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The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from Neurospora crassa and Saccharomyces cerevisiae. Identification and isolation.

Incubation of mitochondria from Neurospora crassa and Saccharomyces cerevisiae with the radioactive ATPase inhibitor [14C]dicyclohexylcarbodiimide results in the irreversible and rather specific labelling of a low-molecular-weight polypeptide. This dicyclohexylcarbodiimide-binding protein is identical with the smallest subunit (Mr 8000) of the mitochondrial ATPase complex, and it occurs as oligomer, probably as hexamer, in the enzyme protein. The dicyclohexylcarbodiimide-binding protein is extracted from whole mitochondria with neutral chloroform/methanol both in the free and in the inhibitor-modified form. In Neurospora and yeast, this extraction is highly selective and the protein is obtained in homogeneous form when the mitochondria have been prewashed with certain organic solvents. The bound dicyclohexylcarbodiimide label is enriched in the purified protein up to 50-fold compared to whole mitochondria. Based on the amino acid analysis, the dicyclohexylcarbodiimide-binding protein from Neurospora and yeast consists of at least 81 and 76 residues, respectively. The content of hydrophobic residues is extremely high. Histidine and tryptophan are absent. The N-terminal amino acid is tyrosine in Neurospora and formylmethionine in yeast.

Adenosine Triphosphatases

Isolation of a chloroplast N,N'-dicyclohexylcarbodiimide-binding proteolipid, active in proton translocation.

The N,N'-dicyclohexylcarbodiimide-binding proteolipid from lettuce chloroplast membranes has been purified by a novel, rapid technique involving I-butanol extraction and ether precipitation. Reconstitution of this proteolipid into liposomes composed of chloroplast lipids and subsequent incorporation of bacteriorhodopsin resulted in the formation of liposomes exhibiting a light-dependent accumulation of protons. This accumulation was significantly enhanced upon addition of N,N'-dicyclohexylcarbodiimide at concentrations similar to those that inhibit chloroplast adenosinetriphosphatase activity. Radioactively labeled N,N'-dicyclohexylcarbodiimide was found to be incorporated essentially into the proteolipid of the reconstituted liposomes. These results suggest that the functional unit responsible for proton channeling in the chloroplast membrane has been isolated and reconstituted in the native state.

Biological Transport, Active

A mutant ATP synthetase of Escherichia coli with an altered sensitivity to N,N' -dicyclohexylcarbodiimide: characterization in native membranes and reconstituted proteoliposomes.

Dicyclohexylcarbodiimide-resistant mutants of Escherichia coli were isolated and characterized In one mutant the unc genes and affects the membrane-integrated part of the ATP synthetase. The sensitivity of ATP synthetase functions to N,N' -dicyclohexylcarbodiimide was compared in wild-type and mutant membranes. The membrane-integrated part of the wild-type ATP synthetase is highly sensitive to ATP-dependent membrane energization and restoration of lactate-dependent energization of ATPase-depleted membranes. In mutant membranes this concentration has only a slight effect on these activities whereas a severe inhibition is obtained at 200 muM. Using the highly water-soluble 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide theactivities of wild-type and mutant membranes are inhibited to the same extent. TheATP synthetase of wild-type and mutant was partially purified and incorporated muM. Uinto liposomes. These showed an uncoupler-sensitive ATP-32Pi exchange and ATP-dependent quenching of acridine-dye fluorescence. The activities of mutant and wild-type proteoliposomes exhibit the same pattern of sensitivity to dicyclohexylcarbodiimide as the corresponding membranes.

Adenosine Diphosphate

Characterization of the dicyclohexylcarbodiimide-binding protein isolated from chloroplast membranes.

Characterization of a butanol-solubilized protein isolated from chloroplast membranes is reported. The proteolipid, which specifically and covalently binds dicyclohexylcarbodiimide, has an apparent molecular weight of 8,000 in dodecylsulfate electrophoresis. The minimum molecular weight calculated from amino acid analysis data is 7,700. N-Formyl-methionine was determined to be the N-terminal amino acid. Glycine, alanine and leucine were present in elevated amounts, resulting in a polarity of 29%. Cysteine and histidine were lacking. In high-voltage electrophoresis the peptide appeared as a single homogenous spot which migrated, at pH 6.5, with the relative mobility of glycine. At concentrations where dicyclohexylcarbodiimide inhibited ATPase activity maximally (20 nmol per mg membrane protein), 0.17 nmol dicyclohexylcarbodiimide was covalently bound per nmol isolated proteolipid, indicating that one out of six molecules of proteolipid was labeled.

