Read by QxMD icon Read

Unstructured Proteins

Sarah L Rouse, Wlliam J Hawthorne, Sebastian Lambert, Marc L Morgan, Stephen A Hare, Stephen Matthews
Bacteria often produce extracellular amyloid fibres via a multi-component secretion system. Aggregation-prone, unstructured subunits cross the periplasm and are secreted through the outer membrane, after which they self-assemble. Here, significant progress is presented towards solving the high-resolution crystal structure of the novel amyloid transporter FapF from Pseudomonas, which facilitates the secretion of the amyloid-forming polypeptide FapC across the bacterial outer membrane. This represents the first step towards obtaining structural insight into the products of the Pseudomonas fap operon...
December 1, 2016: Acta Crystallographica. Section F, Structural Biology Communications
Chunling Dong, Peng Yan, Juxun Wang, Hailian Mu, Shuli Wang, Fangchun Guo
The oncogenic transcription factor forkhead box M (Foxm) is overexpressed in human colorectal cancer (CRC). Targeting the protein interaction with its cognate DNA has been established as an attractive approach to anti-CRC chemotherapy. State-of-the-art molecular dynamics (MD) simulations revealed that the Foxm adopts considerably different conformations to interact with and without its DNA partner; the holo conformation is tightly packed as a typical globulin configuration, whereas the apo form is locally unstructured that exhibits intrinsic disorder in DNA recognition helix, indicating that DNA binding can help the Foxm refolding...
November 9, 2016: Bioorganic Chemistry
Theo Luiz Ferraz de Souza, Sheila Maria Barbosa de Lima, Vanessa L de Azevedo Braga, David S Peabody, Davis Fernandes Ferreira, M Lucia Bianconi, Andre Marco de Oliveira Gomes, Jerson Lima Silva, Andréa Cheble de Oliveira
BACKGROUND: Hepatitis C virus (HCV) core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124) is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs) in vitro. The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood...
2016: PeerJ
Benjamin Pillet, Valentin Mitterer, Dieter Kressler, Brigitte Pertschy
Eukaryotic ribosomes are assembled from their components, the ribosomal RNAs and ribosomal proteins, in a tremendously complex, multi-step process, which primarily takes place in the nuclear compartment. Therefore, most ribosomal proteins have to travel from the cytoplasm to their incorporation site on pre-ribosomes within the nucleus. However, due to their particular characteristics, such as a highly basic amino acid composition and the presence of unstructured extensions, ribosomal proteins are especially prone to aggregation and degradation in their unassembled state, hence specific mechanisms must operate to ensure their safe delivery...
November 17, 2016: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Jean-François Millau, Benoit Guillemette, Luc Gaudreau
In this chapter we present a method allowing the screening of random sequences to discover essential aspects of unstructured protein regions in yeast. The approach can be applied to any protein with unstructured peptide sequences for which functions are difficult to decipher, for example the N-terminal tails of histones. The protocol first describes the building and preparation of a large library of random peptides in fusion with a protein of interest. Recent technical advances in oligonucleotide synthesis allow the construction of long random sequences up to 35 residues long...
2017: Methods in Molecular Biology
Daniel N Clark, John M Flanagan, Jianming Hu
: Hepatitis B virus (HBV) encodes a multi-function reverse transcriptase or polymerase (P), which is composed of several domains. The terminal protein (TP) domain is unique to HBV and related Hepadnaviruses and is required for specifically binding to the viral pregenomic RNA (pgRNA). Subsequently, the TP domain is necessary for pgRNA packaging into viral nucleocapsids and the initiation of viral reverse transcription for conversion of the pgRNA to viral DNA. Uniquely, the HBV P protein initiates reverse transcription via a protein priming mechanism using the TP domain as a primer...
November 16, 2016: Journal of Virology
Juan Mucci, Andrés B Lantos, Carlos A Buscaglia, María Susana Leguizamón, Oscar Campetella
The Trypanosoma cruzi trypomastigote membrane provides a major protective role against mammalian host-derived defense mechanisms while allowing the parasite to interact with different cell types and trigger pathogenesis. This surface has been historically appreciated as a rather unstructured 'coat', mainly consisting of a continuous layer of glycolipids and heavily O-glycosylated mucins, occasionally intercalated with different developmentally regulated molecules displaying adhesive and/or enzymatic properties...
