Eukaryotic initiation factor 4D. Purification from human red blood cells and the sequence of amino acids around its single hypusine residue

Eukaryotic initiation factor 4D (eIF-4D) was purified from human red blood cells by a simple 5-step procedure. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that most of the preparations of eIF-4D were composed of variable amounts of two closely migrating forms of the factor, each of which contained a single residue of the unique amino acid hypusine. The structural similarity of the two forms of human eIF-4D was evidenced by the indistinguishable patterns of radioactivity on peptide maps of tryptic digests prepared from radioiodinated samples. A peptide containing the single hypusine residue was readily isolated from a tryptic digest of human eIF-4D by virtue of its high positive charge and hydrophilic character. Amino acid sequence determination on this peptide revealed the following primary structure around hypusine: Thr-Gly-hypusine-His-Gly-His-Ala-Lys.

Biosynthetic labeling of hypusine in mammalian cells. Carbon-hydrogen bond fissions revealed by dual labeling

Using a dual-label technique in which 3H- and 14C-labeled forms of putrescine and of spermidine were employed as biosynthetic precursors of hypusine, two -C-H bond cleavages were detected during production of this unique amino acid in Chinese hamster ovary cells. One of these cleavages occurs at C-1 of the 4-aminobutyl group during its transfer from the secondary amine nitrogen of spermidine to the nitrogen at the epsilon-position of a specific lysine residue in the polypeptide precursor of eukaryotic initiation factor 4D. Breakage of the other -C-H bond takes place at C-2 in this aminobutyl segment after it has been coupled to lysine to form the intermediate deoxyhypusine residue. Hydroxylation at this carbon atom, which constitutes the last step in hypusine biosynthesis, is the cause of bond cleavage. The data obtained are consistent with a notion that no additional -C-H bond fissions occur during hypusine biosynthesis. Our findings permit suggestion of a mechanism for enzymic aminobutyl group transfer in which 4-aminobutyraldehyde produced by oxidative cleavage of spermidine is coupled with the epsilon-amino group of a specific lysine residue to form an enzyme-bound imine intermediate.

Indirect assays for deoxyhypusine hydroxylase using dual-label ratio changes and oxidative release of radioactivity

Two procedures for rapid assay of deoxyhypusine hydroxylase activity are described. One of these assays measures changes in the 3H:14C ratio of dual-labeled protein that results from the release of tritium from a specific position in the side chain of the 3H,14C-labeled constituent amino acid deoxyhypusine upon its conversion to [3H,14C]hypusine. The other assay relies upon release of radioactivity from product protein by periodate oxidation of the radiolabeled side chain of component hypusine. The good correspondence of each of these assays with the ion exchange chromatographic method which measures hypusine and deoxyhypusine in acid hydrolysates of protein indicates that each provides a valid means of determining deoxyhypusine hydroxylase activity.

Deoxyhypusine hydroxylase from rat testis. Partial purification and characterization

Deoxyhypusine hydroxylase, the enzyme that catalyzes the formation of hypusine from deoxyhypusine in eukaryotic initiation factor 4D, has been partially purified from rat testis. The partially purified enzyme requires only the addition of certain sulfhydryl compounds for catalytic activity, dithiothreitol being the most effective. Its lack of dependency on the alpha-keto acid-dependent dioxygenase cofactors, Fe2+, alpha-ketoglutarate, and ascorbic acid, its failure to decarboxylate stoichiometrically alpha-ketoglutarate with deoxyhypusine hydroxylation, and its strong and specific inhibition by Fe2+ all suggest a catalytic mechanism of this enzyme unlike that of the prolyl and lysyl hydroxylases.

Tubulointerstitial disease in lupus nephritis: relationship to immune deposits, interstitial inflammation, glomerular changes, renal function, and prognosis

The interrelationships between tubulointerstitial immune deposits (TID), interstitial inflammation, glomerular changes, renal function, and prognosis were assessed in the renal biopsies from 93 patients with lupus nephritis. The prevalence of TID was 33% by immunofluorescence and 23% by electron microscopy. Although predominantly detected along and within tubular basement membranes, extraglomerular immune deposits were also present in the wall of renal interstitial capillaries and small arteries as well as in Bowman's capsule. The prevalence of TID correlated with the activity of glomerular lesions and, to a lesser extent, with the severity of proliferative lupus nephritis (WHO classes II-IV). TID were much less common in the membranous form (WHO class V). The severity of interstitial inflammation correlated with the degree of renal insufficiency and was an accurate prognostic indicator of progressive deterioration of renal function. However, there was no correlation between prevalence of TID and prevalence and severity of interstitial inflammation, suggesting that the latter is not necessarily secondary to the presence of immune complexes and that other pathogenetic mechanisms may be involved.

