scholarly journals NMR Mapping of Disordered Segments from a Viral Scaffolding Protein Encapsulated in a 23 MDa Procapsid Complex

2019 ◽  
Author(s):  
Richard D. Whitehead ◽  
Carolyn M. Teschke ◽  
Andrei T. Alexandrescu
Keyword(s):  
Structural Information ◽  
Scaffolding Protein ◽  
Coat Proteins ◽  
Scaffolding Proteins ◽  
Genome Packaging ◽  
C Terminus ◽  
Capsid Shell ◽  
N Terminus ◽  
Phage P22 ◽  
Nmr Signals

SummaryScaffolding proteins are requisite for the capsid shell assembly of many tailed dsDNA bacteriophages, some archaeal viruses, herpesviruses, and adenoviruses. Despite their importance, no high-resolution structural information is available for scaffolding proteins within capsids. Here we use the inherent size limit of NMR to identify mobile segments of the phage P22 scaffolding protein in solution and when incorporated into a ~23 MDa procapsid complex. Free scaffolding protein gives NMR signals from both the N and C-terminus. When scaffolding protein is incorporated into P22 procapsids, NMR signals from the C-terminal helix-turn-helix (HTH) domain disappear due to binding to the procapsid interior. Signals from the N-terminal domain persist, indicating this segment retains flexibility when bound to procapsids. The unstructured character of the N-terminus coupled with its high content of negative charges, is likely important for the dissociation and release of scaffolding protein, during the genome packaging step accompanying phage maturation.Graphical AbstractScaffolding protein (SP) nucleates the assembly of phage P22 coat proteins into an icosahedral capsid structure that envelops the viral genome. NMR spectra of free SP show signals from the N-terminus (red) and a helix-turn-helix domain at the C-terminus (blue). When SP is incorporated into empty phage P22 procapsids to form a 23 MDa complex, the subset of signals from the N-terminal 40 residues persist indicating this segment is disordered. The unfolded nature of the N-terminus coupled with its negatively charged character, is important for the functional requirement of SP to exit the capsid as it becomes packaged with its genome.

scholarly journals The Extracellular Transport Signal of the Vibrio cholerae Endochitinase (ChiA) Is a Structural Motif Located between Amino Acids 75 and 555

2002 ◽  
Vol 184 (8) ◽  
pp. 2225-2234 ◽  
Author(s):  
Jason P. Folster ◽  
Terry D. Connell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Vibrio Cholerae ◽  
Structural Information ◽  
Amino Acid Sequences ◽  
Structural Motif ◽  
Terminal Branch ◽  
C Terminus ◽  
N Terminus ◽  
Extracellular Transport

ABSTRACT ChiA, an 88-kDa endochitinase encoded by the chiA gene of the gram-negative enteropathogen Vibrio cholerae, is secreted via the eps-encoded main terminal branch of the general secretory pathway (GSP), a mechanism which also transports cholera toxin. To localize the extracellular transport signal of ChiA that initiates transport of the protein through the GSP, a chimera comprised of ChiA fused at the N terminus with the maltose-binding protein (MalE) of Escherichia coli and fused at the C terminus with a 13-amino-acid epitope tag (E-tag) was expressed in strain 569B(chiA::Kanr), a chiA-deficient but secretion-competent mutant of V. cholerae. Fractionation studies revealed that blockage of the natural N terminus and C terminus of ChiA did not prevent secretion of the MalE-ChiA-E-tag chimera. To locate the amino acid sequences which encoded the transport signal, a series of truncations of ChiA were engineered. Secretion of the mutant polypeptides was curtailed only when ChiA was deleted from the N terminus beyond amino acid position 75 or from the C terminus beyond amino acid 555. A mutant ChiA comprised of only those amino acids was secreted by wild-type V. cholerae but not by an epsD mutant, establishing that amino acids 75 to 555 independently harbored sufficient structural information to promote secretion by the GSP of V. cholerae. Cys77 and Cys537, two cysteines located just within the termini of ChiA(75-555), were not required for secretion, indicating that those residues were not essential for maintaining the functional activity of the ChiA extracellular transport signal.

