Search results for "folding"

Mācību modelis WebQuest augstāko domāšanas prasmju pilnveides atbalstam 11. klases biznesa angļu valodas stundās

2017

Skolas vadība motivēja Diplomdarba autoru mācību laikā izmantot modernās tehnoloģijas, bet darba autoram bija grūtības atrast jēgpilnu veidu kā tās iekļaut ikdienas mācību stundās. Tajā pat laikā, tika novērots, ka skolēniem ir grūtības pielietot augstākās domāšanas prasmes stundās. Lai risinātu augstāk minētās problēmas tika nolemts pielietot mācību modeli WebQuest augstāko domāšanas prasmju pilnveides atbalstam. Pētījuma metode bija gadījuma pētījums Babītes vidusskolā no 2016. gada septembra līdz 2016. gada decembrim un tajā piedalījās trīspadsmit 11. klases skolēni. Pētījuma laikā tika analizēts biznesa angļu valodas standarts, izstrādāta anketa skolēniem, kuru viņi aizpildīja, izveidot…

The role of hydrophobic matching on transmembrane helix packing in cells

2017

Folding and packing of membrane proteins are highly influenced by the lipidic component of the membrane. Here, we explore how the hydrophobic mismatch (the difference between the hydrophobic span of a transmembrane protein region and the hydrophobic thickness of the lipid membrane around the protein) influences transmembrane helix packing in a cellular environment. Using a ToxRED assay in Escherichia coli and a Bimolecular Fluorescent Complementation approach in human-derived cells complemented by atomistic molecular dynamics simulations we analyzed the dimerization of Glycophorin A derived transmembrane segments. We concluded that, biological membranes can accommodate transmembrane homo-di…

Il destino delle catene polipeptidiche dalla sintesi fino alla maturazione: una panoramica

2011

Chromatin Domains and Regulation of Transcription

2007

Compartmentalization and compaction of DNA in the nucleus is the characteristic feature of eukaryotic cells. A fully extended DNA molecule has to be compacted 100,000 times to fit within the nucleus. At the same time it is critical that various DNA regions remain accessible for interaction with regulatory factors and transcription/replication factories. This puzzle is solved at the level of DNA packaging in chromatin that occurs in several steps: rolling of DNA onto nucleosomes, compaction of nucleosome fiber with formation of the so-called 30 nm fiber, and folding of the latter into the giant (50-200 kbp) loops, fixed onto the protein skeleton, the nuclear matrix. The general assumption is…

Human Hsp10 and Early Pregnancy Factor (EPF) and their relationship and involvement in cancer and immunity: current knowledge and perspectives.

2009

This article is about Hsp10 and its intracellular and extracellular forms focusing on the relationship of the latter with Early Pregnancy Factor and on their roles in cancer and immunity. Cellular physiology and survival are finely regulated and depend on the correct functioning of the entire set of proteins. Misfolded or unfolded proteins can cause deleterious effects and even cell death. The chaperonins Hsp10 and Hsp60 act together inside the mitochondria to assist protein folding. Recent studies demonstrated that these proteins have other roles inside and outside the cell, either together or independently of each other. For example, Hsp10 was found increased in the cytosol of different t…

Perturbations of symmetric elliptic Hamiltonians of degree four

2006

AbstractIn this paper four-parameter unfoldings Xλ of symmetric elliptic Hamiltonians of degree four are studied. We prove that in a compact region of the period annulus of X0 the displacement function of Xλ is sign equivalent to its principal part, which is given by a family induced by a Chebychev system; and we describe the bifurcation diagram of Xλ in a full neighborhood of the origin in the parameter space, where at most two limit cycles can exist for the corresponding systems.

Site-Specific Information on Membrane Protein Folding by Electron Spin Echo Envelope Modulation Spectroscopy

2010

Compared to folding of soluble proteins, folding of membrane proteins is complicated by the fact that it requires an amphiphilic environment. Few existing techniques can provide structurally resolved information on folding kinetics. For the major plant light harvesting complex LHCII, it is demonstrated that changes in water accessibility of a particular amino acid residue can be followed during folding by measuring the hyperfine interaction of spin labels with deuterium nuclei of heavy water. The incorporation of residue 196 into the hydrophobic core of a detergent micelle was investigated. The technique provides a time constant that is similar to the one found with fluorescence spectroscop…

Folding in vitro of light-harvesting chlorophyll a/b protein is coupled with pigment binding.

2002

The major light-harvesting chlorophyll a/b protein (LHCIIb) of the plant photosynthetic apparatus is able to self-organise in vitro. When the recombinant apoprotein, Lhcb1, is solubilised in the denaturing detergent sodium (or lithium) dodecylsulfate (SDS or LDS) and then mixed with chlorophylls and carotenoids under renaturing conditions, structurally authentic LHCIIb forms. Assembly of functional LHCIIb, as indicated by the establishment of energy transfer between complex-bound chlorophyll molecules, occurs in two apparent kinetic steps with time constants of 10 to 30 seconds and 50 to 300 seconds, depending on the reaction conditions. Here, we use circular dichroism (CD) in the far-UV ra…

Random mutations directed to transmembrane and loop domains of the light-harvesting chlorophyll a/b protein: impact on pigment binding.

1999

The major light-harvesting complex of photosystem II (LHCII) can be reconstituted in vitro by folding its bacterially expressed apoprotein, Lhcb, in detergent solution in the presence of chlorophylls and carotenoids. To compare the impact of alpha-helical transmembrane domains and hydrophilic loop domains of the apoprotein on complex formation and stability, we introduced random mutations into a segment of the protein comprising the stromal loop, the third (C-proximal) transmembrane helix, and part of the amphipathic helix in the C-terminal domain. The mutant versions of Lhcb were screened for the loss of their ability to form stable LHCII upon reconstitution in vitro. Most steps during the…

Decreasing the chlorophyll a/b ratio in reconstituted LHCII: Structural and functional consequences

1999

Trimeric (bT) and monomeric (bM) light-harvesting complex II (LHCII) with a chlorophyll a/b ratio of 0.03 were reconstituted from the apoprotein overexpressed in Escherichia coli. Chlorophyll/xanthophyll and chlorophyll/protein ratios of bT complexes and 'native' LHCII are rather similar, namely, 0.28 vs 0. 27 and 10.5 +/- 1.5 vs 12, respectively, indicating the replacement of most chlorophyll a molecules with chlorophyll b, leaving one chlorophyll a per trimeric complex. The LD spectrum of the bT complexes strongly suggests that the chlorophyll b molecules adopt orientations similar to those of the chlorophylls a that they replace. The circular dichroism (CD) spectra of bM and bT complexes…