November 11, 2016: Trends in Parasitology
Julia Hahn, Sebastian Thalmann, Anzhela Migur, Raphael Freiherr von Boeselager, Nina Kubatova, Elena Kubareva, Harald Schwalbe, Elena Evguenieva-Hackenberg
Up to now, very small protein-coding genes have remained unrecognized in sequenced genomes. We identified an mRNA of 165 nucleotides (nt), which is conserved in Bradyrhizobiaceae and encodes a polypeptide with 14 amino acid residues (aa). The small mRNA harboring a unique Shine-Dalgarno sequence (SD) with a length of 17 nt was localized predominantly in the ribosome-containing P100 fraction of Bradyrhizobium japonicum USDA 110. Strong interaction between the mRNA and 30S ribosomal subunits was demonstrated by their co-sedimentation in sucrose density gradient...
November 11, 2016: RNA Biology
Julia Muenzner, Linton M Traub, Bernard T Kelly, Stephen C Graham
Short peptide motifs in unstructured regions of clathrin-adaptor proteins recruit clathrin to membranes to facilitate post-Golgi membrane transport. Three consensus clathrin-binding peptide sequences have been identified and structural studies show that each binds distinct sites on the clathrin heavy chain N-terminal domain (NTD). A fourth binding site for adaptors on NTD has been functionally identified but not structurally characterised. We have solved high resolution structures of NTD bound to peptide motifs from the cellular clathrin adaptors β2 adaptin and amphiphysin plus a putative viral clathrin adaptor, hepatitis D virus large antigen (HDAg-L)...
November 3, 2016: Traffic
Per Eugen Kristiansen, Cecilia Persson, Virginia Fuochi, Anders Pedersen, Göran B Karlsson, Jon Nissen-Meyer, Camilla Oppegård
The class IId bacteriocin lactococcin A and the pediocin-like bacteriocins induce membrane leakage and cell death by specifically binding the mannose phophotransferase system (man-PTS) on their target cells. The bacteriocins' cognate immunity proteins that protect the producer cell from its own bacteriocin recognize and bind to the bacteriocin-man-PTS complex and thereby block membrane leakage. In this study, we have determined the three-dimensional structure of the lactococcin A immunity protein (LciA) by the use of nuclear magnetic resonance spectroscopy...
November 3, 2016: Biochemistry
Christopher McDonald, Goran Jovanovic, B A Wallace, Oscar Ces, Martin Buck
The phage shock protein (Psp) response maintains integrity of the inner membrane (IM) in response to extracytoplasmic stress conditions and is widely distributed amongst enterobacteria. Its central component PspA, a member of the IM30 peripheral membrane protein family, acts as a major effector of the system through its direct association with the IM. Under non-stress conditions PspA also negatively regulates its own expression via direct interaction with the AAA+ ATPase PspF. PspA has a counterpart in cyanobacteria called Vipp1, which is implicated in protection of the thylakoid membranes...
October 30, 2016: Biochimica et Biophysica Acta
Sukanya Sasmal, Nadine Schwierz, Teresa Head-Gordon
In this work we characterize the nucleation and elongation mechanisms of the "diseased" polymorph of the amyloid-β 40 fibril by using an off-lattice coarse-grained (CG) protein model. After determining the nucleation size and subsequent stable protofibrillar structure from the CG model, validated with all-atom simulations, we consider the "lock and dock" and "activated monomer" fibril elongation mechanisms for the protofibril by the statistical additions of a monomer drawn from four different ensembles of the free amyloid-β 40 peptide to grow the fibril...
November 2, 2016: Journal of Physical Chemistry. B
Jean Merone, Onyekahi Nwogu, Jennifer M Redington, Vladimir N Uversky
Sex differentiation is a complex process where sexually indifferent embryo progressively acquires male or female characteristics via tightly controlled, perfectly timed, and sophisticatedly intertwined chain of events. This process is controlled and regulated by a set of specific proteins, with one of the first steps in sex differentiation being the activation of the Y-chromosomal Sry gene (sex-determining region Y) in males that acts as a switch from undifferentiated gonad somatic cells to testis development...
