Supramolecular dimerization of a hexameric hemoprotein via multiple pyrene-pyrene interactions

2020 ◽  
Vol 24 (01n03) ◽  
pp. 259-267 ◽  
Author(s):  
Koji Oohora ◽  
Shota Hirayama ◽  
Tsuyoshi Mashima ◽  
Takashi Hayashi
Keyword(s):  
Supramolecular Assembly ◽  
Size Exclusion ◽  
Bottom Surface ◽  
Stacking Interactions ◽  
Protein Assemblies ◽  
New Class ◽  
Exclusion Chromatography ◽  
A Site ◽  
Subsequent Addition ◽  
Multivalent Effect

Protein assemblies are being investigated as a new-class of biomaterials. A supramolecular assembly of a mutant hexameric tyrosine coordinated hemoprotein (HTHP) modified with a pyrene derivative is described. Cysteine was first introduced as a site-specific reaction point at position V44 which is located at the bottom surface of the cylindrical structure of HTHP. [Formula: see text]-(1-pyrenyl)maleimide was then reacted with the mutant. The modification was confirmed by MALDI-TOF mass spectrometry and UV-vis absorption spectroscopy, indicating that approximately 90% cysteine residues are attached via the pyrene derivative. Size exclusion chromatography (SEC) measurements for pyrene-attached HTHP include a single peak which elutes earlier than the unmodified HTHP. Further investigation by SEC and dynamic light scattering (DLS) measurements indicate the desired size corresponding to the dimer of the hemoprotein hexamers. The multivalent effect of pyrene–pyrene interactions including hydrophobic and [Formula: see text]–[Formula: see text] stacking interactions appears to be responsible for including formation of the stable dimer of the hexamers. Interestingly, the assembly dissociates to the hexamer by removal of heme. In the case of the apo-form of pyrene-attached HTHP, the pyrene moiety appears to be incorporated into the heme pocket because the modification point is located at the adjacent residue of the Tyr45 coordinating to heme in the holo-form of HTHP. Subsequent addition of heme into the apo-form of pyrene-attached HTHP regenerates the dimer of the hexamers. The present study demonstrates a unique heme-dependent system in which HTHP is assembled to form a dimer of hexamers in the presence of heme and disassembled by removal of heme.

scholarly journals A Supramolecular Assembly of Hemoproteins Formed in a Star-Shaped Structure via Heme–Heme Pocket Interactions

2021 ◽  
Vol 22 (3) ◽  
pp. 1012
Author(s):  
Julian Wong Soon ◽  
Koji Oohora ◽  
Shota Hirayama ◽  
Takashi Hayashi
Keyword(s):  
Supramolecular Assembly ◽  
Building Blocks ◽  
Size Exclusion ◽  
Hydrodynamic Diameter ◽  
Prosthetic Group ◽  
Heme Pocket ◽  
Cytochrome B562 ◽  
Sds Page ◽  
Vis Spectroscopy ◽  
Exclusion Chromatography

Proteins have been used as building blocks to provide various supramolecular structures in efforts to develop nano-biomaterials possessing broad biological functionalities. A series of unique structures have been obtained from the engineering of hemoproteins which contain the iron porphyrin known as heme, as a prosthetic group. This work in developing assembling systems is extended using cytochrome b562, a small electron transfer hemoprotein engineered to include an externally-attached heme moiety. The engineered units, which form a one-dimensional assembly via interprotein heme–heme pocket interactions, are conjugated to an apo-form of hexameric tyrosine-coordinated hemoprotein (apoHTHP) to provide a branching unit promoting the assembly of a star-shaped structure. The incorporation of the heme moiety attached to the protein surface of cytochrome b562 into apoHTHP can be accelerated by elevating the reaction temperature to generate a new assembly. The formation of a new larger assembly structure was confirmed by size exclusion chromatography. The ratio of the heme-containing units in the assemblies was analyzed by UV-Vis spectroscopy and the population of protein units estimated from SDS PAGE suggests the presence of plausible star-shaped structures, which are supported by hydrodynamic diameter data obtained by dynamic light scattering.

scholarly journals Supramolecular assembly of a phosphole-based moiety into nanostructures dictated by alkynylplatinum(ii) terpyridine complexes through non-covalent Pt⋯Pt and π–π stacking interactions: synthesis, characterization, photophysics and self-assembly behaviors

2017 ◽  
Vol 8 (6) ◽  
pp. 4264-4273 ◽  
Author(s):  
Sammual Yu-Lut Leung ◽  
Sloane Evariste ◽  
Christophe Lescop ◽  
Muriel Hissler ◽  
Vivian Wing-Wah Yam
Keyword(s):  
Self Assembly ◽  
Supramolecular Assembly ◽  
Stacking Interactions ◽  
New Class ◽  
Π Stacking

A new class of platinum(ii) terpyridine complexes with a phosphole-derived bridging alkynyl ligand have been prepared.

scholarly journals Seed-competent tau monomer initiates pathology in PS19 tauopathy mice

