Helix Coil Transition
Mostrando 1-12 de 77 artigos, teses e dissertações.
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1. Denaturation processes of collagen from cow bones as a function of temperature
ABSTRACT The thermal stability of collagen is of great interest for the scientific communities both of medicine and archaeology. In medicine, the interest is focused to the reconstruction and repair of bone and cartilage, given the frequency and importance of pathological situations. In contrast, in archaeology the interest is focused to infer from buried an
Matéria (Rio J.). Publicado em: 19/07/2018
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2. MOLECULAR CHARACTERIZATION OF BIOPOLIMERS IN SOLUTION BY COMPUTATIONAL SIMULATION / Caracterização molecular de biopolímeros em solução utilizando simulação computacional
Computer simulation methods were used to characterize the structure and molecular properties of natural and synthetic biopolymers in aqueous solution. The polysaccharides chitin and chitosan, and aliphatic polypeptides were studied. The interest on the chitin and chitosan biopolymers is because of their biodegradability, biocompatibility and potential use as
Publicado em: 2009
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3. Dinâmica crítica de modelos de spin, autômatos celulares e polipeptídeos. / Critical dynamics of spin models, cellular automata and polypeptides.
In this work we investigated dynamic properties of statistical mechanical models at criticality. At first, using the concepts of global persistence and anomalous dimension of initial magnetization, we showed that the Baxter-Wu model does not belong to the same universality class as 4-state Potts model and Ising with multispin interaction in one direction. In
Publicado em: 2005
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4. A thermodynamic model for the helix-coil transition coupled to dimerization of short coiled-coil peptides.
A simple thermodynamic formalism is presented to model the conformational transition between a random-coil monomeric peptide and a coiled-coil helical dimer. The coiled-coil helical dimer is the structure of a class of proteins also called leucine zipper, which has been studied intensively in recent years. Our model, which is appropriate particularly for sho
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5. Enthalpy of helix–coil transition: Missing link in rationalizing the thermodynamics of helix-forming propensities of the amino acid residues
It is known that different amino acid residues have effects on the thermodynamic stability of an α-helix. The underlying mechanism for the thermodynamic helical propensity is not well understood. The major accepted hypothesis is the difference in the side-chain configurational entropy loss upon helix formation. However, the changes in the side-chain configu
National Academy of Sciences.
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6. Rapid helix--coil transitions in the S-2 region of myosin.
Temperature-jump studies on the long S-2 fragment (100,000 daltons) isolated from myosin show that this structure can undergo alpha-helix--random coil transitions in a time range approximating the cycle time of a crossbridge. Two relaxation times are observed after temperature jumps of 5 degrees C over the range 35--55 degrees C, one in the submillisecond (t
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7. Nuclear magnetic resonance studies of the helix-coil transition of poly (dA-dT) in aqueous solution.
The well-resolved base and sugar proton resonances in the high resolution proton nuclear magnetic resonance (NMR) spectra of poly(dA-dT) can be monitored during the helix-coil transition. The observable resonances shift upfield on helix formation and the temperature-dependent chemical shifts exhibit a melting temperature t 1/2 = 69.9 +/- 0.3 degrees for 18.8
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8. Specific zinc-finger architecture required for HIV-1 nucleocapsid protein's nucleic acid chaperone function
The nucleocapsid protein (NC) of HIV type 1 (HIV-1) is a nucleic acid chaperone that facilitates the rearrangement of nucleic acid secondary structure during reverse transcription. HIV-1 NC contains two CCHC-type zinc binding domains. Here, we use optical tweezers to stretch single λ-DNA molecules through the helix-to-coil transition in the presence of wild
National Academy of Sciences.
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9. Thermodynamic parameters for the helix-coil transition of oligopeptides: molecular dynamics simulation with the peptide growth method.
The helix-coil transition equilibrium of polypeptides in aqueous solution was studied by molecular dynamics simulation. The peptide growth simulation method was introduced to generate dynamic models of polypeptide chains in a statistical (random) coil or an alpha-helical conformation. The key element of this method is to build up a polypeptide chain during t
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10. The helix-coil transition of closed and nicked DNAs in aqueous neutral trichloroacetate solutions.
The melting transition for closed, underwound DNAs and for nicked or linear DNAs was monitored by velocity sedimentation and by absorbance spectroscopy in aqueous NaCCl3CO2 (NaTCA) and RbTCA. The addition of neutral trichloroacetate lowers the midpoint of the helix-coil transition by 26% C/M for RbTCA and by 32% C/M for NaTCA, depressing the denaturation reg
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11. α-Helical stabilization by side chain shielding of backbone hydrogen bonds
We study atomic models of the thermodynamics of the structural transition of peptides that form α-helices. The effect of sequence variation on α-helix formation for alanine-rich peptides, Ac-Ala21- methyl amide (A21) and Ac-A5 (AAARA)3A-methyl amide (Fs peptide), is investigated by atomic simulation studies of the thermodynamics of the helix-coil transitio
The National Academy of Sciences.
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12. Molecular theory of the helix-coil transition in polyamino acids, I. Formulation.