Search results for "folding"

Structures of collagen IV globular domains: insight into associated pathologies, folding and network assembly. Corrigendum

2020

The article by Casino et al. [IUCrJ (2018). 5, 765–779] is corrected.

Probing a Polar Cluster in the Retinal Binding Pocket of Bacteriorhodopsin by a Chemical Design Approach

2012

Bacteriorhodopsin has a polar cluster of amino acids surrounding the retinal molecule, which is responsible for light harvesting to fuel proton pumping. From our previous studies, we have shown that threonine 90 is the pivotal amino acid in this polar cluster, both functionally and structurally. In an attempt to perform a phenotype rescue, we have chemically designed a retinal analogue molecule to compensate the drastic effects of the T90A mutation in bacteriorhodopsin. This analogue substitutes the methyl group at position C(13) of the retinal hydrocarbon chain by and ethyl group (20-methyl retinal). We have analyzed the effect of reconstituting the wild-type and the T90A mutant apoprotein…

Hepatitis B core particles as a universal display model: a structure-function basis for development

1999

AbstractBecause it exhibits a remarkable capability to accept mutational intervention and undergo correct folding and self-assembly in all viable prokaryotic and eukaryotic expression systems, hepatitis B core (HBc) protein has been favored over other proposed particulate carriers. Structurally, the unusual α-helical organization of HBc dimeric units allows introduction of foreign peptide sequences into several areas of HBc shells, including their most protruding spikes. Progress toward full resolution of the spatial structure as well as accumulation of chimeric HBc-based structures has brought closer the knowledge-based design of future vaccines, gene therapy tools and other artificial par…

Chaperones Involved in Hepatitis B Virus Morphogenesis

1999

Little is known about host cell factors necessary for hepatitis B virus (HBV) assembly which involves envelopment of cytosolic nucleocapsids by the S, M and L transmembrane viral envelope proteins and subsequent budding into intraluminal cisternae. Central to virogenesis is the L protein that mediates hepatocyte receptor binding and envelopment of capsids. To serve these topologically conflicting roles, L protein exhibits an unusual dual membrane topology, disposing its N-terminal preS domain inside and outside of the virion lipid envelope. The mixed topology is achieved by posttranslational preS translocation of about half of the L protein molecules across a post-endoplasmic reticulum memb…

Effect of a Rigid Sulfonamide Bond on Molecular Folding: A Case Study

2015

A disulfonamide compound with bulky aromatic side chains was prepared, and its properties as a potential building block for foldamers were evaluated. Two different solvate crystal forms of the compound were identified and compared to the structures of an analogous oligoamide and related disulfonamides. The disulfonamide is unfolded in one of the solvates, whereas in the other one, a loosely folded conformer stabilized by an intramolecular hydrogen bond is found. Density functional calculations indicated that the loosely folded conformer is slightly more stable than its unfolded isomer. The calculations also identified a third, more tightly folded and more extensively hydrogen bonded, confor…

Cryptogein affects expression of alpha3, alpha6 and beta1 20S proteasome subunits encoding genes in tobacco.

2001

Twelve a and b 20S proteasome subunits cDNAs showing 70–82% identity with the corresponding genes in Arabidopsis or rice, and features of eukaryotic proteasome subunits were cloned in tobacco. Only b1-tcI 7, a3 and a6, 20S proteasome subunits encoding genes were up-regulated by cryptogein, a proteinaceous elicitor of plant defence reactions. These results led to the hypothesis that the activation of b1-tcI 7, a3 and a6 could induce a specific proteolysis involved in the hypersensitive response and systemic acquired resistance monitored by cryptogein. In eukaryotes, the 26S proteasome is the central multicatalytic proteinase complex comprising two subcomplexes: the 20S core particle that per…

Molecular basis of filamin a-filGAP interaction and its impairment in congenital disorders associated with filamin a mutations

2008

Background Mutations in filamin A (FLNa), an essential cytoskeletal protein with multiple binding partners, cause developmental anomalies in humans. Methodology/Principal Findings We determined the structure of the 23rd Ig repeat of FLNa (IgFLNa23) that interacts with FilGAP, a Rac-specific GTPase-activating protein and regulator of cell polarity and movement, and the effect of the three disease-related mutations on this interaction. A combination of NMR structural analysis and in silico modeling revealed the structural interface details between the C and D β-strands of the IgFLNa23 and the C-terminal 32 residues of FilGAP. Mutagenesis of the predicted key interface residues confirmed the b…

HSP70 sequestration by free α-globin promotes ineffective erythropoiesis in β-thalassaemia

2014

International audience; β-Thalassaemia major (β-TM) is an inherited haemoglobinopathy caused by a quantitative defect in the synthesis of β-globin chains of haemoglobin, leading to the accumulation of free α-globin chains that form toxic aggregates. Despite extensive knowledge of the molecular defects causing β-TM, little is known of the mechanisms responsible for the ineffective erythropoiesis observed in the condition, which is characterized by accelerated erythroid differentiation, maturation arrest and apoptosis at the polychromatophilic stage. We have previously demonstrated that normal human erythroid maturation requires a transient activation of caspase-3 at the later stages of matur…

Structural Studies of Self-Folding Cavitands

2000

Tuen muodot ja oppimisen mahdollisuudet suomen kielen verkkokurssilla

2013

Tutkimuksessa tarkastellaan ulkomailla suomea opiskeleville suunniteltua A2–B1-tasoista verkkokurssia. Aineistona ovat kurssin osallistujien paivakirjamerkinnat, palautelomakkeet, viestit seka itse kurssi materiaaleineen. Verkkokurssia analysoidaan ekologisessa viitekehyksessa opiskelijoiden kokeman tuen seka affordanssin kasitteiden kautta. Tuloksista kay ilmi, etta kurssilla on runsaasti mahdollisuuksia vastavuoroiseen vertaistukeen. Ohjaajan antamaksi tueksi oppijat mieltavat erityisesti kurssin alussa kielen rakennetta ja sanastoa koskevan palautteen ja niihin liittyvat tehtavat. Affordanssiksi oppijoiden nakokulmasta nousevat sanasto, kielen rakenteeseen liittyvat ilmiot seka kulttuuri…