scholarly journals Dephosphorylation of neurofilament proteins enhances their susceptibility to degradation by calpain

1988 ◽  
Vol 256 (2) ◽  
pp. 665-668 ◽  
Author(s):  
H C Pant
Keyword(s):  
Escherichia Coli ◽  
Spinal Cord ◽  
Gel Electrophoresis ◽  
Degradation Rate ◽  
Polyacrylamide Gel Electrophoresis ◽  
High Molecular Mass ◽  
Neurofilament Proteins ◽  
Degradation Rates ◽  
Neurofilament Polypeptides ◽  
Bovine Spinal Cord

The degradation of phosphorylated and dephosphorylated neurofilament proteins by the Ca2+-activated neutral proteinase calpain was studied. Neurofilaments were isolated from bovine spinal cord, dephosphorylated by alkaline phosphatase (from Escherichia coli) and radioiodinated with [125I]-Bolton-Hunter reagent. The radioiodinated neurofilament proteins (untreated and dephosphorylated) were incubated in the presence and absence of calpain from rabbit skeletal muscle, and the degradation rates of large (NF-H), mid-sized (NF-M) and small (NF-L) neurofilament polypeptides were analysed by SDS/polyacrylamide-gel electrophoresis and autoradiography. The degradation of dephosphorylated neurofilament proteins occurred at a higher rate, and to a greater extent, than did that of the phosphorylated (untreated) neurofilament proteins. The dephosphorylated high-molecular-mass neurofilament (NF-HD) was proteolyzed 6 times more quickly than the untreated NF-H. The degradation rate of the NF-M and NF-L neurofilament proteins was also enhanced after dephosphorylation, but less than that of NF-H. This indicates that the dephosphorylation of neurofilament proteins can increase their sensitivity to calpain degradation.

scholarly journals Reductive alkylation of ribosomes as a probe to the topography of ribosomal proteins*

1974 ◽  
Vol 143 (3) ◽  
pp. 607-612 ◽  
Author(s):  
Graham Moore ◽  
Robert R. Crichton
Keyword(s):  
Escherichia Coli ◽  
Protein Complex ◽  
Gel Electrophoresis ◽  
Ribosomal Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Two Dimensional ◽  
Reductive Alkylation ◽  
Lysine Residues

Escherichia coli ribosomes were treated with a number of different aldehydes of various sizes in the presence of NaBH4. After incorporation of either 3H or 14C, the ribosomal proteins were separated by two-dimensional polyacrylamide-gel electrophoresis and the extent of alkylation of the lysine residues in each protein was measured. The same pattern of alkylation was observed with the four reagents used, namely formaldehyde, acetone, benzaldehyde and 3,4,5-trimethoxybenzaldehyde. Every protein in 30S and 50S subunits was modified, although there was considerable variation in the degree of alkylation of individual proteins. A topographical classification of ribosomal proteins is presented, based on the degree of exposure of lysine residues. The data indicate that every protein of the ribosome has at least one lysine residue exposed at or near the surface of the ribonucleo-protein complex.

scholarly journals Purification and characterization of 3-dehydroquinase from Escherichia coli

1986 ◽  
Vol 239 (3) ◽  
pp. 699-704 ◽  
Author(s):  
S Chaudhuri ◽  
J M Lambert ◽  
L A McColl ◽  
J R Coggins
Keyword(s):  
Escherichia Coli ◽  
Gel Electrophoresis ◽  
Catalytic Properties ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Permeation Chromatography ◽  
Purification And Characterization ◽  
Gel Permeation

A procedure has been developed for the purification of 3-dehydroquinase from Escherichia coli. Homogeneous enzyme with specific activity 163 units/mg of protein was obtained in 19% overall yield. The subunit Mr estimated from polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate was 29,000. The native Mr, estimated by gel permeation chromatography on Sephacryl S-200 (superfine) and on TSK G3000SW, was in the range 52,000-58,000, indicating that the enzyme is dimeric. The catalytic properties of the enzyme have been determined and shown to be very similar to those of the biosynthetic 3-dehydroquinase component of the arom multifunctional enzyme of Neurospora crassa.

scholarly journals Studies on the biosynthesis of neurofilament proteins.

