scholarly journals Biochemical and immunological analysis of rapidly purified 10-nm filaments from baby hamster kidney (BHK-21) cells.

1978 ◽  
Vol 78 (1) ◽  
pp. 93-109 ◽  
Author(s):  
J M Starger ◽  
W E Brown ◽  
A E Goldman ◽  
R D Goldman

Juxtanuclear birefringent caps (FC) containing 10-nm filaments form during the early stages of baby hamster kidney (BHK-21) cell spreading. FC are isolated from spreading cells after replating by treatment with 0.6 M KCl, 1% Triton X-100 (Rohm & Haas Co., Philadelphia, Pa.) and DNase I in phosphate-buffered saline. Purified FC are birefringent and retain the pattern of distribution of 10-nm filaments that is seen in situ. Up to 90% of the FC protein is resolved as two polypeptides of approximately 54,000 and 55,000 molecular weight on sodium dodecyl sulfate (SDS) polyacrylamide gels. The protein is immunologically and biochemically distinct from tubulin as determined by indirect immunofluorescence, double immunodiffusion, one-dimensional peptide mapping by limited proteolysis in SDS gels, and amino acid analysis. The BHK-21 FC amino acid composition, however, is very similar to that obtained for 10-nm filament protein derived from other sources including brain and smooth muscle. Partial disassembly of 10-nm filaments has been achieved by treatment of FC with 6 mM sodium-potassium phosphate buffer, pH 7.4. The solubilized components assemble into distinct 10-nm filaments upon the addition of 0.171 M sodium chloride.

1976 ◽  
Vol 155 (2) ◽  
pp. 383-389 ◽  
Author(s):  
C Kennedy ◽  
R R. Eady ◽  
E Kondorosi ◽  
D K Rekosh

The molybdenum- and iron-containing protein components of nitrogenase purified from Klebsiella pneumoniae, Azotobacter vinelandii, Azotobacter chroococcum and Rhizobium japonicum bacteroids all gave either one or two protein-staining bands after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, depending on the commercial brand of sodium dodecyl sulphate used. The single band obtained with K. pneumoniae Mo-Fe protein when some commercial brands of sodium dodecyl sulphate were used in the preparation of the electrode buffer was resolved into two bands by the addition of 0.01% (v/v) dodecanol to the buffer. Protein extracted from the two bands obtained after electrophoresis of K. pneumoniae Mo-Fe protein gave unique and distinct peptide ‘maps’ after tryptic digestion. Undissociated Mo-Fe protein contained both sets of tryptic peptides. These data are consistent with Mo-Fe protein from K. pneumoniae being composed of non-identical subunits. Amino acid analyses of the subunit proteins revealed some clear differences in amino acid content, but the two subunits showed close compositional relatedness, with a different index [Metzer, H., Shapiro, M.B., Mosiman, J.E. & Vinton, J.G. (1968) Nature (London) 219, 1166-1168] of 4.7.


1980 ◽  
Vol 85 (2) ◽  
pp. 402-413 ◽  
Author(s):  
N W Chin ◽  
K W Lanks

Proteins involved in the attachment of murine L cells to polystyrene have been identified by a technique designed to iodinate only those macromolecules coming into closet apposition to the substratum. Whereas soluble lactoperoxidase (LPO) catalyzes the radioiodination of a broad spectrum of polypeptides, the same enzyme immobilized on polystyrene tissue culture flasks discriminately labels 55,000 and 42,000 mol wt polypeptides that adhere tightly to the substratum after the cells are removed. One-dimensional peptide mapping following limited proteolysis showed that the labeled 55,000 mol wt polypeptide is similar to a component of comparable molecular weight present in the detergent-extracted cytoskeleton. The functional association of two cytoskeletal structures, presumably 10-nm filaments and actin, is discussed, and alternative explanations for their susceptibility to iodination by immobilized LPO are presented.


