ΅ΠΆΠ΄Ρ Π½Π°ΡΡΠΆΠ½ΡΠΌ ΠΈ Π²Π½ΡΡΡΠ΅Π½Π½ΠΈΠΌ ΠΌΠΎΠ½ΠΎΡΠ»ΠΎΡΠΌΠΈ ΠΏΠ»Π°Π·ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½, ΠΈΠΌΠ΅ΡΡΠΈΠΉ Π±ΠΎΠ»ΡΡΠΎΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΠ΅ Π΄Π»Ρ ΠΏΠΎΠ½ΠΈΠΌΠ°Π½ΠΈΡ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Π½ΡΡ
ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ². Π ΡΠ°ΡΡΠ½ΠΎΡΡΠΈ, ΡΡΡΠ΅ΡΡΠ²ΡΡΡ ΡΠ°Π·Π»ΠΈΡΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ ΠΌΠΎΠ½ΠΎΡΠ»ΠΎΡΠΌΠΈ Π² ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠ½ΠΎΠΌ Π·Π°ΡΡΠ΄Π΅ ΠΈ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»Π΅, ΡΠ²ΡΠ·ΡΠ²Π°Π½ΠΈΠΈ ΠΈΠΎΠ½ΠΎΠ², Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠΈ Ρ Π±Π΅Π»ΠΊΠΎΠ²ΡΠΌΠΈ ΠΌΠΎΠ»Π΅ΠΊΡΠ»Π°ΠΌΠΈ ΠΈ Ρ. Π΄. ΠΠ»ΠΈΠΊΠΎΠ»ΠΈΠΏΠΈΠ΄Π½ΡΠΉ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½Ρ Π²Π½Π΅ΡΠ½Π΅Π³ΠΎ ΠΌΠΎΠ½ΠΎΡΠ»ΠΎΡ ΠΈ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ Ρ ΡΠΈΡΠΎΡΠΊΠ΅Π»Π΅ΡΠΎΠΌ Π²ΠΎ Π²Π½ΡΡΡΠ΅Π½Π½Π΅ΠΌ ΠΌΠΎΠ½ΠΎΡΠ»ΠΎΠ΅ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Π΅ Π·Π° ΡΡΠ΅Ρ ΡΠ³Π»ΡΠ±Π»Π΅Π½ΠΈΡ Π°ΡΠΈΠΌΠΌΠ΅ΡΡΠΈΠΈ ΠΏΡΠΈΠΎΠ±ΡΠ΅ΡΡΠΈ Π²Π°ΠΆΠ½ΡΠ΅ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π°. ΠΠ΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌ Π±ΠΎΠ»Π΅Π΅ ΠΊΡΠΈΡΠΈΡΠ½ΡΠΉ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ ΠΊ ΠΌΠ½ΠΎΠ³ΠΎΡΠΈΡΠ»Π΅Π½Π½ΡΠΌ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ°ΠΌ, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΠΌ Ρ ΡΠΏΡΠΎΡΠ΅Π½Π½ΡΠΌΠΈ Π°Π½Π°Π»ΠΎΠ³Π°ΠΌΠΈ Π±ΠΈΠΎΠΌΠ΅ΠΌΠ±ΡΠ°Π½ β Π»ΠΈΠΏΠΈΠ΄Π½ΡΠΌΠΈ ΠΈ Π±Π΅Π»ΠΊΠΎΠ²ΠΎ-Π»ΠΈΠΏΠΈΠ΄Π½ΡΠΌΠΈ Π±ΠΈΡΠ»ΠΎΠΉΠ½ΡΠΌΠΈ ΡΡΡΡΠΊΡΡΡΠ°ΠΌΠΈ. Π ΠΏΠΎΠΏΡΡΠΊΠ°Ρ
ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ ΠΈ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ²ΠΎΠΉΡΡΠ² ΠΊΠ»Π΅ΡΠΎΡΠ½ΡΡ
ΠΌΠ΅ΠΌΠ±ΡΠ°Π½ ΡΡΡΠ΅ΡΡΠ²ΡΠ΅Ρ Π°ΠΊΡΡΠ°Π»ΡΠ½Π°Ρ ΠΏΠΎΡΡΠ΅Π±Π½ΠΎΡΡΡ ΠΎΡΡ
ΠΎΠ΄Π° ΠΎΡ Π΄Π²ΡΡ
ΠΌΠ΅ΡΠ½ΠΎΡΡΠΈ (ΡΡΠΎ ΡΠ²ΠΎΠ΄ΠΈΡ Π°Π½Π°Π»ΠΈΠ· Π»ΠΈΡΡ Π² ΠΏΠ»ΠΎΡΠΊΠΎΡΡΡ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Ρ) ΠΈ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Π° ΠΊ Π±ΠΎΠ»Π΅Π΅ ΡΠ΅Π°Π»ΠΈΡΡΠΈΡΠ½ΡΠΌ ΡΡΠ΅Ρ
ΠΌΠ΅ΡΠ½ΡΠΌ ΠΌΠΎΠ΄Π΅Π»ΡΠΌ
Spectroscopic Studies of New Fluorescent Nanomaterial Composed of Silver Atoms and Organic Dye
The novel fluorescent nanostructures are synthesized in a simple one-step process by UV light illumination of silver salt in a mixture with organic dye Thioflavin T. The latter serves both as a sensitizer in photoreaction and as molecular support. The most stable composite structures are obtained in 2-propanol. They are characterized by absorption spectra that are quite different from that of the dye and by strong excitation and emission bands with the maxima at 340 nm and 450 nm correspondingly. We suggest that this photoreaction product consists of two silver atoms and two dye molecules. We believe that this new fluorescent nanoscale material will find many applications in biosensing and bioimaging technologies.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3526
