PubMed Health⌕ Search

Biomedical subjects

V F Morozov

Publications and source records attributed to V F Morozov.

8 recordsLinked to original sources
PubMed2005

The helix-coil transition in heterogeneous double stranded DNA: microcanonical method.

A microscopic Potts-like one-dimensional model with many-particle interactions is developed to construct a statistical mechanical description of the melting of heterogeneous sequence duplex DNA. For this model, referred as the generalized model of polypeptide chains (GMPC), a closed-form expression for the free energy is derived. The characteristic equation of the model enables estimates on the melting temperature and transition interval, consistent with results obtained from more classical approaches. From the characteristic equation of the model, the temperature-dependent statistical weight parameter for helical states is evaluated. This parameter is shown to change throughout the transition from a harmonic form in early regions of the transition to an arithmetic form in later stages. The GMPC is extended to consider the influence of sequence heterogeneity in the melting of duplex DNA.

Algorithms↗
PubMed1995

The helix-coil transition in polypeptides: a microscopic approach. II.

In the framework of an earlier constructed model [N.S. Ananikyan et al. (1990) Biopolymers, Vol. 30, pp. 357-367], some analytical estimates for the correlation length and degree of helicity near the transition point were obtained in the case of an arbitrary topology of hydrogen bond closing (delta). It was shown that the Zimm-Bragg cooperativity parameter sigma is determined by the set of (delta-1) amino acid residues and so is nonlocal. An analytic expression for cooperativity parameters in a heteropolypeptide chain was obtained and numerical calculations showed that in case of heteropolypeptide with random primary structure the nonlocality of cooperativity parameter influenced the temperature dependence of helicity degree.

Hydrogen Bonding↗
PubMedDate not supplied

[Helix-coil transitions of a polypeptide in a two-component solvent].

A microscopic model is considered of a helix-coil transition of polypeptides in a two-component solvent one of whose components competes for the formation of hydrogen bonds with the peptide group. It is shown that by a redetermination of the temperature parameter the model is reduced to a polypeptide chain without the solvent. Behavior of the transition parameters is calculated in relation to the solvent concentration competing for the formation of hydrogen bonds at different parameters of polypeptide-solvent interaction.

Mathematics↗
PubMedDate not supplied

[Calculation of parameters of the phenomenological theory of helix-coil transition in polypeptides based on a microscopic model].

An expression for the partition function of the model including only two parameters-U (energy of hydrogen bond) and Q (the number of conformations of the repeating unit) with Hamiltonian is obtained. This expression has the form of algebraic series with the number of members approximately N3, N being the length of the chain. The results of calculations of the temperature relationship of helicity degree are presented for different values of N. The transition width and the parameter of cooperativity are calculated.

Mathematics↗
PubMedDate not supplied

[The epidemiological characteristics of HIV infection in Ukraine].

The paper presents results of screening tests involving different groups of the population in the Ukraine, for antibodies to HIV, findings from epidemiologic investigation into cases with HIV-infection, with a view to outlining epidemiologic situation and assessing effectiveness of antiepidemic measures. HIV-transmission through sexual contacts is the commonest way of HIV-transportation in the Ukraine (66.1% of all cases of infection). An attempt is made of giving a short-term prognosis of epidemic situation in the Ukraine over a period of up to 1995. A conclusion is reached on the necessity of strengthening preventive measures with the view of influencing the unsafe forms of sexual behaviour.

Adult↗
PubMedDate not supplied

[Modification of the DNA spatial structure when complexed with cisplatin].

The experimental and theoretical analyses of the conformational transitions of DNA-cis-platinum complexes have been carried out. It is shown that at low concentrations of the ligand, the thermodynamic parameters of the helix-coil transition of the complexes are not the result of the local B-->A transition.

Animals↗