Adenosine Triphosphatases

Purification and reconstitution of the N,N'-dicyclohexylcarbodiimide-sensitive ATPase complex from spinach chloroplasts.

The dicyclohexylcarbodiimide-sensitive ATPase from spinach chloroplast has been isolated. On sodium dodecyl sulfate gels, seven different polypeptides were seen. Five of these polypeptides coincided with the CF1 subunits, a 7,500-dalton peptide was identified as the proteolipid which interacts with [14C]dicyclohexylcarbodiimide, and there was a 15,500-dalton hydrophobic polypeptide with unknown function. In two-dimentional gels, two additional peptides were resolved, one 17,500 daltons (co-migrating in sodium dodecyl sulfate gels with subunit delta) and one 13,500 daltons (co-migrating with subunit epsilon). Reconstitution was obtained by freezing and thawing the complex with a crude mixture of phospholipids. After reconstitution the complex catalyzed 32P1-ATP exchange (rates of 200 to 400 nmoles x mg-1 x min-1) and ATP formation during acid-to-base transition. These reactions were inhibited by dicyclohexylcarbodiimide and uncouplers. Uncouplers at low concentrations stimulated and at high concentrations inhibited the Mg2+-ATPase activity. ATP hydrolysis and 32P1-ATP exchange were catalyzed by the complex in the presence of either Mg2+ or Mn2+ but not with Ca2+ or Co2+. ATP and GTP were substrates for the exchange reaction but not ADP or CTP.

Adenosine Triphosphatases

Purification and properties of a dicyclohexylcarbodiimide-sensitive adenosine triphosphatase from a thermophilic bacterium.

1. A stable ATPase complex with sensitivity to dicyclohexylcarbodiimide (TFo-F1) was purified from the membranes of the thermophilic aerobic bacterium PS3, by ion exchange chromatography in the presence of Triton X-100. 2. The ATPase of TFo-F1 was maximal at 70 degrees at pH 8.6 and was stable after monomerization in 4 M urea and 0.5% Triton X-100 at 25 degrees. The activity was dependent on Mg2+, Co2+, or Mn2+, and it became insensitive to dicyclohexylcarbodiimide when Ca2+ or Cd2+ was added instead. 3. TFo-F1 required P-lipids of this bacterium contained branched fatty acyl groups but no unsaturated groups and were stable against oxidation and heat. 4. Studies by electron microscopy, gel electrophoresis, and use of anti-ATPase antibody and [3H]acetyl-ATPase indicated that the TFo-F1 complex was composed of an ATPase moiety (TF1, five different subunits) and a hydrophobic moiety (TFo, three different subunits. TFo conferred TF1 with sensitivity to dicyclohexylcarbodiimide. 5. Vesicles catalyzing 32Pi-ATP exchange and ATP-driven enhancement of fluorescence of anilinonaphthalene sulfonate were reconstituted by dialyzing pure TFo-F1 and P-lipids together, and were active even at 50-75 degrees. The vesicles reconstituted from TFo-F1 and bacterial P-lipids were more stable than those reconstituted from TFo-F1 and soybean P-lipids.

Adenosine Triphosphatases

The dicyclohexylcarbodiimide-binding protein of rat liver mitochondria as a product of the mitochondrial protein synthesis.

A product of mitochondrial protein synthesis in rat liver mitochondria, characterized by a low molecular weight (Mr is less than 10000) and an unusually high hydrophobicity, has been identified as the dicyclohexylcarbodiimide-binding protein and as a peptide of the hydrophobic sector of the mitochondrial ATPase complex. The purified protein still possesses the ability of bind dicyclohexylcarbodiimide.