Fluorescent Few-Atom Clusters of Silver Formed in Organic Solvents on Polymeric Supports
Few-atom silver clusters are fluorophores with a set of attractive properties including sub-nanometer
size, high quantum yield and large Stokes shift. Sharing high photostability with semiconductor quantum
dots but being of much smaller size, lacking blinking and with expected lack of toxicity, they are especially
attractive for biological imaging, down to single molecules. No less promising are their applications in
chemical sensing and biosensing as well as for molecular optic and electronic devices on a single molecular
level. We demonstrate that it is not a unique property of water that can provide the formation and stability
of silver clusters. They can be produced on photoreduction in different organic solvents using the same polymeric
template. Unique photophysical properties of these clusters share both similarities and differences
to that of organic dyes.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3512
Clustering Monte Carlo simulations of the hierarchical protein folding on a simple lattice model
A role of specific collective motions and clustering behavior in protein folding was investigated using simple 2D lattice models. Two model peptides, which have the sequences of hierarchical and non-hierarchical design, were studied comparatively. Simulations were performed using three methods: Metropolis Monte Carlo with the local move set, Metropolis Monte Carlo with unspecific rigid rotations, and the Clustering Monte Carlo (CMC) algorithm that has been recently described by the authors. The latter was developed with particular aim to provide a realistic description of cluster dynamics. We present convincing evidence that the folding pathways and kinetics of hierarchically folding sequence are not adequately described in conventional MC simulations. In this case the account for cluster dynamics provided by CMC algorithm reveals important features of folding of hierarchically organized sequences. Our data suggest that the methods, which enable specific cluster motions, should be used for realistic description of hierarchical folding.ΠΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½ΠΎ ΡΠΎΠ»Ρ ΡΠΏΠ΅ΡΠΈΡΡΡΠ½ΠΈΡ
ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½ΠΈΡ
ΡΡΡ
ΡΠ² ΡΠ° ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΡ ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΠΈ Ρ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ Π±ΡΠ»ΠΊΡΠ² Π· Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½ΡΠΌ ΠΏΡΠΎΡΡΠΈΡ
