Intramolecular Flexibility
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Estudos de macromoleculas biologicas parcialmente desestruturadas usando espalhamento de raios-X / Study of partially unstructured macromolecules using X-ray scattering
As técnicas de caracterização estrutural de macromoléculas tradicionais se baseiam no fato de uma macromolécula possuir uma conformação compacta e estruturada. Partes flexíveis ou regiões desordenadas têm sido sempre consideradas como grandes obstáculos para técnicas como a cristalografia de raios-X e a ressonância magnética nuclear (RMN). A ne
Publicado em: 2010
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2. Study of Adrenocorticotropic Hormone Conformation by Evaluation of Intramolecular Resonance Energy Transfer in Nε-Dansyllysine21-ACTH-(1-24)-Tetrakosipeptide
The solution conformation of ACTH was studied by intramolecular resonance energy transfer and fluorescence depolarization with the synthetic, biologically active, derivative Nε-dansyllysine21-ACTH-(1-24)-tetrakosipeptide. The Förster parameters involved in energy transfer from the donor Trp9 to the dansyl acceptor attached to the side chain of Lys21 were d
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3. FLEXIBILITY OF SUPPOSED “RIGID” MOLECULES: SUBSTITUTED 2,5-PIPERAZINEDIONES (DIKETOPIPERAZINES)
The relevant results of accurate X-ray analyses of both the trans-and the L-cis-3,6-dimethyl-2,5-piperazinediones (diketopiperazines) are reported. We note that a large variability of conformations for the ring system can be accomplished by coupling small bond-angle deformations with large variations of the internal rotation angles. The experimental molecula
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4. Bimodal activation of SMC ATPase by intra- and inter-molecular interactions
Structural maintenance of chromosomes (SMC) proteins play fundamental roles in higher-order chromosome dynamics from bacteria to humans. It has been proposed that the Bacillus subtilis SMC (BsSMC) homodimer is composed of two anti-parallel coiled-coil arms, each having an ATP-binding domain at its distal end. It remains totally unknown, however, how the two-
Oxford University Press.
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5. Control of gene expression by a mobile recombinational switch.
Transposable recombinational switches may play important roles in the evolution of bacterial populations by increasing flexibility in the control of expression of particular genes and thereby maintaining heterogeneity in clones of cells growing in a uniform environment. Experiments reported here show that Tn5-112, a deletion derivative of kanamycin-resistanc
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6. Molecular flexibility demonstrated by paramagnetic enhancements of nuclear relaxation. Application to alamethicin: a voltage-gated peptide channel.
A nitroxide spin label attached to the C-terminus of the channel forming peptide alamethicin produces an enhancement of the nuclear spin-lattice relaxation rates of peptide protons as a result of both intermolecular and intramolecular magnetic dipole-dipole interactions. The intermolecular contribution provides evidence that alamethicin monomers collide pref
The Biophysical Society.
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7. Aspartylglucosaminuria: cDNA encoding human aspartylglucosaminidase and the missense mutation causing the disease.
We have isolated a 2.1 kb cDNA which encodes human aspartylglucosaminidase (AGA, E.C. 3.5.1.26). The activity of this lysosomal enzyme is deficient in aspartylglucosaminuria (AGU), a recessively inherited lysosomal accumulation disease resulting in severe mental retardation. The polypeptide chain deduced from the AGA cDNA consists of 346 amino acids, has two
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8. The Length and Viscosity Dependence of End-to-End Collision Rates in Single-Stranded DNA
Intramolecular dynamics play an essential role in the folding and function of biomolecules and, increasingly, in the operation of many biomimetic technologies. Thus motivated we have employed both experiment and simulation to characterize the end-to-end collision dynamics of unstructured, single-stranded DNAs ranging from 6 to 26 bases. We find that, because
The Biophysical Society.
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9. Molecular rulers for measuring RNA structure: sites of crosslinking in chlorambucilyl-phenylalanyl-tRNAPhe (yeast) and chlorambucilyl-pentadecaprolyl-phenylalanyl-tRNAPhe (yeast) intramolecularly crosslinked in aqueous solution.
Intramolecular crosslinking of yeast phenylalanine tRNA in aqueous solution with rigid, variable-length crosslinking reagents, which we call "molecular rulers," has given results in reasonable agreement with the crystal structure. Chlorambucilyl-[3H]phenylalanyl-tRNAPhe crosslinked intramolecularly at G-71 and A-73, whereas chlorambucilyl-pentadecaprolyl-[3H
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10. The cysteine switch: a principle of regulation of metalloproteinase activity with potential applicability to the entire matrix metalloproteinase gene family.
The general applicability of the "cysteine-switch" activation mechanism to the members of the matrix metalloproteinase (MMP) gene family is examined here. All currently known members of the MMP gene family share the characteristic that they are synthesized in a latent, inactive, form. Recent evidence suggests that this latency in human fibroblast collagenase
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11. Consequences of amino acid insertions and/or deletions in transmembrane helix C of bacteriorhodopsin.
Six bacterioopsin mutants containing either single amino acid deletions (delta A84, delta L87), insertions (delta 85A, delta 88A), or both deletions and insertions (delta A84/delta 88A, delta 85A/delta L87) within the first two turns of transmembrane helix C, starting from the extracellular side, have been prepared. The mutant apoproteins refold in phospholi
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12. Helix bending in alamethicin: molecular dynamics simulations and amide hydrogen exchange in methanol.
Molecular dynamics simulations of alamethicin in methanol were carried out with either a regular alpha-helical conformation or the x-ray crystal structure as starting structures. The structures rapidly converged to a well-defined hydrogen-bonding pattern with mixed alpha-helical and 3(10)-helical hydrogen bonds, consistent with NMR structural characterizatio