Adenosine Triphosphatases

Coupling factor ATPase complex of Rhodospirillum rubrum. Purification and characterization of an oligomycin and N,N'-dicyclohexylcarbodiimide-sensitive (Ca+ + Mg2+)-ATPase.

An ATPase complex sensitive to the energy transfer inhibitors oligomycin, dicyclohexylcarbodiimide and venturicidin has been solubilized from Rhodospirillum rubrum chromatophores with Triton X-100 and further purified by centrifugation on a glycerol gradient. The partially purified RrFo . F1 contains 13 distinct polypeptide subunits, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, including the subunits of the oligomycin-sensitive, water-soluble RrF1 ATPase. The ATPase activity of RrF0 . F1 as that of the membrane-bound enzyme complex depends on Ca2+ or Mg2+ and from detailed kinetic studies it is concluded that the divalent cation-ATP complex is the substrate for both ATPase complexes. Free ATP and free Mg2+ act as competitive inhibitors, with Ki values of 1 mM and 7 muM, respectively. The subunit composition of the purified RrFo . F1 and its similarity to the membrane-bound ATPase with respect to cation dependence and sensitivity to energy transfer inhibitors suggests that it contains all the subunits of the R. rubrum coupling factor-ATPase complex.

Aurovertins

Inhibition of the (Ca2+)ATPase from sarcoplasmic reticulum by dicyclohexylcarbodiimide: evidence for location of the Ca2+ binding site in a hydrophobic region.

Dicyclohexylcarbodiimide (DCCD) inhibits the (Ca2+)ATPase, Ca2+ uptake by sarcoplasmic reticulum vesicles and Ca2+ binding to the (Ca2+)ATPase from sarcoplasmic reticulum. Ca2+ (at micron concentrations) specifically protects against DCCD inhibition. The inhibition can, therefore, be readily demonstrated only in the presence of Ca2+ chelating agents such as EGTA. In the presence of EGTA, the ionophore A-23187 increased the sensitivity to DCCD. The ionophore also increased the phosphorylation of the enzyme by inorganic phosphate in the presence of Mg2+. These results indicate that tightly bound Ca2+ is located in a hydrophobic region of the enzyme which is not accessible to EGTA. Complete inhibition of the (Ca2+)ATPase is accompanied by binding of 4--5 nmol of [14C]DCCD per mg of ATPase protein in the absence of Ca2+ compared with 2 nmol bound per mg in the presence of Ca2+ with no ATPase inhibition. Assuming a molecular weight of 100 000 for the ATPase monomer, about 1 nmol of DCCD inhibits 4 nmol of ATPase. This result suggests that the minimal functional unit of the enzyme is a tetramer. Following trypsin digestion of the [14C]DCCD-labeled ATPase most of the radioactivity appears in the 20 000-dalton fragment. We propose that DCCD reacts with the Ca2+-binding site of the ATPase.

Animals

Adenosine triphosphatase of rat liver mitochondria: detergent solubilization of an oligomycin- and dicyclohexylcarbodiimide-sensitive form of the enzyme.

The hydrolytic activity of the ATPase bound to purified inner membrane vesicles of rat liver mitochondria can be increased threefold by washing extensively with a high ionic strength phosphate buffer. The specific ATPase activities of such phosphate-washed membranes are the highest reported to date for a mitochondrial membrane preparation (21-24 mumol of ATP hydrolyzed min-1 mg-1 in bicarbonate buffer at 37 degrees C). Deoxycholate (0.1 mg/mg of protein) extracts from these membranes a soluble, cold-stable ATPase complex which exhibits a specific activity under optimal assay conditions of 12 mumol of ATP hydrolyzed min-1 mg-1. This complex is not sedimented by centrifugation at 201000 g for 90 min, and readily passes through a 250-A Millipore filter. The ATPase activity of the soluble complex is inhibited 95% by 2.4 muM oligomycin. In addition, inhibitions of 60% or better are obtained in the presence of 1-8 muM dicyclohexylcarbodiimide, p-chloromercuribenzoate, venturicidin, and aurovertin. While a similar complex may be extracted with Triton X-100 this preparation is always lower in both specific activity and in inhibitor sensitivities than the complex extracted with deoxycholate. Detergents of the Tween and Brij series and other detergents of the Triton series are also much less effective than deoxycholate in solubilizing the oligomycin-sensitive. ATPase complex of rat liver. It is concluded that deoxycholate is superior to other detergents as an extractant of the oligomycin-sensitive ATPase complex of rat liver mitochondria, and that the complex extracted with deoxycholate possesses a closer similarity to the membrane-associated ATPase than does the complex extracted with Triton X-100. These studies document the first report of a detergent-solubilized, oligomycin-sensitive ATPase preparation from rat liver mitochondria.

