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1.
Highly purified histone H2B from rat chloroleukaemia has been isolated by preparative electrophoresis at pH 2.7 in polyacrylamide slab gel, using the fraction F2b of Johns (Johns E. W. (1964) Biochem, J. 92, 55-59) as starting material. This histone was characterized by amino acid analysis and end groups determination. Comparative studies with homologous calf thymus histone show similarity of the amino acid compositions and of the amino terminal groups. the carboxyl terminal sequence presents two conservative substitutions. 相似文献
2.
G. Cecilia Toro Christer Wernstedt Carlos Medina Nicols Jaramillo Ulf Hellman Norbel Galanti 《Journal of cellular biochemistry》1992,49(3):266-271
Trypanosoma cruzi presents six histones electrophoretically resolved in three gel systems. Indirect evidence shows that one of these histones, name, corresponds to H4 in other species. We present evidence that histones is H4 by sequencing its amino terminal end. The amino terminal of T. cruzi histone H4, unlike that of other H4s examined thus far is not blocked. Moreover, this protein presents two variants. This partial amino acid sequence of T. cruzi histone H4 differs greatly from homologous sequences of human, yeast, or Tetrahymena. Since the conservatism of the core histones (H2A, H2B, H3, and H4) is clearly illustrated by comparative sequence analyses, the data shown here demonstrates that T. cruzi histone H4 is the most divergent reported. Quantitative analysis of the data suggests that the rate of substitutions in the histone H4 amino terminal sequence varies among different lineages. We postulate a slow-down in the evolutionary rate of histone H4 amino terminal domain in the metazoa branch related perhaps to the appearance of a novel function for this domain. 相似文献
3.
《The International journal of biochemistry》1980,11(3):465-469
- 1.1. Highly purified histone H2B from ox pancreas has been isolated by preparative electrophoresis in polyacrylamide slab gel, at pH 2.7 using the fraction F2b as starting material.
- 2.2. This histone was characterized by amino acid analysis, end groups determination and the tryptic peptide maps.
- 3.3. Comparative studies of histone H2B from ox pancreas and homologous calf thymus histone show similarity of the amino acid compositions, amino terminal groups as well as the tryptic peptide maps.
4.
R.Edward Branson Sidney R. Grimes Gene Yonuschot J.Logan Irvin 《Archives of biochemistry and biophysics》1975,168(2):403-412
Polyacrylamide gel electrophoresis of the histones of the nuclei of seminiferous epithelial cells of rat testis revealed the five principal histone fractions which are found in liver and other somatic tissues, but, in addition, three unusual bands (desginated X1, X2, and X3) were observed. Fraction X1 had a mobility slightly less than that of F1 and was isolated with F1 in the fractionation procedure of Johns. F1 and X1 were separated by chromatography on carboxymethylcellulose, and they were shown by amino acid analyses to be closely related lysine-rich histones. However, X1 had lower content of lysine and alanine and higher content of arginine, aspartic acid, serine, proline, valine and leucine than F1. Both of these fractions had blocked amino-terminal residues, and both had a lysine residue at the carboxyl terminus. These fractions had similar molecular weights by electrophoresis on sodium dodecyl sulfate gels.Fraction X2 migrated between histone fractions F1 and F3 on electrophoresis while X3 migrated between fractions F2b and F3. Fraction X3 was isolated with F2b during fractionation by the Johns procedure. Fraction X2 has received minimal study, and this fraction may not be unique to the testis inasmuch as a faint band in approximately the position of X2 can be seen in electrophoretic patterns of rat liver histones.The results of the treatment of the histone fractions with alkaline phosphatase indicated that the electrophoretic differences between X1 and F1, or X3 and F2b are not attributable to phosphorylation. 相似文献
5.
G. Cecilia Toro Norbel Galanti Ulf Hellman Christer Wernstedt 《Journal of cellular biochemistry》1993,52(4):431-439
The existence of histone H1 has been questioned in Trypanosomatids. We report here the presence of a histone H1 in the chromatin of Trypanosoma cruzi. This protein was purified by narrow-bore reversed phase HPLC and its amino acid composition analyzed and compared with histones H1 from other species. Furthermore, the purified chromosomal protein was digested with proteases and the amino acid sequences of the resulting peptides were analyzed by the automated Edman degradation. The sequences obtained were found to present a high degree of homology when compared to the carboxy terminal domain of other known histones H1. 相似文献
6.
