scholarly journals Equimolar heterodimers in microtubules.

1982 ◽  
Vol 94 (2) ◽  
pp. 263-270 ◽  
Author(s):  
R E Stephens

Two equimolar beta chains can be resolved from sea urchin sperm flagellar and scallop gill ciliary tubulins, and from certain brain tubulins as well, using the Triton X-100-acid-urea polyacrylamide gel system commonly used for histone analysis. The beta chains are identified as such from their mobility on urea-free SDS PAGE, from amino acid composition, and from tryptic peptide distribution. Scallop beta chains have almost identical amino acid profiles but they differ by one tryptic peptide. Optimal conditions for beta chain resolution are very species-dependent, with some closely related species showing either maximal or no beta chain separation. In addition, beef brain tubulin on Triton X-100-acid-urea electrophoresis and scallop gill ciliary tubulin upon isoelectric focusing in the presence of SDS show two approximately equimolar alpha chains. These data, indicating equimolar amounts of two potentially different tubulin heterodimers from a variety of microtubule types, support a model for microtubule structure wherein protofilaments consist of alternating heterodimers of two kinds, generating a 16-nm (2-dimer) axial repeat.

2005 ◽  
Vol 51 (10) ◽  
pp. 875-880 ◽  
Author(s):  
Gou Furusawa ◽  
Takeshi Yoshikawa ◽  
Yoshitaka Takano ◽  
Kazuyuki Mise ◽  
Iwao Furusawa ◽  
...  

The cytoplasmic fibril structures of Saprospira sp. strain SS98-5 grown on a low-nutrient agar medium were purified from cell lysates treated with Triton X-100 and were observed by electron microscopy to be about 7 nm in width and 200–300 nm in length. SDS–PAGE of the fibril structures exhibited a single protein band with a molecular mass of 61 kDa. A Saprospira cytoplasmic fibril protein (SCFP), which is a subunit of the fibril structures, was digested with trypsin to oligopeptides and analyzed for amino acid sequences. A partial nucleotide sequence of the SCFP gene was determined after PCR using primers designated from the amino acid sequences of the oligopeptides. SCFP gene including DNA fragments were detected by Southern hybridization using the PCR product for an SCFP gene as a probe and were cloned to determine whole nucleotide sequences. The SCFP gene indicated relatively higher similarity to conserved hypothetical phage tail sheath proteins. A Western immunoblotting analysis showed that SCFP was significantly expressed in gliding cells as compared with nongliding cells. The above findings with the previously reported results suggest that the cytoplasmic fibril structures are possibly related to the gliding motility of Saprospira sp. strain SS98-5.Key words: Saprospira, gliding motility, Saprospira cytoplasmic fibril protein (SCFP).


1989 ◽  
Vol 61 (03) ◽  
pp. 437-441 ◽  
Author(s):  
Cindra Condra ◽  
Elka Nutt ◽  
Christopher J Petroski ◽  
Ellen Simpson ◽  
P A Friedman ◽  
...  

SummaryThe present work reports the discovery and charactenzation of an anticoagulant protein in the salivary gland of the giant bloodsucking leech, H. ghilianii, which is a specific and potent inhibitor of coagulation factor Xa. The inhibitor, purified to homogeneity, displayed subnanomolar inhibition of bovine factor Xa and had a molecular weight of approximately 15,000 as deduced by denaturing SDS-PAGE. The amino acid sequence of the first 43 residues of the H. ghilianii derived inhibitor displayed a striking homology to antistasin, the recently described subnanomolar inhibitor of factor Xa isolated from the Mexican leech, H. officinalis. Antisera prepared to antistasin cross-reacted with the H. ghilianii protein in Western Blot analysis. These data indicate that the giant Amazonian leech, H. ghilianii, and the smaller Mexican leech, H. officinalrs, have similar proteins which disrupt the normal hemostatic clotting mechanisms in their mammalian host’s blood.


1996 ◽  
Vol 76 (06) ◽  
pp. 0993-0997
Author(s):  
Zhao-Yan Li ◽  
Xiao-Wei Wu ◽  
Tie-Fu Yu ◽  
Eric C-Y Lian

SummaryBy means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)Q(Q/K). It was devoid of phospho-lipaseA, fibrino(geno)lytic, 5′-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell’s viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.


1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).


