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1.
A porin activity of purified lambda-receptor protein from Escherichia coli in reconstituted vesicle membranes. 总被引:2,自引:0,他引:2
T Nakae 《Biochemical and biophysical research communications》1979,88(3):774-781
The receptor protein for bacteriophage λ was purified to homogeneity from a mutant strain of K-12 producing reduced amounts of porin. In the reconstituted vesicle membranes the λ-receptor formed permeability channels that allowed the diffusion of maltose, lactose, sucrose, raffinose, amino acids, and nucleosides, but essentially not of stachyose. The permeability channels made of λ-receptor thus had a relatively low specificity for solute molecules. The active form of the protein seemed to be an oligomer of λ-receptor proteins. 相似文献
2.
Hiroshi Nikaido Sun Ah Song Leora Shaltiel Marjatta Nurminen 《Biochemical and biophysical research communications》1977,76(2):324-330
Rates of diffusion of a β-lactam antibiotic, cephaloridine, across the outer membrane of cells were measured by determining the rates of its hydrolysis by β-lactamases located in the periplasmic space. It was shown that the permeability coefficient of the outer membrane toward cephaloridine decreased to about one-tenth of that in the wild type, in mutant strains deficient in two “porin” proteins, previously shown to produce transmembrane pores in in vitro reconstitution experiments. In contrast, the loss of the 33,000 dalton outer membrane protein did not have any noticeable effect on the permeability coefficient. 相似文献
3.
A cytochrome - cytochrome oxidase complex containing 0.8–1.0 moles of cytochrome per mole of cytochrome oxidase (heme a + a3) was isolated as described by Ferguson-Miller, S., Brautigan, D.L., and Margoliash E., J. Biol. Chem. , 1104 (1976). This complex was reacted with dithiobissuccinimidyl propionate, an 11 Å bridging bifunctional reagent, and the cross-linked products obtained were analyzed by two dimensional gel electrophoresis. Cytochrome was cross-linked to subunit II of cytochrome oxidase. Other cross-linked products were formed involving different subunits of cytochrome oxidase. These included I+V, II+V, III+V, V+VII, IV+VI and IV+VII. Experiments are also described using N,N′-bis(3-succinimidyloxycarbonylpropyl) tartarate. The major product formed with this 18 Å bridging bifunctional reagent was a pair containing II+VI. 相似文献
4.
R L Melnick L G Monti S M Motzkin 《Biochemical and biophysical research communications》1976,69(1):68-73
The mechanism of integration of λll, which is deleted of all the known λ recombination genes, was studied using deleted hosts as recipients. The presence of BC DNase and I in the recipient cells affected the fate of λll DNA. In nine of ten transductants, insertion of the λll genome took place somewhere between J and N and the remaining one had abnormally permuted prophage λ. In this lysogen (#42), the sequence of prophage genes was similar to that of vegetative phage λ. The properties of lysogen #42 were compared with those of other lysogens. 相似文献
5.
M A McIntosh C L Pickett S S Chenault C F Earhart 《Biochemical and biophysical research communications》1978,81(4):1106-1112
A novel iron uptake system was observed in pseudorevertants of , strains defective in ferrienterochelin transport. The new system is unique in that it is an active transport system that does not utilize any known siderophore. Acquisition of the new uptake system occurs concomitantly with the loss of two major outer membrane proteins (b and c) believed to function as structural components of transmembrane pores. 相似文献
6.