1981 ◽  
Vol 88 (1) ◽  
pp. 245-250 ◽  
Author(s):  
S Tsukita ◽  
H Ishikawa ◽  
M Kurokawa

Astroglial filaments approximately 10 nm in diameter were isolated from degenerated mouse optic nerves by Triton X-100 and DNase I treatments followed by sucrose density gradient centrifugation. 2-4 wk after bilateral enucleation, optic nerves contained virtually a single population of 10-nm filaments (astroglial filaments), free from neurofilaments. In negative-staining and thin-section electron microscopy, the isolated filaments were seen as nonbranching linear structures with smooth contour, and were morphologically identical to those in situ. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the isolated filaments to be composed of two major polypeptides with molecular weights of 45,000 and 55,000, present in an approximate molar ratio of 1:1. These findings, together with the results of one-dimensional peptide mapping and solubility study, indicate that the astroglial filaments in the mouse optic nerve are primarily composed of these two polypeptides.


1982 ◽  
Vol 60 (2) ◽  
pp. 108-117 ◽  
Author(s):  
N. C. C. Gray ◽  
K. P. Strickland

A phospholipase A2 acting on phosphatidylinositol (PI) has been purified from the 106 000 × g pellet (microsomal fraction) of bovine grey matter. The purification steps included extraction with Triton X-100 (0.05%), ammonium sulfate fractionation (20–50% fraction), consecutive column chromatographic runs on Sephadex G-200 and DEAE-Sephacel, and preparative gel electrophoresis (on 10.5% polyacrylamide gel). These steps achieved a purification of 1614 times. The purified enzyme ran as a single band on sodium dodecyl sulfate (SDS) gel electrophoresis. Molecular weight estimations gave values of 18 300 by SDS gel electrophoresis and 18 521 based on amino acid analysis. Amino acid analysis showed the presence of 173 residues with aspartic acid (46), glutamic acid (26) and glycine (21) being the most abundant. Single residues of cysteine, tyrosine, and arginine were measured. The remaining 11 amino acids were present in amounts ranging from 3 to 11 residues.The purified enzyme had a pH optimum of 7.4, was heat stable (to 70 °C), and was activated by Ca2+ (5 mM). Other divalent cations were either slightly inhibitory (Mg2+ and Mn2+) or strongly inhibitory (Zn2+). The nonionic detergents, Triton X-100 (0.02 to 0.03%) and octyl glucoside (30 mM) showed 70 and 25% stimulations, respectively. Other detergents showed no effect (Cutscum), slight inhibition (G3634A), or strong inhibition (cetyltrimethylammonium bromide). Determination of the apparent Km and Vmax by an Eisthenal–Cornish-Bowden plot gave values of 0.52 mM and 1440 nmol [1-14C]oleic acid min −1∙mg protein −1, respectively, for 1-acyl-2-[1-,14C]oleoyl-sn glycerol-3-phosphoinositol as substrate. The above plot confirmed the presence of a strong inhibition by substrate (i.e., PI) beyond 0.4 mM. The properties of this enzyme and its location (microsomal) make it uniquely different from other phospholipase A2 activities reported for brain. The microsomal location and preference for PI shown by this enzyme lend support to the view that it may function to form lyso-PI in a deacylation–reacylation cycle for altering the fatty acid distribution in PI.


Blood ◽  
1991 ◽  
Vol 78 (4) ◽  
pp. 1117-1120 ◽  
Author(s):  
D Yannoukakos ◽  
C Vasseur ◽  
C Driancourt ◽  
Y Blouquit ◽  
J Delaunay ◽  
...  