2021 ◽  
Vol 100 ◽  
pp. 103921
Author(s):  
Diana K. Baigts-Allende ◽  
Alexa Pérez-Alva ◽  
Melissa A. Ramírez-Rodrigues ◽  
Adriana Palacios ◽  
Milena M. Ramírez-Rodrigues

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2033
Author(s):  
Chuleeporn Bungthong ◽  
Sirithon Siriamornpun

Silk proteins have many advantageous components including proteins and pigments. The proteins—sericin and fibroin—have been widely studied for medical applications due to their good physiochemical properties and biological activities. Various strains of cocoon display different compositions such as amino-acid profiles and levels of antioxidant activity. Therefore, the objectives of this study were to find a suitable silk protein extraction method to obtain products with chemical and biological properties suitable as functional foods in two strains of Bombyx mori silk cocoon (Nangsew strains; yellow cocoon) and Samia ricini silk cocoon (Eri strains; white cocoon) extracted by water at 100 °C for 2, 4, 6 and 8 h. The results showed that Nangsew strains extracted for 6 h contained the highest amounts of protein, amino acids, total phenolics (TPC) and total flavonoids (TFC), plus DPPH radical-scavenging activity, ABTS radical scavenging capacity, and ferric reducing antioxidant power (FRAP), anti-glycation, α-amylase and α-glucosidase inhibition. The longer extraction time produced higher concentrations of amino acids, contributing to sweet and umami tastes in both silk strains. It seemed that the bitterness decreased as the extraction time increased, resulting in improvements in the sweetness and umami of silk-protein extracts.


Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1097
Author(s):  
Laura González-Blanco ◽  
Yolanda Diñeiro ◽  
Andrea Díaz-Luis ◽  
Ana Coto-Montes ◽  
Mamen Oliván ◽  
...  

The objective of this work was to demonstrate how the extraction method affects the reliability of biomarker detection and how this detection depends on the biomarker location within the cell compartment. Different extraction methods were used to study the sarcoplasmic and myofibrillar fractions of the Longissimus thoracis et lumborum muscle of young bulls of the Asturiana de los Valles breed in two quality grades, standard (Control) or dark, firm, and dry (DFD) meat. Protein extractability and the expression of some of the main meat quality biomarkers—oxidative status (lipoperoxidation (LPO) and catalase activity (CAT)), proteome (SDS-PAGE electrophoretic pattern), and cell stress protein (Hsp70)—were analyzed. In the sarcoplasmic fraction, buffers containing Triton X-100 showed significantly higher protein extractability, LPO, and higher intensity of high-molecular-weight protein bands, whereas the TES buffer was more sensitive to distinguishing differences in the protein pattern between the Control and DFD meat. In the myofibrillar fraction, samples extracted with the lysis buffer showed significantly higher protein extractability, whereas samples extracted with the non-denaturing buffer showed higher results for LPO, CAT, and Hsp70, and higher-intensity bands in the electrophoretic pattern. These findings highlight the need for the careful selection of the extraction method used to analyze the different biomarkers considering their cellular location to adapt the extractive process.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroki Nishi ◽  
Daisuke Yamanaka ◽  
Masato Masuda ◽  
Yuki Goda ◽  
Koichi Ito ◽  
...  

AbstractStudies on animal models have demonstrated that feeding a low-arginine diet inhibits triacylglycerol (TAG) secretion from the liver, resulting in marked fatty liver development in rats. Here, we first showed that culturing hepatocytes in the medium mimicking the serum amino acid profile of low-arginine diet-fed rats induced TAG accumulation in the cells, indicating that the specific amino acid profile caused TAG accumulation in hepatocytes. Dietary adenine supplementation completely recovered hepatic TAG secretion and abolished hepatic TAG accumulation in rats. A comprehensive non-linear analysis revealed that inhibition of hepatic TAG accumulation by dietary adenine supplementation could be predicted using only serum amino acid concentration data. Comparison of serum amino acid concentrations indicated that histidine, methionine, and branched-chain amino acid (BCAA) concentrations were altered by adenine supplementation. Furthermore, when the serum amino acid profiles of low-arginine diet-fed rats were altered by modifying methionine or BCAA concentrations in their diets, their hepatic TAG accumulation was abolished. Altogether, these results suggest that an increase in methionine and BCAA levels in the serum in response to dietary arginine deficiency is a key causative factor for hepatic TAG accumulation, and dietary adenine supplementation could disrupt this phenomenon by altering serum amino acid profiles.


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