Π΄Π²ΠΎΒΠ²ΠΈΠΌΡΡΠ½ΠΈΡ
Π³ΡΠ°ΡΠΊΠΎΠ²ΠΈΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ. ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΠΏΠΎΡΡΠ²Π½ΡΠ»ΡΠ½ΠΈΠΉ Π°Π½Π°Π»ΡΠ· ΠΏΠ΅ΠΏΡΠΈΠ΄ΡΠ² Π· ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΡ ΡΠ° Π½Π΅ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΡ Π±ΡΠ΄ΠΎΠ²ΠΎΡ. ΠΠΎΠ΄Π΅Π»ΡΠ²Π°Π½ΒΠ½Ρ Π·Π΄ΡΠΉΡΠ½ΡΠ²Π°Π»ΠΈ Π·Π° Π΄ΠΎΠΏΠΎΠΌΠΎΠ³ΠΎΡ ΡΡΡΠΎΡ
ΠΌΠ΅ΡΠΎΠ΄ΡΠ²: ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ Π· Π»ΠΎΠΊΠ°Π»ΡΠ½ΠΈΠΌ Π½Π°Π±ΠΎΡΠΎΠΌ ΡΡΡ
ΡΠ², ΡΡΠ°Π½Π΄Π°ΡΡΒΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ Π· Π½Π΅ΡΠΏΠ΅ΡΠΈΡΡΡΠ½ΠΈΠΌΠΈ ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½ΠΈΠΌΠΈ ΠΎΠ±Π΅ΡΡΠ°Π½Π½ΡΠΌΠΈ ΡΠ° ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ (CMC) Π·Π°ΠΏΡΠΎΠΏΠΎΠ½ΠΎΠ²Π°Π½ΠΎΠ³ΠΎ Π°Π²ΡΠΎΡΠ°ΠΌΠΈ Π΄Π»Ρ ΡΠ΅Π°Π»ΡΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΡΠ²Π°Π½Π½Ρ Π΄ΠΈΠ½Π°ΠΌΡΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΒΡΡΠ². ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΠΎ ΡΠ»ΡΡ
ΠΈ ΡΠ° ΠΊΡΠ½Π΅ΡΠΈΠΊΠ° ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ Π½Π΅ ΠΌΠΎΠΆΡΡΡ Π±ΡΡΠΈ Π°Π΄Π΅ΠΊΠ²Π°ΡΠ½ΠΎ ΠΎΠΏΠΈΡΠ°Π½Ρ Π·Π²ΠΈΡΠ°ΠΉΠ½ΠΈΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ. Π£ ΡΡΠΎΠΌΡ Π²ΠΈΠΏΠ°Π΄ΠΊΡ Π²ΡΠ°Ρ
ΡΠ²Π°Π½Π½Ρ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΡ Π΄ΠΈΠ½Π°ΠΌΡΠΊΠΈ Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ CMC Π²ΠΈΡΠ²Π»ΡΡ Π²Π°ΠΆΠ»ΠΈΠ²Ρ ΡΠΈΡΠΈ ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ. ΠΠΈΠ·Π½Π°ΡΠ΅Π½ΠΎ, up Π΄Π»Ρ ΡΠ΅Π°Π»ΡΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΡΠ²Π°Π½Π½Ρ ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ ΠΏΠΎΡΡΡΠ±Π½ΠΎ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΠ²Π°ΡΠΈ ΡΠΎΠ·ΡΠ°Ρ
ΡΠ½ΠΊΠΎΠ²Ρ ΠΌΠ΅ΡΠΎΠ΄ΠΈ, ΡΠΊΡ Π²ΡΠ°Ρ
ΠΎΠ²ΡΡΡΡ ΡΠΏΠ΅ΒΡΠΈΡΡΡΠ½Ρ ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½Ρ ΡΡΡ
ΠΈ.ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π° ΡΠΎΠ»Ρ ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠ»Π»Π΅ΠΊΡΠΈΠ²Π½ΡΡ
Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΠΉ ΠΈ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ² Π² ΡΠΎΠ»Π΄ΠΈΠ½Π³Π΅ Π±Π΅Π»ΠΊΠΎΠ² Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΠΏΡΠΎΒΡΡΡΡ
Π΄Π²ΡΡ
ΠΌΠ΅ΡΠ½ΡΡ
ΡΠ΅ΡΠ΅ΡΠΎΡΠ½ΡΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ. ΠΡΠΎΠ²Π΅Π΄Π΅Π½ ΡΡΠ°Π²Π½ΠΈΡΠ΅Π»ΡΒ Π½ΡΠΉ Π°Π½Π°Π»ΠΈΠ· ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° ΠΏΠ΅ΠΏΡΠΈΠ΄ΠΎΠ² Ρ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈ Π½Π΅ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΒΡΠΊΠΎΠΉ ΡΡΡΡΠΊΡΡΡΠΎΠΉ. ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΠ»ΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΡΠ΅Ρ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ²: ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ Ρ Π»ΠΎΠΊΠ°Π»ΡΒΠ½ΠΈΠΌ Π½Π°Π±ΠΎΡΠΎΠΌ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΠΉ, ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° Ρ Π½Π΅ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΒΡΠΊΠΈΠΌΠΈ ΠΊΠΎΠ»Π»Π΅ΠΊΡΠΈΠ²Π½ΡΠΌΠΈ Π²ΡΠ°ΡΠ΅Π½ΠΈΡΠΌΠΈ ΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ (CMC), ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π½ΠΎΠ³ΠΎ Π°Π²ΡΠΎΡΠ°ΠΌΠΈ Π΄Π»Ρ ΡΠ΅Π°Π»ΠΈΒΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ². ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΡΠΈ ΠΈ ΠΊΠΈΠ½Π΅ΡΠΈΠΊΠ° ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° Π½Π΅ ΠΌΠΎΠ³ΡΡ Π±ΡΡΡ Π°Π΄Π΅ΠΊΠ²Π°ΡΒΠ½ΠΎ ΠΎΠΏΠΈΡΠ°Π½Ρ ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ. Π ΡΡΠΎΠΌ ΡΠ»ΡΡΠ°Π΅ ΡΡΠ΅Ρ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠΉ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ Π² ΠΌΠ΅ΡΠΎΠ΄Π΅ CMC Π²ΡΡΠ²Π»ΡΠ΅Ρ Π²Π°ΠΆΠ½ΡΠ΅ ΠΎΡΠΎΒΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π°. ΠΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΎ, ΡΡΠΎ Π΄Π»Ρ ΡΠ΅Π°Π»ΠΈΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° Π΄ΠΎΠ»ΠΆΠ½Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡΡΡ ΠΌΠ΅ΡΠΎΠ΄Ρ, ΡΡΠΈΡΡΠ²Π°ΡΡΠΈΠ΅ ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΊΠΎΠ»Π»Π΅ΠΊΒΡΠΈΠ²Π½ΡΠ΅ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ
Clustering Monte Carlo simulations of the hierarchical protein folding on a simple lattice model
A role of specific collective motions and clustering behavior in protein folding was investigated using simple 2D lattice models. Two model peptides, which have the sequences of hierarchical and non-hierarchical design, were studied comparatively. Simulations were performed using three methods: Metropolis Monte Carlo with the local move set, Metropolis Monte Carlo with unspecific rigid rotations, and the Clustering Monte Carlo (CMC) algorithm that has been recently described by the authors. The latter was developed with particular aim to provide a realistic description of cluster dynamics. We present convincing evidence that the folding pathways and kinetics of hierarchically folding sequence are not adequately described in conventional MC simulations. In this case the account for cluster dynamics provided by CMC algorithm reveals important features of folding of hierarchically organized sequences. Our data suggest that the methods, which enable specific cluster motions, should be used for realistic description of hierarchical folding.ΠΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½ΠΎ ΡΠΎΠ»Ρ ΡΠΏΠ΅ΡΠΈΡΡΡΠ½ΠΈΡ
ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½ΠΈΡ
ΡΡΡ
ΡΠ² ΡΠ° ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΡ ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΠΈ Ρ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ Π±ΡΠ»ΠΊΡΠ² Π· Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½ΡΠΌ ΠΏΡΠΎΡΡΠΈΡ