scholarly journals Two Polo-like kinase 4 binding domains in Asterless perform distinct roles in regulating kinase stability

2015 ◽  
Vol 208 (4) ◽  
pp. 401-414 ◽  
Author(s):  
Joseph E. Klebba ◽  
Brian J. Galletta ◽  
Jonathan Nye ◽  
Karen M. Plevock ◽  
Daniel W. Buster ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Binding Domain ◽  
Terminal Region ◽  
Scaffolding Protein ◽  
Binding Partner ◽  
Centriole Duplication ◽  
Binding Domains ◽  
C Terminus ◽  
N Terminus

Plk4 (Polo-like kinase 4) and its binding partner Asterless (Asl) are essential, conserved centriole assembly factors that induce centriole amplification when overexpressed. Previous studies found that Asl acts as a scaffolding protein; its N terminus binds Plk4’s tandem Polo box cassette (PB1-PB2) and targets Plk4 to centrioles to initiate centriole duplication. However, how Asl overexpression drives centriole amplification is unknown. In this paper, we investigated the Asl–Plk4 interaction in Drosophila melanogaster cells. Surprisingly, the N-terminal region of Asl is not required for centriole duplication, but a previously unidentified Plk4-binding domain in the C terminus is required. Mechanistic analyses of the different Asl regions revealed that they act uniquely during the cell cycle: the Asl N terminus promotes Plk4 homodimerization and autophosphorylation during interphase, whereas the Asl C terminus stabilizes Plk4 during mitosis. Therefore, Asl affects Plk4 in multiple ways to regulate centriole duplication. Asl not only targets Plk4 to centrioles but also modulates Plk4 stability and activity, explaining the ability of overexpressed Asl to drive centriole amplification.

scholarly journals Coupling of microtubule motors with AP-3 generated organelles in axons by NEEP21 family member calcyon

2018 ◽  
Vol 29 (17) ◽  
pp. 2055-2068 ◽  
Author(s):  
Liang Shi ◽  
Timothy Hines ◽  
Clare Bergson ◽  
Deanna Smith
Keyword(s):  
Transmembrane Protein ◽  
Scaffolding Protein ◽  
Coat Proteins ◽  
Organelle Biogenesis ◽  
C Terminus ◽  
Microtubule Motors ◽  
Late Endosomes ◽  
Lysosome Related Organelles ◽  
Dependent Transport ◽  
The Brain

Transport of late endosomes and lysosome-related organelles (LE/LROs) in axons is essential for supplying synaptic cargoes and for removing damaged macromolecules. Defects in this system are implicated in a range of human neurodegenerative and neurodevelopmental disorders. The findings reported here identify a novel mechanism regulating LE/LRO transport based on the coordinated coupling of microtubule motors and vesicle coat proteins to the neuron-enriched, transmembrane protein calcyon (Caly). We found that the cytoplasmic C-terminus of Caly pulled down proteins involved in microtubule-dependent transport (DIC, KIF5A, p150Glued, Lis1) and organelle biogenesis (AP-1 and AP-3) from the brain. In addition, RNA interference–mediated knockdown of Caly increased the percentage of static LE/LROs labeled by LysoTracker in cultured dorsal root ganglion axons. In contrast, overexpression of Caly stimulated movement of organelles positive for LysoTracker or the AP-3 cargo GFP-PI4KIIα. However, a Caly mutant (ATEA) that does not bind AP-3 was unable to pull down motor proteins from brain, and expression of the ATEA mutant failed to increase either LE/LRO flux or levels of associated dynein. Taken together, these data support the hypothesis that Caly is a multifunctional scaffolding protein that regulates axonal transport of LE/LROs by coordinately interacting with motor and vesicle coat proteins.

scholarly journals ϕX174 Procapsid Assembly: Effects of an Inhibitory External Scaffolding Protein and Resistant Coat Proteins In Vitro