H Kung M Tainsky H Weissbach 《Biochemical and biophysical research communications》1978,81(3):1000-1010
The regulation of the synthesis of the N-terminal portion of the β-galactosidase molecule (α-peptide) has been investigated using DNA fragments of the lactose operon as template. DNA fragments of about 789 base pairs were isolated after endonuclease (Hin II) digestion of either λplac5, λh80dlacps or λh80dlacUV5 phage DNA or DNA from the recombinant plasmid PMC3. The regulation of the expression of these fragments is similar to that observed for the synthesis of β-galactosidase using total phage or plasmid DNA as template, indicating that the regulatory regions on the fragments are intact and functional. Thus, the synthesis of the α-peptide required an inducer due to the presence of repressor in the S-30 extract used. In addition a dependency on adenosine 3′,5′-cyclic monophosphate (cAMP)1 for α-peptide synthesis was obtained with the fragments isolated from λplac5 and λh80dlacps DNAs, whereas little effect of cAMP was seen with the fragment isolated from λh80dlacUV5 phage DNA or PMC3 plasmid DNA containing a UV5 promotor region. However, a significant difference in the effect of guanosine-3′-diphosphate-5′-diphosphate (ppGpp) was observed. With the total phage DNA as template, ppGpp resulted in a 2–4 fold stimulation whereas with the fragment, or PMC3 plasmid DNA, directed synthesis of the α-peptide no significant stimulation by ppGpp was seen. 相似文献
7.
Brian R. Booth 《Biochemical and biophysical research communications》1980,94(4):1029-1036
Cell surface proteins of K12 have been labelled with 125I using a lactoperoxidase method. Results suggest that most outer membrane proteins so far characterised appear to have at least part of their polypeptide chain on the cell surface. These include major outer membrane protains I and II1, the maltose and vitamin B12 binding proteins and proteins involved in iron transport. The labelling of an antibiotic sensitive mutant and its parent were compared but their labelling patterns did not appear to differ in any way which would suggest the cause of the permeability difference between these two strains. 相似文献
8.
The stimulation of protein synthesis by NAD+ in rabbit reticulocyte lysates has been reported. [Lennon M. B., Wu, J., and Suhadolnik, R. J., (1976) Biochem. Biophys. Res. Commun. 72, 530–538]. NAD+ can replace the creatine phosphate-creatine phosphokinase () energy regenerating system normally used in in vitro protein synthesizing systems. The replacement of by NAD+ is optimal at 37 °C. A significant lag in the rate of protein synthesis with NAD+ is observed with decreasing temperatures. Analysis of the adenylate energy charge with NAD+ shows an initial rapid decrease. This decrease in the energy charge recovers with increasing NAD+ concentrations. The energy level correlates with the rates of incorporation of d,l-[4,5-3H(N)]leucine into protein. ATP production via NAD+ pyrophosphorylase or oxidative phosphorylation does not explain the stimulation by NAD+. Rather, the stimulation is correlated with the activation of glycolysis. Glycolysis is not active in lysate preparations because NAD+ is absent. Additional possible roles of NAD+ in protein synthesis are discussed. 相似文献
9.
S F Jackson B R Wentzell D R McCalla K B Freeman 《Biochemical and biophysical research communications》1977,78(1):151-157
L(+)--chloramphenicol induces reversion of His? strains TA100 and TA1535 in the conventional Ames' assay without microsomal activation. Any mutagenicity of D(?)--chloramphenicol was masked by toxicity. Similarly, a sensitive fluctuation test showed mutagenesis with L(+)--chloramphenicol at concentrations of 0.5 μM and above but the D(?) isomer proved to be toxic even at these low levels. The L(+) isomer caused single strand breaks in the DNA of and strains TA1535, TA100 and TA1976. The D(?) isomer caused breaks in and TA1976 although it was less effective and it did not produce DNA breaks in TA1535 or TA100. 相似文献
10.
E L Kline V Bankaitis C S Brown D Montefiori 《Biochemical and biophysical research communications》1979,87(2):566-574
The ability of imidazole acetic acid (IA) to substitute for cAMP was demonstrated by use of a series of strains carrying a lesion in the structural gene. The substitution of IA for cAMP was specific for the L-arabinose operon in that this compound was ineffective in substituting for cAMP in the lactose or maltose catabolic systems. The cAMP receptor protein (CRP) and the gene product were necessary for the IA mediated induction of the L-arabinose system. 相似文献
11.