October 28, 2016: Current Protein & Peptide Science
Ryan L Melvin, Ryan C Godwin, Jiajie Xiao, William G Thompson, Kenneth S Berenhaut, Freddie R Salsbury
As the length of molecular dynamics (MD) trajectories grows with increasing computational power, so does the importance of clustering methods for partitioning trajectories into conformational bins. Of the methods available, the vast majority require users to either have some \textit{a priori} knowledge about the system to be clustered or to tune clustering parameters through trial and error. Here we present non-parametric uses of two modern clustering techniques suitable for first-pass investigation of an MD trajectory...
November 1, 2016: Journal of Chemical Theory and Computation
Sarah J Smith, Robert J Radford, Rohit H Subramanian, Brandon R Barnett, Joshua S Figueroa, F Akif Tezcan
Given the prevalent role of α-helical motifs on protein surfaces in mediating protein-protein and protein-DNA interactions, there have been significant efforts to develop strategies to induce α-helicity in short, unstructured peptides to interrogate such interactions. Toward this goal, we have recently introduced hybrid metal coordination motifs (HCMs). HCMs combine a natural metal-binding amino acid side chain with a synthetic chelating group that are appropriately positioned in a peptide sequence to stabilize an α-helical conformation upon metal coordination...
August 1, 2016: Chemical Science
Søren B van Witteloostuijn, Søren L Pedersen, Knud J Jensen
Peptides and proteins constitute a vast pool of excellent drug candidates. Evolution has equipped these molecules with superior drug-like properties such as high specificity and potency. However, native peptides and proteins suffer from an inadequate pharmacokinetic profile, and their outstanding pharmacological potential can only be realized if this issue is addressed during drug development. To overcome this challenge, a variety of half-life extension techniques relying on covalent chemical modification have been developed...
November 21, 2016: ChemMedChem
Alexander K C Ulrich, Martin Seeger, Tonio Schütze, Natascha Bartlick, Markus C Wahl
The spliceosomal B complex-specific protein Prp38 forms a complex with the intrinsically unstructured proteins MFAP1 and Snu23. Our binding and crystal structure analyses show that MFAP1 and Snu23 contact Prp38 via ER/K motif-stabilized single α helices, which have previously been recognized only as rigid connectors or force springs between protein domains. A variant of the Prp38-binding single α helix of MFAP1, in which ER/K motifs not involved in Prp38 binding were mutated, was less α-helical in isolation and showed a reduced Prp38 affinity, with opposing tendencies in interaction enthalpy and entropy...
October 13, 2016: Structure
Masayuki Onishi, John R Pringle
The unicellular green alga Chlamydomonas reinhardtii is a model organism that provides an opportunity to understand the evolution and functional biology of the lineage that includes the land plants, as well as aspects of the fundamental core biology conserved throughout the eukaryotic phylogeny. Although many tools are available to facilitate genetic, molecular biological, biochemical, and cell biological studies in Chlamydomonas, expression of unselected transgenes of interest (GOIs) has been challenging. In most methods used previously, the GOI and a selectable marker are expressed from two separate mRNAs, so that their concomitant expression is not guaranteed...
October 21, 2016: G3: Genes—Genomes—Genetics
Jenna F DuMond, Xue Zhang, Yuichiro Izumi, Kevin Ramkissoon, Guanghui Wang, Marjan Gucek, Xujing Wang, Maurice B Burg, Joan D Ferraris
NFAT5 is a transcription factor originally identified because it is activated by hypertonicity and that activation increases expression of genes that protect against the adverse effects of the hypertonicity. However, its targets also include genes not obviously related to tonicity. The transactivating domain of NFAT5 is contained in its c-terminal region, which is predicted to be unstructured. Unstructured regions are common in transcription factors particularly in transactivating domains where they can bind co-regulatory proteins essential to their function...
October 7, 2016: Physiological Genomics
Christoph Göbl, Moritz Resch, Madeleine Strickland, Christoph Hartlmüller, Martin Viertler, Nico Tjandra, Tobias Madl
The study of intrinsically disordered proteins (IDPs) by NMR often suffers from highly overlapped resonances that prevent unambiguous chemical-shift assignments, and data analysis that relies on well-separated resonances. We present a covalent paramagnetic lanthanide-binding tag (LBT) for increasing the chemical-shift dispersion and facilitating the chemical-shift assignment of challenging, repeat-containing IDPs. Linkage of the DOTA-based LBT to a cysteine residue induces pseudo-contact shifts (PCS) for resonances more than 20 residues from the spin-labeling site...
November 14, 2016: Angewandte Chemie
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"