Statistical transformations of indices of gingivitis measured non-invasively

An index (PMGI) that combines the Massler-Schour (PMA) and Löe-Silness (GI) indices for non-invasive scoring of gingivitis was applied in 2 independent comparative clinical studies. 4 statistical transformations of the scores of individual papillary and marginal units were analyzed: the whole-mouth mean, its square root, the proportion of units judged to be inflamed, and its arc sin transformation. According to the criteria of how closely the transformations produced approximately normal distributions, and of how successful they were in detecting treatment differences, the square root transformation performed the best.

The biosynthesis of hypusine (N epsilon-(4-amino-2-hydroxybutyl)lysine). Alignment of the butylamine segment and source of the secondary amino nitrogen

The unusual amino acid hypusine is produced in a single protein of mammalian cells by a novel posttranslational event in which a lysine residue is conjugated with the four-carbon moiety from the polyamine spermidine to form an intermediate deoxyhypusine, and in which this intermediate is subsequently hydroxylated. Specifically isotopically labeled precursors of hypusine were used to identify the biosynthetic origin of some of the atoms of hypusine and thus to provide further insight into the mechanism of this in vivo chemical modification reaction. Radiolabel from [1,4-3H] putrescine, [1,8-3H]spermidine, and [5-3H]spermidine entered hypusine during growth of Chinese hamster ovary cells. The occurrence of this label at positions 1 and 4, at position 4, and at position 1, respectively, in the 4-amino-2-hydroxybutyl portion of hypusine revealed an alignment of atoms identical to that in the butylamine segment of spermidine. Growth of cells with [epsilon-15N]lysine as the source of lysine yielded hypusine enriched in 15N, whereas only isotope-free hypusine during growth by [4-15N]spermidine. These was found in cells whose spermidine was replaced during growth by [4-15N]spermidine. These findings are in accordance with a proposal that the first phase of hypusine biosynthesis, the production of intermediate deoxyhypusine, occurs through transfer of the butylamine moiety from spermidine to the epsilon-amino nitrogen of protein-bound lysine. The technique of thermospray high-performance liquid chromatography/mass spectrometry provided positive identification of 15N in hypusine through final separation and on-column direct analysis of this amino acid. Methods of preparation are given for spermidine of high specific radioactivity, labeled specifically at position 5 with 3H, and for spermidine with 15N at the 4-position.

The mammalian hypusine-containing protein, eukaryotic initiation factor 4D. Structural homology of this protein from several species

A single cellular protein of Mr approximately 18,000 and pI near 5.1, recently identified as eukaryotic translation initiation factor eIF-4D, contains the unusual amino acid hypusine [N epsilon-(4-amino--2-hydroxybutyl)lysine] formed post-translationally from lysine with a structural contribution from the polyamine spermidine. When the 3H-labeled hypusine-containing protein isolated from Chinese hamster ovary (CHO) cells that were grown with radioactive polyamine is digested with trypsin and the digest is subjected to two-dimensional separation, a single radioactive peptide is seen. A labeled peptide that occupies this same position is found in a digest of the [3H]hypusine protein from human lymphocytes and the single hypusine-containing tryptic peptide from purified rabbit reticulocyte eIF-4D also moves to this identical position. Stepwise Edman degradation of the tryptic digest of CHO cell hypusine-protein releases the radioactivity as a single peak in accordance with our earlier evidence for a single hypusine residue per molecule of eIF-4D. The similar patterns of radioactive peptides obtained from tryptic digests of radioiodinated eIF-4D from CHO cells, human lymphocytes, and rabbit reticulocytes suggest a highly conserved primary structure for this protein.

Identification of the hypusine-containing protein hy+ as translation initiation factor eIF-4D

A single protein of Mr 17,000-19,000 and pI approximately equal to 5.1, found in all animal cells we have studied to date, undergoes post-translational modification in growing cells to form the unusual amino acid hypusine. Because of the association of this modification with the increasing rate of protein synthesis during lymphocyte growth stimulation, its subcellular distribution, and its widespread occurrence and structural conservation among animal cells, we considered the possibility that this protein might be a translation initiation factor. Purified rabbit reticulocyte factors (eukaryote initiation factors) eIF-4C and eIF-4D were chosen for study because of their Mr (17,000-19,000) and acidic pI. The hypusine-containing protein and purified eIF-4D showed identity of electrophoretic mobility in both isoelectric focusing and NaDodSO4/polyacrylamide gel electrophoresis dimensions, while eIF-4C was clearly nonidentical. Purified eIF-4D contained approximately 1 mol of hypusine per mol of protein. Since only one protein has thus far been observed to contain hypusine, we conclude that eIF-4D is the hypusine-containing protein. On the basis of relative synthesis among lymphocyte proteins and detection by Coomassie blue staining, we also conclude that eIF-4D is a major cell protein. It is possible that the activity of this factor is modulated by It is possible that the activity of this factor is modulated by post-translational hypusine formation, which may play a role in regulation of protein synthesis during lymphocyte growth stimulation.