Oxidation of erythrocyte membrane SH-groups by diamide and tetrathionate induces cross-linking of spectrin (Haest, C.W.M., Kamp, D., Plasa, G. and Deuticke, B. (1977) Biochim. Biophys. Acta 469, 226–230). This cross-linking was now shown to go along with a concentration- and time-dependent enhancement of membrane permeability for hydrophilic nonelectrolytes and ions. The enhancement is specific for oxidative SH-group modifications, is reversible by reduction of the induced disulfides, can be suppressed by a very brief pre-treatment of the cells with low concentrations of and is strongly temperature-dependent. The pathway of the induced permeability discriminates nonelectrolytes on the basis of molecular size and exhibits a very low activation energy (). These findings are reconcilable with the formation of a somewhat inhomogeneous population of aqueous pores with radii probably . Estimated pore numbers vary with the size of the probe molecule. Assuming a diffusion coefficient as in bulk water within the pore, at least 20 pores per cell have to be postulated; more realistic lower diffusion coefficients increase that number. Alterations of the lipid domain by changes of cholesterol contents and insertion of hexanol or nonionic detergents alter the number or size of the pores. Since aggregation of skeletal and intrinsic membrane proteins also occurs after the SH-oxidation, in parallel to the formation of membrane leaks, one may consider (a) defects in the disturbed bilayer interface, (b) a mismatch between lipid and intrinsic proteins or (c) channels inbetween aggregated intrinsic proteins as structures forming the pores induced by diamide treatment. 相似文献
12.
Identification of an Escherichia coli inner membrane polypeptide specified by a lambda-tonB transducing. 总被引:1,自引:0,他引:1
Analysis by polyacrylamide gel electrophoresis of the proteins coded by a λB transducing phage, after infection of UV-irradiated bacteria, revealed the presence of at least 7 new polypeptides. Three of these were identified as proteins of the operon whilst three others were deleted by a spontaneous mutation in the B region carried by the phage. A single polypeptide, molecular weight 40,000 was absent from a phage carrying a proflavine induced mutation in B. We conclude that this protein, which was localised in the inner membrane by sarkosyl fractionation of the envelope, is the product. 相似文献
13.
Functionally inverted plasma membrane vesieles isolated from the eukaryotic microorganism Neurospora crassa generate and maintain a transmembrane electrical potential via ATP hydrolysis catalyzed by a plasma membrane ATPase (G. A. Scarborough, 1976, Proc. Nat. Acad. Sci. USA73, 1485–1488). In order to facilitate investigation of the molecular mechanism of the electrogenic ATPase, and other transport systems, we have developed a method for the large scale isolation and storage of Neurospora plasma membranes in a stable form. Large quantities of open plasma membrane sheets (ghosts) are isolated by a scaled-up modification of the original method (G. A. Scarborough, 1975, J. Biol. Chem.250, 1106–1111) and stored at ?26°C in 60% glycerol (). As needed, the ghosts are washed free of glycerol and then converted to closed vesicles by a modification of the original method. With this technique, plasma membrane vesicles with normal electrogenic pump activity can be prepared daily in approximately 2.5 h. 相似文献
14.
The possible structural relationships among four high molecular weight mechanochemical proteins has been examined using two-dimensional mapping of the tryptic peptide fragments prepared from 125I-labeled proteins (Elder et al., J. Biol. Chem. :6510–6515 (1977)). Erythrocyte spectrin bands 1 and 2 protein, the heavy chain of smooth muscle (uterine) myosin, a filamin from human and rabbit were studied. The maps of the four proteins within each species differed considerably from each other, with no apparent homologies evident among them, whereas maps of the same individual protein between the two species showed a high degree of homology. 相似文献
15.
Phosphorylation of calf thymus H1 histone by calcium-activated,phospholipid-dependent protein kinase
Yasushi Iwasa Yoshimi Takai Ushio Kikkawa Yasutomi Nishizuka 《Biochemical and biophysical research communications》1980,96(1):180-187
Ca2+-activated, phospholipid-dependent protein kinase recently found in mammalian tissues (Takai, Y., Kishimoto, A., Iwasa, Y., Kawahara, Y., Mori, T., and Nishizuka, Y. (1979) , 3692–3695) is able to phosphorylate five fractions of calf thymus histone. H1 histone serves as a preferential substrate, and approximately two moles of phosphate are incorporated into every mole of this histone. Analysis on the N-bromosuccinimide-bisected fragments of this radioactive histone has revealed that the enzyme phosphorylates preferentially seryl and threonyl residues located in the carboxyl-terminal half of this histone molecule. 相似文献
16.