Seebach D Lukaszuk A Patora-Komisarska K Podwysocka D Gardiner J Ebert MO Reubi JC Cescato R Waser B Gmeiner P Hübner H Rougeot C 《化学与生物多样性》2011,8(5):711-739
The terminal homologation by CH2 insertion into the peptides mentioned in the title is described. This involves replacement of the N‐terminal amino acid residue by a β2‐ and of the C‐terminal amino acid residue by a β3‐homo‐amino acid moiety (β2hXaa and β3hXaa, resp.; Fig. 1). In this way, the structure of the peptide chain from the N‐terminal to the C‐terminal stereogenic center is identical, and the modified peptide is protected against cleavage by exopeptidases (Figs. 2 and 3). Neurotensin (NT; 1 ) and its C‐terminal fragment NT(8–13) are ligands of the G‐protein‐coupled receptors (GPCR) NT1, NT2, NT3, and NT analogs are promising tools to be used in cancer diagnostics and therapy. The affinities of homologated NT analogs, 2b – 2e , for NT1 and NT2 receptors were determined by using cell homogenates and tumor tissues (Table 1); in the latter experiments, the affinities for the NT1 receptor are more or less the same as those of NT (0.5–1.3 vs. 0.6 nM ). At the same time, one of the homologated NT analogs, 2c , survives in human plasma for 7 days at 37° (Fig. 6). An NMR analysis of NT(8–13) (Tables 2 and 4, and Fig. 8) reveals that this N‐terminal NT fragment folds to a turn in CD3OH. – In the case of the human analgesic opiorphin ( 3a ), a pentapeptide, and of the HIV‐derived B27‐KK10 ( 4a ), a decapeptide, terminal homologation (→ 3b and 4b , resp.) led to a 7‐ and 70‐fold half‐life increase in plasma (Fig. 9). With N‐terminally homologated NPY, 5c , we were not able to determine serum stability; the peptide consisting of 36 amino acid residues is subject to cleavage by endopetidases. Three of the homologated compounds, 2b, 2c , and 5c , were shown to be agonists (Fig. 7 and 11). A comparison of terminal homologation with other stability‐increasing terminal modifications of peptides is performed (Fig. 5), and possible applications of the neurotensin analogs, described herein, are discussed. 相似文献
7.
Bhargava Kalpana Rao R. Balaji 《International journal of peptide research and therapeutics》2001,8(1):41-45
Summary We studied the effect of incorporating a chiral terminal amino acid residue (L-leucine) on the helical screw sense of a previously
characterized achiral helical polypeptide module-[glycine-(Cα,α-di-n-butylglycine)-glycine]2-by means of CD spectroscopy and conclude that the presence of this residue at the carboxyl terminal induces a predominantly
left handed helical conformation of the helix. 相似文献
8.
S H Quarfordt R S Jain L Jakoi S Robinson F Shelburne 《Biochemical and biophysical research communications》1978,83(3):786-793
Ubiquitin was first found in nuclei in protein A24 where its carboxyl terminal is covalently bound to histone 2A by an isopeptide linkage (Goldknopf, I. L. and Busch, H. (1977) Proc. Natl. Acad. Sci. USA , 864–868). Two-dimensional polyacrylamide gel electrophoresis of the 0.4 N H2SO4 soluble proteins from fractionated rat liver chromatin showed that protein A24 and histones H1, H2A, H2B, H3 and H4 were present in fractions P1 and P2 and markedly diminished in relative amounts in fraction S2. Conversely, a spot designated Ub was found in fraction S2 along with an increased amount and number of non-histone proteins. The Ub spot was not found in chromatin fractions P1 and P2. Ub was identified as ubiquitin by migration on two-dimensional gels and after purification by preparative polyacrylamide gel electrophoresis by its methionine NH2-terminal amino acid and its amino acid composition. 相似文献
9.
