Search results for "proteiinit"
showing 10 items of 164 documents
Distribution and dynamics of transcription-associated proteins during parvovirus infection.
2012
Canine parvovirus (CPV) infection leads to reorganization of nuclear proteinaceous subcompartments. Our studies showed that virus infection causes a time-dependent increase in the amount of viral nonstructural protein NS1 mRNA. Fluorescence recovery after photobleaching showed that the recovery kinetics of nuclear transcription-associated proteins, TATA binding protein (TBP), transcription factor IIB (TFIIB), and poly(A) binding protein nuclear 1 (PABPN1) were different in infected and noninfected cells, pointing to virus-induced alterations in binding dynamics of these proteins. peerReviewed
Excitation-Wavelength Dependent Photocycle Initiation Dynamics Resolve Heterogeneity in the Photoactive Yellow Protein from Halorhodospira halophila
2018
Photoactive yellow proteins (PYPs) make up a diverse class of blue-light-absorbing bacterial photoreceptors. Electronic excitation of the p-coumaric acid chromophore covalently bound within PYP results in triphasic quenching kinetics; however, the molecular basis of this behavior remains unresolved. Here we explore this question by examining the excitation-wavelength dependence of the photodynamics of the PYP from Halorhodospira halophila via a combined experimental and computational approach. The fluorescence quantum yield, steady-state fluorescence emission maximum, and cryotrapping spectra are demonstrated to depend on excitation wavelength. We also compare the femtosecond photodynamics …
Sodium channels enable fast electrical signaling and regulate phagocytosis in the retinal pigment epithelium
2019
Background Voltage-gated sodium (Nav) channels have traditionally been considered a trademark of excitable cells. However, recent studies have shown the presence of Nav channels in several non-excitable cells, such as astrocytes and macrophages, demonstrating that the roles of these channels are more diverse than was previously thought. Despite the earlier discoveries, the presence of Nav channel-mediated currents in the cells of retinal pigment epithelium (RPE) has been dismissed as a cell culture artifact. We challenge this notion by investigating the presence and possible role of Nav channels in RPE both ex vivo and in vitro. Results Our work demonstrates that several subtypes of Nav cha…
Developing a matrix framework for protein transition towards more sustainable diets
2021
PurposeThe purpose of this study is to propose a matrix framework to understand the interdependencies of domains and scales of protein transition towards diets based on plants and alternative sources of proteins.Design/methodology/approachThe abductive research approach is used in building the framework, and the proposed framework is illustrated using the regional food system in Central Finland as an example. Focus groups and interviews were used to collect qualitative data from 28 respondents.FindingsThis study provides a framework for protein transition, with five domains and five scale levels. Interactions between public and private governance activities at different scales, domains and …
Potent Inhibitor of Human Trypsins from the Aeruginosin Family of Natural Products
2021
Funding Information: We would like to thank A. Löfhjelm and L. Saari for excellent technical assistance. This work was supported by a Sigrid Jusélius Foundation grant to H.K. and the Academy of Finland funding (321809) to T.S. We would also like to thank the Erkko Foundation and Nordforsk Nordic center of Excellency NordAqua (project number #82845) and University of Helsinki’s Doctoral Programme in Microbiology and Biotechnology funding to M.N.A. D.O.A. was supported by a postdoctoral research fellowship from the São Paulo Research Foundation (FAPESP #2018/01563-2). We thank Biocenter Kuopio for the use of their facilities for molecular modeling and MD simulations. We thank the DNA Sequenci…
Evolutionary plasticity of SH3 domain binding by Nef proteins of the HIV-1/SIVcpz lentiviral lineage
2021
The accessory protein Nef of human and simian immunodeficiency viruses (HIV and SIV) is an important pathogenicity factor known to interact with cellular protein kinases and other signaling proteins. A canonical SH3 domain binding motif in Nef is required for most of these interactions. For example, HIV-1 Nef activates the tyrosine kinase Hck by tightly binding to its SH3 domain. An archetypal contact between a negatively charged SH3 residue and a highly conserved arginine in Nef (Arg77) plays a key role here. Combining structural analyses with functional assays, we here show that Nef proteins have also developed a distinct structural strategy—termed the "R-clamp”—that favors the formation …
Functional roles of the membrane-associated AAV protein MAAP
2021
AbstractWith a limited coding capacity of 4.7 kb, adeno-associated virus (AAV) genome has evolved over-lapping genes to maximise the usage of its genome. An example is the recently found ORF in the cap gene, encoding membrane-associated accessory protein (MAAP), located in the same genomic region as the VP1/2 unique domain, but in a different reading frame. This 13 KDa protein, unique to the dependovirus genus, is not homologous to any known protein. Our studies confirm that MAAP translation initiates from the first CTG codon found in the VP1 ORF2. We have further observed MAAP localised in the plasma membrane, in the membranous structures in close proximity to the nucleus and to the nuclea…
Surface Characteristics Control the Attachment and Functionality of (Chimeric) Avidin
2018
The physical adsorption (physisorption) of proteins to surfaces is an important but incompletely understood factor in many biological processes and is of increasing significance in bionanotechnology as well. Avidin is an important protein because of strong avidin–biotin binding, which has been exploited in numerous applications. We have undertaken thorough experimentation on the physisorption of avidin, to chemically different flat surfaces of Si and graphite and also to the curved version of the latter, on multiwalled carbon nanotubes (MWNTs) of different diameters. The difference in the behavior of avidin on Si versus graphite is drastic; on Si, avidin deposits as single globular tetramer…
Myostatin and related proteins on the control of skeletal muscle mass and capillary density
2013
Skeletal muscle wasting is a feature of many pathological conditions such as muscular dystrophies, cancer and diabetes. Human ageing also results in the progressive loss of muscle mass and strength, a condition known as sarcopenia (or myopenia). Therefore, interventions that can reverse or slow down muscle loss are highly desirable. The TGF-β member myostatin is a well-known inhibitor of skeletal muscle growth, but it may also, if deleted, decrease muscle oxidative capacity. We have used the activin receptor 2B (ActR2B) fused to the Fc region of immunoglobulin G (ActR2B-Fc) as a trap to sequester myostatin and inhibit its activity. We sought to evaluate possible differences between doses an…
NMR structure of a non-conjugatable, ADP-ribosylation associated, ubiquitin-like domain from Tetrahymena thermophila polyubiquitin locus.
2019
Abstract Background Ubiquitin-like domains (UbLs), in addition to being post-translationally conjugated to the target through the E1-E2-E3 enzymatic cascade, can be translated as a part of the protein they ought to regulate. As integral UbLs coexist with the rest of the protein, their structural properties can differ from canonical ubiquitin, depending on the protein context and how they interact with it. In this work, we investigate T.th-ubl5, a UbL present in a polyubiquitin locus of Tetrahymena thermophila, which is integral to an ADP-ribosyl transferase protein. Only one other co-occurrence of these two domains within the same protein has been reported. Methods NMR, multiple sequence al…