Π΄Π²ΠΎΒΠ²ΠΈΠΌΡΡΠ½ΠΈΡ
Π³ΡΠ°ΡΠΊΠΎΠ²ΠΈΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ. ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΠΏΠΎΡΡΠ²Π½ΡΠ»ΡΠ½ΠΈΠΉ Π°Π½Π°Π»ΡΠ· ΠΏΠ΅ΠΏΡΠΈΠ΄ΡΠ² Π· ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΡ ΡΠ° Π½Π΅ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΡ Π±ΡΠ΄ΠΎΠ²ΠΎΡ. ΠΠΎΠ΄Π΅Π»ΡΠ²Π°Π½ΒΠ½Ρ Π·Π΄ΡΠΉΡΠ½ΡΠ²Π°Π»ΠΈ Π·Π° Π΄ΠΎΠΏΠΎΠΌΠΎΠ³ΠΎΡ ΡΡΡΠΎΡ
ΠΌΠ΅ΡΠΎΠ΄ΡΠ²: ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ Π· Π»ΠΎΠΊΠ°Π»ΡΠ½ΠΈΠΌ Π½Π°Π±ΠΎΡΠΎΠΌ ΡΡΡ
ΡΠ², ΡΡΠ°Π½Π΄Π°ΡΡΒΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ Π· Π½Π΅ΡΠΏΠ΅ΡΠΈΡΡΡΠ½ΠΈΠΌΠΈ ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½ΠΈΠΌΠΈ ΠΎΠ±Π΅ΡΡΠ°Π½Π½ΡΠΌΠΈ ΡΠ° ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ (CMC) Π·Π°ΠΏΡΠΎΠΏΠΎΠ½ΠΎΠ²Π°Π½ΠΎΠ³ΠΎ Π°Π²ΡΠΎΡΠ°ΠΌΠΈ Π΄Π»Ρ ΡΠ΅Π°Π»ΡΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΡΠ²Π°Π½Π½Ρ Π΄ΠΈΠ½Π°ΠΌΡΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΒΡΡΠ². ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΠΎ ΡΠ»ΡΡ
ΠΈ ΡΠ° ΠΊΡΠ½Π΅ΡΠΈΠΊΠ° ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ Π½Π΅ ΠΌΠΎΠΆΡΡΡ Π±ΡΡΠΈ Π°Π΄Π΅ΠΊΠ²Π°ΡΠ½ΠΎ ΠΎΠΏΠΈΡΠ°Π½Ρ Π·Π²ΠΈΡΠ°ΠΉΠ½ΠΈΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ. Π£ ΡΡΠΎΠΌΡ Π²ΠΈΠΏΠ°Π΄ΠΊΡ Π²ΡΠ°Ρ
ΡΠ²Π°Π½Π½Ρ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΡ Π΄ΠΈΠ½Π°ΠΌΡΠΊΠΈ Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ CMC Π²ΠΈΡΠ²Π»ΡΡ Π²Π°ΠΆΠ»ΠΈΠ²Ρ ΡΠΈΡΠΈ ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ. ΠΠΈΠ·Π½Π°ΡΠ΅Π½ΠΎ, up Π΄Π»Ρ ΡΠ΅Π°Π»ΡΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΡΠ²Π°Π½Π½Ρ ΡΡΡΠ°ΡΡ
ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Ρ ΠΏΠΎΡΡΡΠ±Π½ΠΎ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΠ²Π°ΡΠΈ ΡΠΎΠ·ΡΠ°Ρ
ΡΠ½ΠΊΠΎΠ²Ρ ΠΌΠ΅ΡΠΎΠ΄ΠΈ, ΡΠΊΡ Π²ΡΠ°Ρ
ΠΎΠ²ΡΡΡΡ ΡΠΏΠ΅ΒΡΠΈΡΡΡΠ½Ρ ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π½Ρ ΡΡΡ
ΠΈ.ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π° ΡΠΎΠ»Ρ ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠ»Π»Π΅ΠΊΡΠΈΠ²Π½ΡΡ
Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΠΉ ΠΈ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ² Π² ΡΠΎΠ»Π΄ΠΈΠ½Π³Π΅ Π±Π΅Π»ΠΊΠΎΠ² Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΠΏΡΠΎΒΡΡΡΡ
Π΄Π²ΡΡ
ΠΌΠ΅ΡΠ½ΡΡ
ΡΠ΅ΡΠ΅ΡΠΎΡΠ½ΡΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ. ΠΡΠΎΠ²Π΅Π΄Π΅Π½ ΡΡΠ°Π²Π½ΠΈΡΠ΅Π»ΡΒ Π½ΡΠΉ Π°Π½Π°Π»ΠΈΠ· ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° ΠΏΠ΅ΠΏΡΠΈΠ΄ΠΎΠ² Ρ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈ Π½Π΅ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΒΡΠΊΠΎΠΉ ΡΡΡΡΠΊΡΡΡΠΎΠΉ. ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΠ»ΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΡΠ΅Ρ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ²: ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ Ρ Π»ΠΎΠΊΠ°Π»ΡΒΠ½ΠΈΠΌ Π½Π°Π±ΠΎΡΠΎΠΌ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΠΉ, ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° Ρ Π½Π΅ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΒΡΠΊΠΈΠΌΠΈ ΠΊΠΎΠ»Π»Π΅ΠΊΡΠΈΠ²Π½ΡΠΌΠΈ Π²ΡΠ°ΡΠ΅Π½ΠΈΡΠΌΠΈ ΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΠΎΠ½ΡΠ΅-ΠΠ°ΡΠ»ΠΎ (CMC), ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π½ΠΎΠ³ΠΎ Π°Π²ΡΠΎΡΠ°ΠΌΠΈ Π΄Π»Ρ ΡΠ΅Π°Π»ΠΈΒΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ². ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΡΠΈ ΠΈ ΠΊΠΈΠ½Π΅ΡΠΈΠΊΠ° ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° Π½Π΅ ΠΌΠΎΠ³ΡΡ Π±ΡΡΡ Π°Π΄Π΅ΠΊΠ²Π°ΡΒΠ½ΠΎ ΠΎΠΏΠΈΡΠ°Π½Ρ ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ. Π ΡΡΠΎΠΌ ΡΠ»ΡΡΠ°Π΅ ΡΡΠ΅Ρ ΠΊΠ»Π°ΡΡΠ΅ΡΠ½ΠΎΠΉ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ Π² ΠΌΠ΅ΡΠΎΠ΄Π΅ CMC Π²ΡΡΠ²Π»ΡΠ΅Ρ Π²Π°ΠΆΠ½ΡΠ΅ ΠΎΡΠΎΒΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π°. ΠΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΎ, ΡΡΠΎ Π΄Π»Ρ ΡΠ΅Π°Π»ΠΈΡΡΠΈΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ΅ΡΠ°ΡΡ
ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ»Π΄ΠΈΠ½Π³Π° Π΄ΠΎΠ»ΠΆΠ½Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡΡΡ ΠΌΠ΅ΡΠΎΠ΄Ρ, ΡΡΠΈΡΡΠ²Π°ΡΡΠΈΠ΅ ΡΠΏΠ΅ΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΊΠΎΠ»Π»Π΅ΠΊΒΡΠΈΠ²Π½ΡΠ΅ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ
Fluorescence spectroscopy in polymer science
Polymer science is an interdisciplinary field, combining chemistry, physics, and in some cases biology. Structure, morphology, and dynamical phenomena in natural and synthetic polymers can be addressed using fluorescence spectroscopy. The most attractive aspect of fluorescent reporters is that their fluorescence parameters can give information on the nanometer length scale with an exceptional sensitivity, which allows data acquisition with submicrometer spatial resolution and millisecond time resolution. The use of fluorescent reporter molecules is, in principle, an invasive technique. Because of the large size of polymer molecules, however, small fluorescent reporter molecules of a length scale of <β2 nm can be considered a small perturbation. Because of the enormous importance of synthetic polymers in our technology-based societies, almost every conceivable experimental technique has been applied in this field, but most of these tend to address the sample on a macroscopic scale. This chapter gives illustrative examples of the power of molecular fluorescence for investigating several microscopic aspects of polymer science