PARTICIPATION OF Y89 AND Y97 IN THE CONJUGATING ACTIVITY OF Drosophila melanogaster GLUTATHIONE S‐TRANSFERASE D3 (DmGSTD3)
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Kithalakshmi Vignesvaran Zazali Alias 《Archives of insect biochemistry and physiology》2016,92(3):210-221
Drosophila melanogaster glutathione S‐transferase D3 (DmGSTD3) has a shorter amino acid sequence as compared to other GSTs known in the fruit flies. This is due to the 15 amino acid N‐terminal truncation in which normally active amino acid residue is located. The work has made use of homology modeling to visualize the arrangement of amino acid side chains in the glutathione (GSH) substrate cavity. The identified amino acids were then replaced with amino acids without functional groups in the side chains and the mutants were analyzed kinetically. Homology modeling revealed that the side chains of Y89 and Y97 were shown facing toward the substrate cavity proposing their possible role in catalyzing the conjugation. Y97A and Y89A GSH gave large changes in Km (twofold increase), Vmax (fivefold reduction), and Kcat/Km values for GSH suggesting their significant role in the conjugation reaction. The replacement at either positions has not affected the affinity of the enzyme toward 1‐chloro‐2,4‐dinitrobenzene as no significant change in values of Kmax was observed. The replacement, however, had significantly reduced the catalytic efficiency of both mutants with (Kcat/Km)GSH and (Kcat/Km)CDNB of eight‐ and twofold reduction. The recombinant DmGSTD3 has shown no activity toward 1,2‐dichloro‐4‐nitrobenzene, 2,4‐hexadienal, 2,4‐heptadienal, p‐nitrobenzyl chloride, ethacrynic acid, and sulfobromophthalein. Therefore, it was evident that DmGSTD3 has made use of distal amino acids Y97 and Y89 for GSH conjugation. 相似文献
10.
Yosuke Demizu Masakazu Tanaka Mitsunobu Doi Masaaki Kurihara Haruhiro Okuda Hiroshi Suemune 《Journal of peptide science》2010,16(11):621-626
A single chiral cyclic α,α‐disubstituted amino acid, (3S,4S)‐1‐amino‐(3,4‐dimethoxy)cyclopentanecarboxylic acid [(S,S)‐Ac5cdOM], was placed at the N‐terminal or C‐terminal positions of achiral α‐aminoisobutyric acid (Aib) peptide segments. The IR and 1H NMR spectra indicated that the dominant conformations of two peptides Cbz‐[(S,S)‐Ac5cdOM]‐(Aib)4‐OEt ( 1) and Cbz‐(Aib)4‐[(S,S)‐Ac5cdOM]‐OMe (2) in solution were helical structures. X‐ray crystallographic analysis of 1 and 2 revealed that a left‐handed (M) 310‐helical structure was present in 1 and that a right‐handed (P) 310‐helical structure was present in 2 in their crystalline states. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
11.
E Hashimoto M Takeda Y Nishizuka 《Biochemical and biophysical research communications》1975,66(2):547-555
Calf thymus histone H2B was 32P-labelled by incubation with [γ32P]ATP and adenosine 3′,5′-monophosphate-dependent protein kinase from silkworm pupae. Three major radioactive tryptic phosphopeptides were isolated by a series of column chromatographies and analyzed for their amino acid compositions. Comparison of the data with the known primary structure of the histone revealed their amino acid sequences as Lys-Glu-Ser-Tyr-Ser-Val-Tyr-Val-Tyr-Lys, Lys-Arg-Ser-Arg and Ser-Arg. Chymotryptic digestion of the first tryptic phosphopeptide produced quantitatively radioactive Lys-Glu-Ser-Tyr. Eighty five per cent of the initial acid-precipitable phosphate was recovered at Ser-32 (32%) and Ser-36 (53%). 相似文献
12.