Adenosine Triphosphatases

Restoration of oxidative phosphorylation by purified N,N'-dicyclohexylcarbodiimide-sensitive latent adenosinetriphosphatase from Mycobacterium phlei.

The N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive latent adenosinetriphosphatase (ATPase) (EC 3.6.1.3; ATP phosphohydrolase) from Mycobacterium phlei has been purified to homogeneity and used to resotre oxidative phosphorylation to detergent-extracted membranes. The phosphorylation was inhibited by DCCD any by tetraphenylboron and valinomycin. The enzyme was solubilized from the membrane vesicles by treatment with cholate followed by extraction with Triton X-100. After partial purification on a sucrose gradient, the enzyme was purified to homogeneity by affinity chromatography on Sepharose coupled to ADP. The DCCD-sensitive latent ATPase of coupling factor from M. phlei consists of two components, the latent ATPase (Bcf4), which is insensitive to DCCD, and an intrinsic membrane component, BCF0. This hydrophobic portion of the DCCD-sensitive ATPase was partially purified on a sucrose gradient after solubilization with detergents from membrane vesicles that had been first depleted of the BCF4 by washing with 0.25 M sucrose. When BCF0 was combined with purified BCF4, the latent ATPase of the resulting complex was sensitive to DCCD. Moreover, like the purified DCCD-sensitive latent ATPase, the combined BCF4 and BCF0 restored coupled phosphorylation to detergent-extracted membranes.

Adenosine Triphosphatases

Carbodiimide-binding protein of H+-translocating ATPase and inhibition of H+ conduction by dicyclohexylcarbodiimide.

H+-Translocating ATPase, which catalyzes ATP synthesis in biomembranes, is composed of a head piece (F1) and a membrane moiety (F0). Using highly-purified F0 from a thermophilic bacterium PS3 (TF0), the following results were obtained. 1. Inhibition by N,N'-dicyclohexylcarbodiimide (DCCD) of H+ conduction through TF0 followed pseudo-first-order kinetics. The second-order rate constant for inhibitor-enzyme interaction was 5 times 10(3) M(-1)-min(-1). 2. H+ conductivity blocked by DCCD was proportional to the amount of DCCD incorporated in the band 8 protein of TF0. When only one-third of the band 8 protein was labeled with DCCD, TF0 hardly transported any H+. 3. By extracting TF0 with chloroform-methanol, the band 8 protein was obtained as a proteolipid. Polyacrylamide gel electrophoresis with dodecyl sulfate and urea showed that the molecular weight was about 6,000. 4. The amino acid composition of band 8 protein indicated that this protein contained an extremely high percentage of hydrophobic amino acids (0.29 in polarity) and was devoid of histidine, tryptophan, cysteine, and lysine. Its minimum molecular weight was 6,500. 5. The role of band 8 protein (DCCD-binding protein) in H+ conduction through TF0 is discussed on the basis of these results.

Adenosine Triphosphatases

Preparation of protected peptide hydrazides from the acids and hydrazine by dicyclohexylcarbodiimide-hydroxybenzotriazole coupling.

A mild procedure for preparing protected peptide hydrazides directly from the corresponding carboxylic acids and equivalent amounts of hydrazine, N-hydroxybenzotriazole and dicyclohexylcarbodiimide is described. Side reactions frequently encountered in hydrazinolysis are thus totally avoided. The process is especially useful for the preparation of aspartic acid and glutamic acid containing peptide hydrazides. No racemization of the amino acid residue was observed.

Amino Acid Sequence

Mitochondrial ATPase complex of Aspergillus nidulans and the dicyclohexylcarbodiimide-binding protein.