2016 ◽  
Vol 91 (1) ◽  
Author(s):  
James E. Cherwa ◽  
Joshua Tyson ◽  
Gregory J. Bedwell ◽  
Dewey Brooke ◽  
Ashton G. Edwards ◽  
...  
Keyword(s):  
Coat Protein ◽  
Experimental Evolution ◽  
Viral Fitness ◽  
Scaffolding Protein ◽  
Coat Proteins ◽  
Scaffolding Proteins ◽  
Biochemical Methods ◽  
Trade Offs

ABSTRACT During ϕX174 morphogenesis, 240 copies of the external scaffolding protein D organize 12 pentameric assembly intermediates into procapsids, a reaction reconstituted in vitro. In previous studies, ϕX174 strains resistant to exogenously expressed dominant lethal D genes were experimentally evolved. Resistance was achieved by the stepwise acquisition of coat protein mutations. Once resistance was established, a stimulatory D protein mutation that greatly increased strain fitness arose. In this study, in vitro biophysical and biochemical methods were utilized to elucidate the mechanistic details and evolutionary trade-offs created by the resistance mutations. The kinetics of procapsid formation was analyzed in vitro using wild-type, inhibitory, and experimentally evolved coat and scaffolding proteins. Our data suggest that viral fitness is correlated with in vitro assembly kinetics and demonstrate that in vivo experimental evolution can be analyzed within an in vitro biophysical context. IMPORTANCE Experimental evolution is an extremely valuable tool. Comparisons between ancestral and evolved genotypes suggest hypotheses regarding adaptive mechanisms. However, it is not always possible to rigorously test these hypotheses in vivo. We applied in vitro biophysical and biochemical methods to elucidate the mechanistic details that allowed an experimentally evolved virus to become resistant to an antiviral protein and then evolve a productive use for that protein. Moreover, our results indicate that the respective roles of scaffolding and coat proteins may have been redistributed during the evolution of a two-scaffolding-protein system. In one-scaffolding-protein virus assembly systems, coat proteins promiscuously interact to form heterogeneous aberrant structures in the absence of scaffolding proteins. Thus, the scaffolding protein controls fidelity. During ϕX174 assembly, the external scaffolding protein acts like a coat protein, self-associating into large aberrant spherical structures in the absence of coat protein, whereas the coat protein appears to control fidelity.

Preparation and properties of three analogues of [5-leucine]enkephalin, substrates for enzyme conversion studies

1985 ◽  
Vol 50 (6) ◽  
pp. 1329-1334
Author(s):  
Jaroslav Vičar ◽  
Linda Servítová ◽  
Martin Flegel ◽  
Karel Hauzer ◽  
Tomislav Barth
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Guinea Pig ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Guinea Pig Ileum ◽  
Opioid Activity ◽  
C Terminus ◽  
N Terminus ◽  
Fragment Condensation

Analogues of [5-Leu]enkephalin, prolonged by methionine on the N-terminus or, by lysine or methionine on the C-terminus were prepared by fragment condensation, purified by ion exchange chromatography or high-pressure liquid chromatography. The substances were characterised by their opioid activity in a test on guinea-pig ileum in comparison with the activity of [5-Leu]enkephalin.

scholarly journals Scaffolding proteins guide the evolution of algal light harvesting antennas

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Harry W. Rathbone ◽  
Katharine A. Michie ◽  
Michael J. Landsberg ◽  
Beverley R. Green ◽  
Paul M. G. Curmi
Keyword(s):  
Hydrophobic Surface ◽  
Scaffolding Protein ◽  
Secondary Endosymbiosis ◽  
Scaffolding Proteins ◽  
Α Subunit ◽  
Binding Partner ◽  
Photosynthetic Organisms ◽  
New Family ◽  
Red Algal ◽  
Multiple Copies