Excited state and ground state proton transfer rates of 3-hydroxyflavone and its derivatives studied by shpol'skii spectroscopy: The influence of redistribution of electron density
We studied the mechanisms of excited-state intramolecular proton transfer (ESIPT) and ground-state back proton transfer (BPT) in 3-hydroxyflavone (3HF) at cryogenic temperatures. The focus was on substituents that change the distribution of electronic density on the chromophore and their influence on these reaction rates. Shpol'skii spectroscopy was applied for comparative studies of three compounds: 3HF, 3-hydroxy-4β²-methoxyflavone (3HF-4β²OMe), and 2-furyl-3-hydroxychromone (3HC-F). By comparing the spectral bandwidths with those of deuterated analogues, we could distinguish the lifetime broadening components in the high-resolution excitation and emission spectra, from which the time constants of the ESIPT and BPT reactions were calculated. The time constants for the ESIPT reaction were 0.093 ps for 3HF, 0.21 ps for 3HF-4β²OMe, and slower than 0.6 ps for 3HC-F. For the same compounds, the BPT rates were 0.21, 0.47, and >2 ps, respectively. No change in bandwidth was observed over the temperature range 4-20 K, in agreement with a tunneling mechanism. Estimates for the barrier heights and proton-transfer distances are given. In addition, a systematic change in O-H bond strengths between ground and excited states was calculated from the isotope effect, observed as the shifts of the 0-0 bands in the excitation and emission spectra upon deuteration, The substantial effect of electron donating substituents on the rates of ESIPT and BPT reactions is in agreement with these changes
Solvent influence on excited-state intramolecular proton transfer in 3-hydroxychromone derivatives studied by cryogenic high-resolution fluorescence spectroscopy
High-resolution Shpol'skii spectra (recorded at 10 K in n-octane) of 3-hydroxychromone (3HC) substituted at the 2-position with a furan (3HC-F), a benzofuran (3HC-BF) or a naphthofuran group (3HC-NF) are presented. Being close analogues of 3-hydroxyflavone (3HF), these compounds can undergo excited-state intramolecular proton transfer (ESIPT). Luminescence can occur from the normal N* state (blue) or from the tautomeric T* state (green). Whether blue or green emission is observed is strongly dependent on hydrogen-bonding interactions with the environment. For all three chromones studied, high-resolution emission spectra in the green region (T*βT) were obtained in pure n-octane, showing four sites with distinct emission bands and detailed vibrational structures, whereas no blue emission was detected. Contrary to the spectra published for 3HF, the emission lines were very narrow (line-broadening effects beyond detection) which implies that the ESIPT rate constants are >1