Takumi Kawasaki 《Biochemical and biophysical research communications》2009,385(1):49-54
Store-operated Ca2+ entry (SOCE) is a universal mechanism to increase intracellular Ca2+ concentrations in non-excitable cells. It is initiated by the depletion of ER Ca2+ stores, activation of stromal interaction molecule (STIM) 1 and gating of the Ca2+ release activated Ca2+ (CRAC) channel ORAI1 in the plasma membrane. We identified a minimal activation domain in the cytoplasmic region of STIM1 (CCb9) which activated Ca2+ influx and CRAC currents (ICRAC) in the absence of store depletion similar to but more potently than the entire C terminus of STIM1. A STIM1 fragment (CCb7) that is longer by 31 amino acids than CCb9 at its C terminal end showed reduced ability to constitutively activate ICRAC consistent with our observation that CCb9 but not CCb7 efficiently colocalized with and bound to ORAI1. Intracellular application of a 31 amino acid peptide contained in CCb7 but not CCb9 inhibited constitutive and store-dependent CRAC channel activation. In summary, these findings suggest that CCb9 represents a minimal ORAI1 activation domain within STIM1 that is masked by an adjacent 31 amino acid peptide preventing efficient CRAC channel activation in cells with replete Ca2+ stores. 相似文献
13.
The putative histone H4 (F2a1) mRNA has been isolated from early blastula Strongylocentrotus purpuratus sea urchin embryos. Nucleotide sequences of oligonucleotides obtained by digestion of this RNA with T1 ribonuclease have been obtained and many are found to be colinear with the amino acid sequence of histone H4 protein. The sequences obtained from the H4 mRNAs of S. pnrpuratus have been compared with those obtained from Lytechinus pictus (Grunstein & Schedl, 1976). The two mRNAs for this highly conserved protein have undergone considerable divergence of the sort that would be predicted from the degeneracy of the genetic code. 11.5% of the bases have undergone substitution at a rate calculated to be 3 × 10?9 base changes · codon?1 · year?1. 相似文献
14.
Chi-Won CHOI Jikhyon HAN Dong-Hwan SEO Jae-Kwan RYU Seock-Yeon HWANG Sook Jae SEO Chi-Young YUN 《Entomological Research》2004,34(1):47-54
Agrius convolvuli haemolymph ferritin was purified by KBr density gradient ultracentrifugation and anion exchange column chromatography. The 670 kDa ferritin was composed of two subunits of 26 kDa and 31 kDa. It was also shown that the protein had an isoelectric point (pI) of pH 7.4. The N‐terminal amino acid sequences of the two subunits were NH2‐DNXYQDVSLDXSQAXNXL (26 kDa subunit) and NH2‐TQXHVNPVNIQRDXVTMHXS (31 kDa subunit). The sequential analysis showed that they had high similarity to lepidopteran ferritin subunits, S‐ and G‐type, respectively. Using electron microscope, it was observed that the protein had a core whose size was about 7 nm. In the amino acid composition of the protein, Glu (13.22%), Asp (10.43%), Pro (9.69%), Leu (9.63%), Ala (9.55%) and Gly (8.49%) were in relatively high contents while Tyr (1.21%), His (2.58%) and Arg (3.10 %) were in low. It was shown that the amount of ferritin in A. convolvuli haemolymph was increased by injection of eight different heavy metal ions, FeCl3, HgCl2, CuSO4, ZnSO4, MnCl2, MgCl2, CrCl3 and CdCl2. Among the ions, Fe3+, Hg2+, Zn4+, Mn2+ and Cd.2+ significantly induced the amount of the protein. 相似文献
15.
Multifunctional poly(glycidyl methacrylate) (PGMA) microspheres containing magnetic, fluorescent, and cancer cell-specific moieties were prepared in four steps: (i) preparation of parent PGMA microspheres by dispersion polymerization and their reaction with ethylenediamine to obtain amino groups, (ii) precipitation of iron ions (Fe2+ and Fe3+) to form Fe3O4 nanoparticles within the microspheres, (iii) consecutive reactions of folic acid with the amino groups on PGMA, and (iv) incorporation of fluorescein isothiocyanate into the microspheres. The microspheres were superparamagnetic, highly monodispersive, intensively fluorescent, and capable of recognizing and binding cancer cells that overexpress folic acid receptors. It was demonstrated that with these microspheres, HeLa cells could be captured from their suspension and easily moved in the direction of the externally applied magnetic field. 相似文献
16.