AbstractPhotosynthetic organisms have developed diverse antennas composed of chromophorylated proteins to increase photon capture. Cryptophyte algae acquired their photosynthetic organelles (plastids) from a red alga by secondary endosymbiosis. Cryptophytes lost the primary red algal antenna, the red algal phycobilisome, replacing it with a unique antenna composed of αβ protomers, where the β subunit originates from the red algal phycobilisome. The origin of the cryptophyte antenna, particularly the unique α subunit, is unknown. Here we show that the cryptophyte antenna evolved from a complex between a red algal scaffolding protein and phycoerythrin β. Published cryo-EM maps for two red algal phycobilisomes contain clusters of unmodelled density homologous to the cryptophyte-αβ protomer. We modelled these densities, identifying a new family of scaffolding proteins related to red algal phycobilisome linker proteins that possess multiple copies of a cryptophyte-α-like domain. These domains bind to, and stabilise, a conserved hydrophobic surface on phycoerythrin β, which is the same binding site for its primary partner in the red algal phycobilisome, phycoerythrin α. We propose that after endosymbiosis these scaffolding proteins outcompeted the primary binding partner of phycoerythrin β, resulting in the demise of the red algal phycobilisome and emergence of the cryptophyte antenna.

scholarly journals A Peptide-Nucleic Acid Targeting miR-335-5p Enhances Expression of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene with the Possible Involvement of the CFTR Scaffolding Protein NHERF1

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 117
Author(s):  
Anna Tamanini ◽  
Enrica Fabbri ◽  
Tiziana Jakova ◽  
Jessica Gasparello ◽  
Alex Manicardi ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Nucleic Acid ◽  
Peptide Nucleic Acid ◽  
Stop Codon ◽  
Scaffolding Protein ◽  
Cftr Gene ◽  
Scaffolding Proteins ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Cystic Fibrosis Transmembrane

(1) Background: Up-regulation of the Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) might be of great relevance for the development of therapeutic protocols for cystic fibrosis (CF). MicroRNAs are deeply involved in the regulation of CFTR and scaffolding proteins (such as NHERF1, NHERF2 and Ezrin). (2) Methods: Content of miRNAs and mRNAs was analyzed by RT-qPCR, while the CFTR and NHERF1 production was analyzed by Western blotting. (3) Results: The results here described show that the CFTR scaffolding protein NHERF1 can be up-regulated in bronchial epithelial Calu-3 cells by a peptide-nucleic acid (PNA) targeting miR-335-5p, predicted to bind to the 3′-UTR sequence of the NHERF1 mRNA. Treatment of Calu-3 cells with this PNA (R8-PNA-a335) causes also up-regulation of CFTR. (4) Conclusions: We propose miR-335-5p targeting as a strategy to increase CFTR. While the efficiency of PNA-based targeting of miR-335-5p should be verified as a therapeutic strategy in CF caused by stop-codon mutation of the CFTR gene, this approach might give appreciable results in CF cells carrying other mutations impairing the processing or stability of CFTR protein, supporting its application in personalized therapy for precision medicine.

scholarly journals Improved Antimicrobial Activities of Synthetic-Hybrid Bacteriocins Designed from Enterocin E50-52 and Pediocin PA-1

2014 ◽  
Vol 81 (5) ◽  
pp. 1661-1667 ◽  
Author(s):  
Santosh Kumar Tiwari ◽  
Katia Sutyak Noll ◽  
Veronica L. Cavera ◽  
Michael L. Chikindas
Keyword(s):  
Micrococcus Luteus ◽  
Electrical Potential ◽  
Gram Negative Bacteria ◽  
Additional Advantage ◽  
Gram Negative ◽  
Content Type ◽  
Intracellular Atp ◽  
Hybrid Peptides ◽  
C Terminus ◽  
N Terminus

ABSTRACTTwo hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64- and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8- and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wild-type (WT) bacteriocins on the transmembrane electrical potential (ΔΨ) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ΔΨ, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such asMicrococcus luteus,Salmonella entericaserovar Enteritidis 20E1090, andEscherichia coliO157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics.

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