Gilbert Richarme 《Biochemical and biophysical research communications》1982,105(2):476-481
The periplasmic galactose binding protein and maltose binding protein of are recovered mostly in dimeric form when purified, from osmotically-shocked bacteria, in the presence of protease inhibitors and 2-mercaptoethanol without dialysis and concentration of the shock fluid. The specific ligands, galactose (but not glucose) for galactose binding protein, and maltose for maltose binding protein, provoque the monomerisation of the dimeric native forms. These results are discussed in relation to the function of both binding proteins in transport and chemotaxis. 相似文献
17.
Recently, it was suggested that the measured rate of reduction of ferricyto chrome by O?2 below pH 8, was too high in the presence of high concentrations of formate (Koppenol, W.H., Van Buuren, K.J.H., Butler J. and Braams, R. (1976) Biochim. Biophys. Acta 449, 157–168).The high values were attributed to the presence of impurities of copper, which compete for O?2. This assumption is consistent with either a decrease in the reduction yield of ferricytochrome in the presence of copper, or with a very fast reaction of Cu(I) with ferricytochrome .It was previously shown by us and by others that the reduction yield of ferricytochrome by O?2 is 100%. We measured the rate of reduction of ferricytochrome by Cu(I), and found that this reaction is slow: .Therefore, our results rule out the possibility that below pH 8 copper impurities affect the measured rate constant of the reduction of ferricytochrome by O?2. 相似文献
18.
Jørgen Vinten 《生物化学与生物物理学报:生物膜》1978,511(2):259-273
The transport of in white fat cells was measured under equilibrium exchange conditions at concentrations up to 50 mM with a previously described method (Vinten, J., Gliemann, J. and Østerlind, K. (1976) J. Biol. Chem. 251, 794–800). Under these conditions the main part of the transport was inhibitable by cytochalasin B. The inhibition was found to be of competitive type with an inhibition constant of about 2.5 · 10?7 M, both in the absence and in the presence of insulin (1μM). The cytochalasin B-insensitive part of the permeability was about 2 · 10?9 cm · s?1, and was not affected by insulin. As calculated from the maximum transport capacity, the half saturation constant and the volume/ surface ratio, the maximum permeability of the fat cell membrane to at 37°C and in the presence of insulin was 4.3 · 10?6 cm · s?1. From the temperature dependence of the maximum transport capacity in the interval 18–37°C and in the presence of insulin, an Arrhenius activation energy of was found. The corresponding value was in the absence of insulin. The half saturating concentration of was about 6 mM in the temperature interval used, and it was not affected by insulin, although this hormone increased the maximum transport capacity about ten-fold to 1.7 mmol · s?1 per 1 intracellular water at 37°C. 相似文献
19.
B Lipińska A Podhajska K Taylor 《Biochemical and biophysical research communications》1980,92(1):120-126
The coliphage λ DNA replication proteins, the - and -gene products, have been identified by infection of nonpermissive minicells with the appropriate λ amber mutants as proteins of a molecular weight of about 34000 and 23000, respectively. Proteins of exactly the same size were found in minicells harbouring the plasmid . Both proteins seem to be synthesized at the same rate. In λ-infected minicells, as well as in -harbouring minicells the pulse-and-chase experiments have shown an exceptionally rapid decay of the O-protein. 相似文献
20.
The replication defective transducing phage λp3 carries a portion of the operon in the 2 region of the lambda phage. This operon segment contains the promoter, the operator, and the β-galactosidase gene, but does not contain the repressor gene. The gene can be expressed from both the inserted promoter and the phage promoter. When strain 594 (?, +) or JC6256 (Δ) is infected by λp3 in the absence of additional cyclic AMP, β-galactosidase synthesis is shown to be expressed from the phage promoter. When 594 (λ+) or JC6256 (λ+) is infected by λp3 in the presence of additional cyclic AMP and IPTG, β-galactosidase synthesis is shown to be expressed from the inserted promoter.The ability to separate the phage promoter from the inserted promoter for β-galactosidase expression will simplify the interpretation whenever λp5 is used. 相似文献