Band 3 variants occur rather frequently in different populations. Based on sodium dodecyl sulfate (SDS)-polyacrylamide electrophoretic properties, a widespread polymorphism (band 3 Memphis) has been previously described. It corresponds to a protein that has been hypothesized to be elongated in its N-terminal cytoplasmic domain. Band 3 from a heterozygote subject for this polymorphism and that displays a normal reactivity towards stilbene disulfonates has been isolated and its primary structure determined by protein chemistry. Reverse-phase high performance liquid chromatography tryptic peptide mapping showed, as the only difference with controls, that the enzymatic cleavage between the two N-terminal peptides did not occur, yielding a 69 residue-long fragment. Further cleavages of this peptide (cyanogen bromide, V8 protease), amino acid composition, and sequence analyses demonstrated that the lysine at position 56 was replaced by a glutamic acid. Thus, surprisingly, a single amino acid change is responsible for the large difference in the electrophoretic behavior. This result suggests that single amino acid substitutions may similarly be involved in the structural modification of several other protein variants, described as elongated or shortened based only on SDS-polyacrylamide electrophoresis studies. When deletions/insertions were confirmed by sequence analysis, their extent was often different from that expected from electrophoresis.


Blood ◽  
2001 ◽  
Vol 98 (6) ◽  
pp. 1662-1666 ◽  
Author(s):  
Kazuo Fujikawa ◽  
Hiroshi Suzuki ◽  
Brad McMullen ◽  
Dominic Chung

Abstract von Willebrand factor (vWF) is synthesized in megakaryocytes and endothelial cells as a very large multimer, but circulates in plasma as a group of multimers ranging from 500 to 10 000 kd. An important mechanism for depolymerization of the large multimers is the limited proteolysis by a vWF-cleaving protease present in plasma. The absence or inactivation of the vWF-cleaving protease results in the accumulation of large multimers, which may cause thrombotic thrombocytopenic purpura. The vWF-cleaving protease was first described as a Ca++-dependent proteinase with an apparent molecular weight of approximately 300 kd. Thus far, however, it has not been isolated and characterized. In this study, the purification of human vWF-cleaving protease from a commercial preparation of factor VIII/vWF concentrate by means of several column chromatographic steps, including 2 steps of heparin-Sepharose column, is reported. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis of the anion exchange and gel filtration column fractions showed that the vWF-cleaving protease activity corresponded to a protein band of 150 kd. After reduction, it migrated with an apparent weight of 190 kd. The amino terminal sequence of the 150-kd band was AAGGIL(H)LE(L)L(D)AXG(P)X(V)XQ (single-letter amino acid codes), with the tentative residues shown in parentheses. A search of the human genome sequence identified the vWF-cleaving protease as a new member of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin type I motif) family of metalloproteinase. An active site sequence of HEIGHSFGLEHE (single-letter amino acid codes) was located at 150 residues from the N terminus of the protein.


1981 ◽  
Vol 89 (3) ◽  
pp. 691-694 ◽  
Author(s):  
K W Lanks ◽  
N W Chin

We have previously shown that lactoperoxidase (LPO) covalently coupled to polystyrene tissue culture flasks can be used to radioiodinate monolayer cell proteins that come into intimate contact with the LPO-polystyrene surface. These studies have now been extended to include a detailed examination of the class of iodinated polypeptides migrating with apparent molecular weights of 50,000 and 55,000 in SDS polyacrylamide gels. Whereas in cultured L929 cells the 55,000 band is predominantly iodinated, in thioglycollate-activated murine peritoneal macrophages the 55,000 and 50,000 bands are of equal intensity. It is possible that the marked degree of exposure of the 50,000 mol wt polypeptide to immobilized LPO is related to the unique strength of macrophages attachment. After labeling of both L929 cells and macrophages with immobilized LPO, all polypeptides in this molecular weight region were subjected to peptide mapping by simultaneous limited proteolysis and electrophoresis in a second SDS polyacrylamide slab gel. The results clearly show that the two major polypeptides in this region are identical within the limits of resolution of this technique. The 55,000 mol wt polypeptide can also be identified in Triton X-100 cytoskeletons from L929 cells after labeling with soluble LPO either before or after detergent lysis. We conclude that this cell surface polypeptide is in continuity with the cytoskeleton and is preferentially exposed to the substratum during attachment to polystyrene.


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