The dicyclohexylcarbodiimide-binding protein of Aspergillus nidulans has been identified as the smallest subunit of the mitochondrial ATPase complex, and has a molecular weight of approximately 8000. It is extractable from whole mitochondria and from the purified enzyme in neutral chloroform/methanol, contains 30% polar amino acids, and the N-terminal amino acid has been identified as tyrosine. Using a double-labelling technique in the absence and presence of cycloheximide, followed by immunoprecipitation of the enzyme complex with antiserum against Neuospora crassa F1 ATPase, it has been shown that this subunit is synthesized on cytoplasmic ribosomes.

Adenosine Triphosphatases

Identification of the dicyclohexylcarbodiimide-reactive protein component of the adenosine 5'-triphosphate energy-transducing system of Escherichia coli.

Membranes of Escherichia coli contain an adenosine 5'-triphosphate (ATP) energy-transducing system that is inhibited by treatment with dicyclohexylcarbodiimide (DCCD). The carbodiimide-reactive protein component of this system has been identified after treatment with [14C]DCCD. This protein has an apparent molecular weight of 9,000 as judged from acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and is extracted from the membrane with chloroform-methanol (2:1). These properties are similar to the analogous protein previously identified in mitochondria (Cattell et al., 1971). A mutant strain, RF-7, has been isolated which derives energy from oxidative phosphorylation in the presence of 5 mM DCCD. The ATP hydrolase activity of the membraned system in the mutant was considerably less sensitive to inhibition by DCCD than that in the wild type. The carbodiimide-reactive protein, which was easily labeled by [14C]DCCD in the wild type, was labeled much less rapidly in the carbodiimide-resistant mutant. It is thus concluded that the reaction of DCCD with this specific protein leads to inhibition of the ATP energy-transducing reactions. The mutation causing carbodiimide resistance in strain RF-7 was mapped. It is cotransduced with the uncA gene at a frequency exceeding 90%. The mutationally altered protein causing the carbodiimide resistance was not conclusively identified. However, reconstitution experiments indicate that the altered protein is not one of the subunits of the soluble ATP hydrolase activity, which can be removed from the membrane by washing with 1 mM tris(hydroxymethyl)aminomethane buffer lacking Mg2+. The carbodiimide-reactive protein remains with the membrane residue after removal of the soluble ATP hydrolase and is thus distinct from these subunits as well.

Adenosine Triphosphatases

Carbodiimide-resistant mutant of Escherichia coli: suppression of resistance to dicyclohexylcarbodiimide by growth on glucose or glycerol.

We have previously reported on the isolation of a mutant strain of Escherichia coli, RF-7, that has a dicyclohexylcarbodiimide (DCCD)-resistant, membrane-associated adenosine triphosphatase (ATPase) activity (R. H. Fillingame, J. Bacteriol. 124:870--883, 1975). We report here that the DCCD resistance of the ATPase of this mutant varies significantly, depending upon the carbon source used for growth. When strain RF-7 was grown aerobically on either glycerol or glucose or anaerobically on glucose rather than on a combination of succinate, acetate, and malate, ATPase activity was more sensitive to inhibition by DCCD because the carbodiimide-reactive proteolipid reacted more readily with DCCD.

Acetates

[The reaction of pepsin and pepsinogen with dicyclohexylcarbodiimide].

The reaction of pig pepsin and pepsinogen with 3H-dicyclohexylcarbodiimide (DCC-T) is studied. It is found that about three residues of DCC-H incorporate into pepsin molecule and about four residues--into pepsinogen molecule under the excess of carbodiimide. The incorporation of DCC-T into protein results in a deep enzyme and zymogen inactivation: pepsine retains 20% of the proteolytic activity with respect to hemoglobin, and pepsinogen completely loses its potential proteolytic activity. It is found that a part of DCC-T residues attaches to N-terminal part of pepsinogen, which splits off under the activation of proenzyme in acid medium. It is demonstrated that the interaction of DCC-T with carboxyl groups of dicarbonic amino acids results in the change of isoelectric point of pepsin and pepsinogen.

Animals