1980 ◽  
Vol 85 (3) ◽  
pp. 726-734 ◽  
Author(s):  
H Czosnek ◽  
D Soifer ◽  
H M Wisniewski
Keyword(s):  
Spinal Cord ◽  
Neurofilament Proteins ◽  
Reticulocyte Lysates ◽  
Neurofilament Polypeptides

To determine whether the triplet polypeptides of neurofilaments arise by degradation of precursor, we studied the biosynthesis of neurofilament polypeptides both in vivo and in cell-free systems. Neurofilament-enriched fractions and polyribosomes were prepared from the same rabbit spinal cord homogenates. At 1 h after intracisternal administration of [34S]methionine, radiolabeled neurofilament proteins were detected in spinal cord homogenates as well as in isolated filaments. When polyribosomes from rabbit spinal cord were allowed to incorporate [35S]methionine into protein, triplet polypeptides were among the proteins labeled. Addition of spinal cord polyribosomes to rabbit reticulocyte lysates led to several cycles of translation of the spinal cord mRNA; the three neurofilament polypeptides were among the proteins synthesized in this system. The results demonstrate that the triplet polypeptides of neurofilaments are synthesized as such in the course of individual translational events and do not arise from degradation of P200 or a larger precursor.

scholarly journals Alterations in Protein Expression Caused by thehha Mutation in Escherichia coli: Influence of Growth Medium Osmolarity

1999 ◽  
Vol 181 (10) ◽  
pp. 3018-3024 ◽  
Author(s):  
Carlos Balsalobre ◽  
Jörgen Johansson ◽  
Bernt Eric Uhlin ◽  
Antonio Juárez ◽  
Francisco J. Muñoa
Keyword(s):  
Escherichia Coli ◽  
Growth Medium ◽  
Gel Electrophoresis ◽  
Catabolite Repression ◽  
Protein Pattern ◽  
Polyacrylamide Gel Electrophoresis ◽  
Wild Type ◽  
Phosphotransferase System ◽  
New Family ◽  
Medium Osmolarity

ABSTRACT The Hha protein belongs to a new family of regulators involved in the environmental regulation of virulence factors. The aim of this work was to study the effect of the hha mutation on the overall protein pattern of Escherichia coli cells by two-dimensional polyacrylamide gel electrophoresis. The growth medium osmolarity clearly influenced the effect of the hhamutation. The number of proteins whose expression was altered inhha cells, compared with wild-type cells, was three times larger at a high osmolarity than at a low osmolarity. Among the proteins whose expression was modified by the hha allele, both OmpA and protein IIAGlc of the phosphotransferase system could be identified. As this latter enzyme participates in the regulation of the synthesis of cyclic AMP and hence influences the catabolite repression system, we tested whether the expression of thelacZ gene was also modified in hha mutants. This was the case, suggesting that at least some of the pleiotropic effects of the hha mutation could be caused by its effect on the catabolite repression system.

Cloning, Expression and Characterization of β-Glucosidase from L. Delbrueckii Subsp. Delbrueckii in Escherichia coli

2011 ◽  
Vol 301-303 ◽  
pp. 347-351
Author(s):  
Xiu Hong Zhao ◽  
Jie Zeng ◽  
Hai Yan Gao ◽  
Chang Biao Li ◽  
Chang Jiang Liu
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Prokaryotic Expression ◽  
Expression Vector ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gene Encoding ◽  
Prokaryotic Expression Vector ◽  
Strain Bl21

Gene encoding β-glucosidase was amplified through PCR by using the genome DNA extracted from L .delbrueckii subsp. delbrueckii as a template. The gene encoding β-glucosidase was inserted into a prokaryotic expression vector pET-28a(+) and expressed in E.coli strain BL21(DE3). The gene encoding β-glucosidase was of 1380bp. The nucleotide sequence of the gene encoding β-glucosidase from L. delbrueckii subsp. delbrueckii showed as high as 97.9% homology comparing with that from L. delbrueckii subsp. bulgaricus indicating that the gene encoding β-glucosidase is highly conservative. The enzyme activity was about 34U/mg and the molecular weight of β-glucosidase is about 51 kDa analyzed by SDS-polyacrylamide gel electrophoresis.

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