Multisteric regulation by structural disorder in modular signaling proteins: An extension of the concept of allostery

Allostery is a classical regulatory mechanism of proteins in which a signal at 'another site' modifies the activity/function of a protein. In fact, with the recognition of the generality of the structural disorder of proteins and the landscape theory of protein structure, a 'new view' of allostery started to emerge, in which emphasis is placed on ligand-induced shifts in the conformational ensemble of the protein. The ensuing changes in ligand binding/catalytic activity might stem from coupled folding transitions of distinct binding sites or remodeling of the conformational landscape to entropically favor a particular downstream binding/catalytic event. The ensuing sigmoidal binding isotherm cannot be described by a simple saturation; rather, it shows signs of cooperation between ligands. If binding of one ligand weakens that of the others, one can also speak about negative cooperativity. To elucidate the underlying mechanistic changes, two models have been suggested, which, even today, form the basis of our textbook wisdom of this phenomenon

Exon-phase symmetry and intrinsic structural disorder promote modular evolution in the human genome

A key signature of module exchange in the genome is phase symmetry of exons, suggestive of exon shuffling events that occurred without disrupting translation reading frame. At the protein level, intrinsic structural disorder may be another key element because disordered regions often serve as functional elements that can be effectively integrated into a protein structure. Therefore, we asked whether exon-phase symmetry in the human genome and structural disorder in the human proteome are connected, signalling such evolutionary mechanisms in the assembly of multi-exon genes. We found an elevated level of structural disorder of regions encoded by symmetric exons and a preferred symmetry of exons encoding for mostly disordered regions (>70% predicted disorder). Alternatively spliced symmetric exons tend to correspond to the most disordered regions. The genes of mostly disordered proteins (>70% predicted disorder) tend to be assembled from symmetric exons, which often arise by internal tandem duplications. Preponderance of certain types of short motifs (e.g. SH3-binding motif) and domains (e.g. high-mobility group domains) suggests that certain disordered modules have been particularly effective in exon-shuffling events. Our observations suggest that structural disorder has facilitated modular assembly of complex genes in evolution of the human genome. © 2013 The Author(s)

A Kaqun víz hatása egészséges önkéntesek immunológiai paramétereire

Bevezetés: A Kaqun víz stabil, oldott formában tartalmaz nagy mennyiségű oxigént, amely a bőrön és emésztőrendszeren keresztül a szervezetbe jutva megemeli a szövetek oxigéntartalmát. Célkitűzés: A szerzők 21 napos Kaqun-terápia egészséges önkéntesek immunológiai paramétereire kifejtett hatásának vizsgálatát tűzték ki célul. Módszer: Immunfenotipizálással meghatározták a lymphocyta-alpopulációk arányát, CD25 és CD71 aktivációs antigénekkel felmérték a lymphocyták aktiváltságát, illetve megmérték a neutrophil granulocyták ölőképességével arányos reaktív oxigén intermedier termelést. Az adatokat ismételt méréses varianciaanalízissel elemezték. Eredmények: A neutrophil granulocyták reaktív oxigén intermedier termelése szignifikánsan nőtt a stimulált mintákban három hét Kaqun-kezelés alatt. Szintén emelkedett a CD25 aktivációs antigént kifejező T-, illetve helper T-lymphocyták százaléka, illetve az NK-sejtek aránya. Következtetések: A Kaqun-terápia által megemelt oldottoxigén-koncentráció számos immunológiai funkcióra hatással van: a neutrophil granulocyták ölőképességének fokozódását, a T-lymphocyták aktivációját, vagyis az immunválasz aktivitásának növekedését okozza, és növeli az NK-sejtek előfordulását, ami a vírussal fertőzött vagy tumoros sejtek elpusztítását segítheti el

Protein delivery into plant cells: Toward in vivo structural biology

Understanding the biologically relevant structural and functional behavior of proteins inside living plant cells is only possible through the combination of structural biology and cell biology. The state-of-the-art structural biology techniques are typically applied to molecules that are isolated from their native context. Although most experimental conditions can be easily controlled while dealing with an isolated, purified protein, a serious shortcoming of such in vitro work is that we cannot mimic the extremely complex intracellular environment in which the protein exists and functions. Therefore, it is highly desirable to investigate proteins in their natural habitat, i.e., within live cells. This is the major ambition of in-cell NMR, which aims to approach structure-function relationship under true in vivo conditions following delivery of labeled proteins into cells under physiological conditions. With a multidisciplinary approach that includes recombinant protein production, confocal fluorescence microscopy, nuclear magnetic resonance (NMR) spectroscopy and different intracellular protein delivery strategies, we explore the possibility to develop in-cell NMR studies in living plant cells. While we provide a comprehensive framework to set-up in-cell NMR, we identified the efficient intracellular introduction of isotope-labeled proteins as the major bottleneck. Based on experiments with the paradigmatic intrinsically disordered proteins (IDPs) Early Response to Dehydration protein 10 and 14, we also established the subcellular localization of ERD14 under abiotic stress. © 2017 Cedeño, Pauwels and Tompa