Representative members of a group of linear, N‐acylated polypeptide antibiotics (peptaibols) containing α‐aminoisobutyric acid (Aib) and, in part, isovaline (Iva), as well as proteinogenic amino acids and a C‐terminal‐bonded 2‐amino alcohol, were treated with anhydrous trifluoroacetic acid (TFA) at 37° for 0.5–26 h. The resulting fragments were separated by HPLC and characterized by electrospray ionization collision‐induced dissociation mass spectrometry (ESI‐CID‐MS). The following 16–20‐residue peptaibols were investigated: natural, microheterogeneous mixtures of antiamoebins and alamethicin F50, uniform paracelsin A, and synthetic trichotoxin A50/E. In the natural peptides, bonds formed between Aib (Iva) and Pro (Hyp) were rapidly and selectively cleaved within 0.5 h. Furthermore, TFA esters of the C‐terminal amino alcohols were formed. Depending on time, release of C‐terminal tri‐ and tetrapeptides as well as amino acids from the major fragments was observed. Synthetic homooligopeptides, namely Z‐ and Ac‐(Aib)10‐OtBu and Z‐(Aib)7‐OtBu, were analyzed for comparison. On treatment with TFA, a regular series of Z‐(Aib)10–5‐OH from Z‐(Aib)10‐OtBu were detected within 0.5 h, and, after 3 h, release of a regular series of Z‐(Aib)7–3‐OH from Z‐(Aib)7‐OtBu were observed. Moreover, concomitant release of the series of H‐(Aib)10–3‐OH from the decapeptide occurred. From these data, a repetitive cleavage mechanism via intermediate formation of C‐terminal oxazolones on trifluoroacetolysis is proposed. Furthermore, their formation and stability in native peptaibols are correlated with subtle structural differences in protein amino acids linked to Aib. From the conspicuous concordance of the formation and abundance of regular series of trifluoroacetolytic fragments and of positive ions of the b‐series in CID‐MS, the generation of intermediate oxazolonium ions in both gas and liquid phase is concluded. 相似文献
17.
J R Smythies F Benington R J Bradley R D Morin W O Romine 《Journal of theoretical biology》1974,47(2):383-395
A mechanism is suggested at the molecular level whereby histone IIB2 can act as a cross-link between two (or possibly three) adjacent and parallel strands of DNA double helix some 40 Å apart. Application of Prothero's rule and the Lewis probability functions indicate the probable locations of three a-helices and a number of β-turns. This, coupled with the requirement that the tertiary conformation of the histone be complementary to the DNA molecules and for as many basic groups as possible to bind to phosphate oxygens, allows us to suggest, on the basis of model building using accurate space-filling (CPK) models, a complex conformation that achieves this.A similar process applied to histone IIB1, whose complete amino acid sequence is also known, shows the location of five probable a-helices, a number of β-turns, and a segment of β-pleated sheet. The basic amino acids are gathered in four groupings. Model building experiments suggest that histone IIB1 forms a complex strut joining four parallel strands of DNA double helix that form a diamond with diameters 100 and 40 Å. In both these models the purpose and function of a fair proportion of the individual amino acids can be specified.This paper is the third and last of a series in this Journal in which models are presented for the tertiary conformation and function of all five histones of known (in whole or in part) amino acid sequence. This suggests that all five are concerned in packing the long DNA double helix, which may be in a “square helix” form, into the confined space of the chromosome. The hypotheses may be tested by a direct investigation of nucleoprotein in situ to see if these 40, 70, and 100 Å interhelical distances can be detected by biophysical methods. 相似文献
18.