2022 ◽  
Author(s):  
Hilda Mirbaha ◽  
Dailu Chen ◽  
Vishruth Mullapudi ◽  
Sandi Jo Estill Terpack ◽  
Charles L. White ◽  
...  
Keyword(s):  
Mouse Model ◽  
Biologically Active ◽  
Size Exclusion ◽  
Protein Assemblies ◽  
Post Translational Modifications ◽  
Conformational Ensembles ◽  
Insoluble Material ◽  
Repeat Domain ◽  
Exclusion Chromatography ◽  
Tau Aggregation

Tau aggregation into ordered assemblies causes myriad neurodegenerative tauopathies. We previously reported that tau monomer exists in either inert (Mi) or seed-competent (Ms) conformational ensembles, and that Ms encodes strains, which are biologically active, self-propagating assemblies. We have previously isolated Ms from tauopathy brains, but it is unknown if disease begins with Ms formation followed by fibril assembly, or if Ms derives from fibrils and is an epiphenomenon. Consequently, we studied a tauopathy mouse model (PS19) that expresses full-length human (1N4R) tau containing a disease-associated mutation (P301S). Using tau repeat domain biosensor cells, we detected insoluble tau seeding activity at 2 months. We found insoluble tau protein assemblies by immunoblot at 3 months. We next immunopurified monomer from mice aged 1-6 weeks using size exclusion chromatography. We detected soluble seeding activity at 4 weeks, before insoluble material or larger assemblies, with assemblies ranging from n=1-3 tau units. By 5 and 6 weeks, large soluble assemblies had formed. This indicated the first detectable pathological forms of tau were Ms. We next tested for post-translational modifications of tau monomer from 1-6 weeks. We detected no phosphorylation unique to Ms in PS19 or Alzheimer disease brain. We conclude that tauopathy begins with formation of Ms monomer, whose activity is phosphorylation-independent. Ms self-assembles to form oligomers before it forms insoluble fibrils. The conversion of tau monomer from Mi to Ms thus constitutes the first detectable step in the initiation of tauopathy in this mouse model, with obvious implications for origins of disease in humans.

scholarly journals Poly(vinyl amine) as a matrix for a new class of polymers

e-Polymers ◽  
2018 ◽  
Vol 18 (4) ◽  
pp. 347-357 ◽  
Author(s):  
Stanislav N. Zelinskiy ◽  
Elena N. Danilovtseva ◽  
Gayathri Kandasamy ◽  
Viktor A. Pal’shin ◽  
Tatyana A. Shishlyannikova ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Main Chain ◽  
Size Exclusion ◽  
Composite Nanoparticles ◽  
New Class ◽  
Dna And Rna ◽  
Mass Fractions ◽  
Exclusion Chromatography ◽  
Amine Groups

AbstractPoly(vinyl amine) was utilized as a matrix for the synthesis of polymers bearing short polyamine chains (1–3 amine groups) grafted to the main macromolecular chain with long (eight atoms) spacers. The new polymers were characterized with nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, size exclusion chromatography and potentiometry. Poly(vinyl amine) was applied in the form of narrow molecular mass fractions and the modification proceeded without destruction of the main chain. Condensation of silicic acid in the presence of the polymeric amines gives rise to composite nanoparticles which are stable in aqueous medium. New polymers and composite nanoparticles effectively complex with DNA and RNA oligonucleotides and were found to display good internalization in cancer cells which indicates their promise towards gene delivery applications.

CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  
Keyword(s):  
Modifier Gene ◽  
Size Exclusion ◽  
Plasma Lipoproteins ◽  
Lipoprotein Profile ◽  
Exclusion Chromatography ◽  
Low Hdl ◽  
Lcat Deficiency ◽  
Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

Structure of a shear-thickening polysaccharide extracted from the New Zealand black tree fern, Cyathea medullaris

2020 ◽  
Author(s):  
M Wee ◽  
M Mastrangelo ◽  
Susan Carnachan ◽  
Ian Sims ◽  
K Goh
Keyword(s):  
New Zealand ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Shear Thickening ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Tree Fern ◽  
13C Nuclear Magnetic Resonance ◽  
Exclusion Chromatography

A shear-thickening water-soluble polysaccharide was purified from mucilage extracted from the fronds of the New Zealand black tree fern (Cyathea medullaris or 'mamaku' in Māori) and its structure characterised. Constituent sugar analysis by three complementary methods, combined with linkage analysis (of carboxyl reduced samples) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR) revealed a glucuronomannan comprising a backbone of 4-linked methylesterified glucopyranosyl uronic acid and 2-linked mannopyranosyl residues, branched at O-3 of 45% and at both O-3 and O-4 of 53% of the mannopyranosyl residues with side chains likely comprising terminal xylopyranosyl, terminal galactopyranosyl, non-methylesterified terminal glucopyranosyl uronic acid and 3-linked glucopyranosyl uronic acid residues. The weight-average molecular weight of the purified polysaccharide was ~1.9×106Da as determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS). The distinctive rheological properties of this polysaccharide are discussed in relation to its structure. © 2014 Elsevier B.V.

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