Posttranslational formation of hypusine in a single major protein occurs generally in growing cells and is associated with activation of lymphocyte growth

Growing lymphocytes perform a novel chemical modification of a single protein (Hy+: approximately 18 kd, pI approximately 5.1), resulting in the formation of the unusual amino acid, hypusine (N epsilon-[4-amino-2-hydroxybutyl]lysine). This posttranslational event occurs only following activation of lymphocyte growth. Hypusine formation increases at a rate parallel to protein synthesis during the first 24 hr of growth stimulation, beginning before 6 hr of growth. At all times, hypusine is restricted primarily to the single protein, Hy+. In resting cells, the unmodified substrate protein, Hy0, is continuously synthesized and maintained in a steady-state pool of significant size. In several other cell lines, hypusine formation was also observed in a single protein of approximately 18 kd, pI approximately 5.1, indistinguishable electrophoretically from the lymphocyte protein. Thus Hy+ is a ubiquitous protein showing significant conservation among divergent species. Maintenance by resting lymphocytes of a pool of unmodified protein and early activation during growth of the hypusine-forming enzyme system suggest that this posttranslational modification may be of importance to lymphocyte activation.

The biosynthesis of protein-bound hypusine (N epsilon -(4-amino-2-hydroxybutyl)lysine). Lysine as the amino acid precursor and the intermediate role of deoxyhypusine (N epsilon -(4-aminobutyl)lysine)

The major labeled constituent produced in cellular protein during the incubation of Chinese hamster ovary (CHO) cells with [3H]putrescine or [terminal methylenes-3H]spermidine was identified as hypusine (N epsilon -(4-amino-2-hydroxybutyl)lysine). This unusual amino acid was found to occur predominantly in one relatively acidic low molecular weight protein. When CHO cells were labeled with [4,5-3H)lysine, a small portion of the radioactivity of the cellular protein fraction, after release by proteolytic digestion or acid hydrolysis, chromatographed at the position of hypusine. Oxidative degradation of this isolated labeled material yielded labeled lysine, thus, providing evidence that lysine is the amino acid precursor of hypusine. Upon incubation of CHO cells with the metal chelator, alpha,alpha-dipyridyl, and either [4,5]3H]lysine or [terminal methylenes-3H]spermidine, label was incorporated into a protein-bound material, the chromatographic properties of which, after release by digestion, were found to be different from those of hypusine. This constituent of cell protein was identified as the unhydroxylated form of hypusine, deoxyhypusine (N epsilon -(4-aminobutyl)lysine). Evidence that the normal biosynthesis of hypusine proceeds through hydroxylation of deoxyhypusine was obtained by demonstration of conversion of protein-bound deoxyhypusine to protein-bound hypusine both in intact cells and in cell-free lysate. In the presence of the metal chelator, alpha,alpha-dipyridyl, deoxyhypusine accumulated in a single protein whose two dimensional electrophoretic properties were indistinguishable from those of the usual hypusine-containing protein. This finding supports the proposed mechanism in which peptide-bound lysine is converted to peptide-bound hypusine through hydroxylation of the transitory intermediate, deoxyhypusine.

Degradation of ginseng saponins under mild acidic conditions

Ginseng saponins, ginsenosides Rg (1), Re and Rb (1), decomposed under mild acidic conditions to yield prosapogenins. The structures of the prosapogenins were investigated by (13)C-NMR spectroscopy and Rg (1)-prosapogenin II was shown to be a mixture of ginsenoside Rh (1), and its C-20 epimer, produced by hydrolysis followed by epimerization at C-20. Rg (1)-prosapogenin III, the other prosapogenin derived from ginsenoside Rg (1); was a C-25,26 hydrated derivative of Rg (1)-prosapogenin II. Re-prosapogenin II was identified as a mixture of ginsenoside Rg (2) and its C-20 epimer, and Re-prosapogenine III as a C-25,26 hydrated derivative of Re-prosapogenin II.