The fate of alpha and epsilon lysine amino groups has been explored in rat liver homogenate by means of l-lysine labelled selectively in the two positions. α-15NH2 and ?-15NH2 are rapidly incorporated into the amino group of glutamic acid and it seems at first that both transaminations occur simultaneously. But the reversible transfer of the amino group between α-aminoadipic acid and glutamic acid, determined by means of labelled α-aminoadipic acid, proceeds swiftly, and the incorporation of α-15NH2 from the corresponding labelled lysine in glutamic acid may be easily explained by ?-transamination and saccharopine formation. The direct transamination of the α-amino group of l-lysine is most improbable and might be limited to some microorganisms and to ?-N-substituted lysine derivatives. 相似文献
19.
Anant B. Patel James C. K. Lai Golam I. M. Chowdhury Douglas L. Rothman Kevin L. Behar 《Neurochemical research》2017,42(1):173-190
The 13C turnover of neurotransmitter amino acids (glutamate, GABA and aspartate) were determined from extracts of forebrain nerve terminals and brain homogenate, and fronto-parietal cortex from anesthetized rats undergoing timed infusions of [1,6-13C2]glucose or [2-13C]acetate. Nerve terminal 13C fractional labeling of glutamate and aspartate was lower than those in whole cortical tissue at all times measured (up to 120 min), suggesting either the presence of a constant dilution flux from an unlabeled substrate or an unlabeled (effectively non-communicating on the measurement timescale) glutamate pool in the nerve terminals. Half times of 13C labeling from [1,6-13C2]glucose, as estimated by least squares exponential fitting to the time course data, were longer for nerve terminals (GluC4, 21.8 min; GABAC2 21.0 min) compared to cortical tissue (GluC4, 12.4 min; GABAC2, 14.5 min), except for AspC3, which was similar (26.5 vs. 27.0 min). The slower turnover of glutamate in the nerve terminals (but not GABA) compared to the cortex may reflect selective effects of anesthesia on activity-dependent glucose use, which might be more pronounced in the terminals. The 13C labeling ratio for glutamate-C4 from [2-13C]acetate over that of 13C-glucose was twice as large in nerve terminals compared to cortex, suggesting that astroglial glutamine under the 13C glucose infusion was the likely source of much of the nerve terminal dilution. The net replenishment of most of the nerve terminal amino acid pools occurs directly via trafficking of astroglial glutamine. 相似文献
20.
The molecular conformations of the linear oligopeptides H-(L -Ala)n-L -Pro-OH, with n = 1,2 and 3, have been investigated. 13C nmr observation of the equilibrium between the cis and trans forms of the Ala-Pro peptide bond indicated the occurrence of nonrandom conformations in solutions of these flexible peptides. The formation of the nonrandom species containing the cis form of the Ala-Pro bond was found to depend on the deprotonation of the carboxylic acid group of proline, the solvent, and the ionic strength in aqueous solution. The influence of intramolecular hydrogen bonding on the relative conformational energies of the species containing the cis and trans Ala-Pro peptide bond was studied by comparison of the peptides H-(Ala)n-Pro-OH with analogous molecules where hydrogen bond formation was excluded by the covalent structure. In earlier work a hydrogen bond between the protonated terminal carboxylic acid group and the carbonyl oxygen of the penultimate amino acid residue had been suggested to stabilize conformations including trans proline. For the systems described here this hypothesis can be ruled out, since the cis:trans ratio is identical for molecules with methyl ester protected and free protonated terminal carboxylic acid groups of proline. Direct evidence for hydrogen bond formation between the deprotonated terminal carboxylic acid group and the amide proton of the penultimate amino acid residue in the molecular species containing cis proline was obtained from 1H nmr studies. However, the cis:trans ratio of the Ala-Pro bond was not affected by N-methylation of the penultimate amino acid residue, which prevents formation of this hydrogen bond. Overall the experimental observations lead to the conclusion that the relative energies of the peptide conformations including cis or trans proline are mainly determined by intramolecular electrostatic interactions, whereas in the molecules considered, intramolecular hydrogen bonding is a consequence of specific peptide backbone conformations rather than a cause for the occurrence of energetically favored species. Independent support for this conclusion was obtained from model consideration which indicated that electrostatic interactions between the terminal carboxylic acid group and the carbonyl oxygen of the penultimate amino acid residue could indeed account for the observed relative conformational energies of the species containing cis and trans proline, respectively. 相似文献