Identification of hypusine, an unusual amino acid, in a protein from human lymphocytes and of spermidine as its biosynthetic precursor

When normal human peripheral lymphocytes are treated with mitogen and grown in the presence of [3H]putrescine or [terminal methylenes-3H]spermidine, label is incorporated predominantly into one cellular protein. The radioactive constituent of this protein was identified as the unusual amino acid hypusine [N epsilon-(4-amino-2-hydroxybutyl)lysine]. This was accomplished by isolation of the component from proteolytic digests or acid hydrolysates and comparison with authentic hypusine by chromatography, conversion to the 2,4-dinitrophenyl derivative, and oxidative degradation. The observed relationships among intracellular levels of labeled putrescine, polyamines, and protein bound hypusine after growth of cells with the various labeled amines and with or without an inhibitor of polyamine biosynthesis supply evidence that spermidine is the immediate amine precursor of hypusine and that the 4-amino-2-hydroxybutyl portion of hypusine derives from the butylamine moiety of spermidine.

The Carroll rating scale for depression. II. Factor analyses of the feature profiles

Factor analyses were conducted for the Hamilton depression rating scale (HRS) and the self administered Carroll counterpart (CRS). The factor loadings for the respective first factors were similar; those for the respective second factors showed strict sign consistency but only moderate consistency of magnitude; the loadings for the respective third factors showed no particular consistency. The first three CRS and first three HRS factor scores were computed for each individual and correlations were computed from these factor scores. The first and second factors were highly correlated but the third factors were negatively correlated indicating that they were not measuring the same thing. The first factors of the CRS and HRS correlated highly with their respective raw total scores and were indices of the severity of illness. The self-administered CRS (with matching weights) is a credible alternative to the HRS for routine clinical assessment of the severity of depression.

Polyamines as physiological substrates for transglutaminases

When normal human blood lymphocytes are treated with mitogen in the presence of [3H]putrescine, label is incorporated into a few cellular proteins. Labeled N-(gamma-glutamyl) putrescine, N1-(gamma-glutamyl)spermidine, and N8-(gamma-glutamyl)spermidine were identified in exhaustive proteolytic digests of the cellular protein fraction. The enzyme-mediated clotting of rat seminal plasma to which 14C-labeled spermidine and spermine are added is accompanied by incorporation of the polyamines into a number of seminal plasma proteins. Proteolytic digests of the protein fraction from this clotted seminal plasma contain labeled N1-(gamma-glutamyl)spermidine, N8-(gamma-glutamyl)spermidine, N1,N8-bis(gamma-glutamyl)spermidine, N1-(gamma-glutamyl)spermine, and N1,N12-bis(gamma-glutamyl)spermine. These findings support a proposal that polyamines serve as substrates for transglutaminases both in cells and in an extracellular fluid. They show differences in cellular and extracellular substrate properties of the polyamines and indicate cross-linking through these amines in the extracellular system, but provide no evidence for such cross-linking in the cells.

Inter-examiner reliability in caries trials

A statistical model is given for representing the several components of variability present in measurements (e.g., DMFS scores) given by examiners to patients. Methods for making inferences about the intraclass correlation coefficient of reliability are presented and illustrated on a real set of data. The proper analysis of data from a reliability study is shown to depend on the planned design and analysis of the clinical or field trial to be conducted following the reliability trial.

Mutants in three genes affecting transport of magnesium in Escherichia coli: genetics and physiology

Mutants in three genes affecting two Mg2+ transport systems are described. System I, for which Co2+, Mn2+, and Mg2+ are substrates, is inactive in corA mutants corB mutants express system I after growth on high (10 mM) Mg2+ but not low (0.1 mM) Mg2+. Both corA and corB mutants are resistant to Co2+ or Mn2+. corA mutants are sensitive to CA2+. Transport system II is specific for Mg2+ and is repressed by growth on 10 mM Mg2+. mgt mutations inactivate system II. Growth on mgt mutants in normal except on very low (1 muM) concentrations of Mg2+, corA mgt strains exhibit no high-affinity, energy-dependent transport of Mg2+ and require 10 mM Mg2+ for optimal growth. The three genes are not linked. The corA locus is contransducible with ilv at 75 min, corB is cotransducible with pyrB at 85 min, and mgt is cotransducible with malB and mel at 81 min on the genetic map.

Phospholipase activity plays no role in the action of colicin K

1. A mutant lacking both detergent-resistant and detergent-sensitive phospholipase A activities is fully sensitive to colicin K. 2. In the absence of cellular phospholipases A, colicin K does not promote hydrolysis of phosphatidylethanolamine. 3. Cells of the colicin-treated mutant lacking lysophosphatidylethanolamine are as abnormally permeable to Co-2+ as the wind type is. 4. Increased levels of lysophosphatidylethanolamine in colicin-treated cells are not necessary for the increased sensitivity to sodium dodecylsulfate.