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Two new modified uracil nucleosides, 5-carbamoylmethyuridine (ncm5U, I) and 5-carbamoylmethyl-2-thiouridine (ncm5s2U, II) were isolated from a 24 hr collection of a normal human urine. The structures were assigned on the basis of UV, NMR and mass spectral data and confirmed by comparison of the spectral data and HPLC mobilities with those of authentic samples. On the basis of experimental data it appears possible that 5-carbamoylmethyl-2-thio-uridine (ncm5s2U, II) may be a degradation product produced from a labile precursor by the chemical treatments during the isolation procedure. However, the other nucleoside (ncm5U,I) certainly appears to be of metabolic origin and was also found in the urines of one chronic myelogenous leukemia and one lung carcinoma patient. Abbreviations used are: tRNA-transfer ribonucleic acid, TMS-trimethylsilyl, RP-HPLC--reverse phase high performance liquid chromatography, EI--electron impact, cm5U-5-carboxymethyluridine, mcm5U-5-methoxycarbonylmethyluridine, cm5s2U-5-carboxymethyl-2-thiouridine, mcm5s2U-5-methoxycarbonylmethyl-2-thiouridine, t6A-9-beta-D-ribofuranosyl-[N(purin-6-yl)carbamoyl]-1-threonine, C-cytidine, acp3u-3-(3-amino-3-carboxypropyl)uridine, AICR-aminoimidazole carboxamide riboside, alpha-4-PCNR & beta-4-PCNR-9-alpha-D-(or beta-D)-ribofuranosyl-pyridin-4-one-3-carboxamide, H x 7R-7-beta-D-ribofuranosyl hypoxanthine, m3U-3-methyluridine, m1I-1-methylinosine, m1G-1-methylguanosine, DI-5'-deoxyinosine, dms5OA-5'-deoxy-5'-methylthioadenosine sulfoxide, m2(2)G-N2-dimethylguanosine, psi-psi-uridine, A-adenosine, I-inosine, CML-chronic myelogenous leukemia mam5s2U-5-methylaminomethyl-2-thiouridine, ncm5U-5-carbamoylmethyluridine, ncm5s2U-5-carbamoylmethyl-2-thiouridine, UV-ultraviolet, NMR-nuclear magnetic resonance, HPLC-high performance liquid chromatography, GC-MS-gas chromatography-mass spectrometry. 相似文献
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Girish B. Chhed Helen B. Patrzyc Arvind K. Bhargava Pamela F. Crain Satinder K. Sethi James A. McCloskey 《Nucleosides, nucleotides & nucleic acids》2013,32(3):597-611
Abstract From 24 hour collections of urines of chronic myelogenous leukemia (CML) patients, a novel nucleoside was isolated. It was assigned the structure, 5′-deoxyinosine (I) on the basis of UV, NMR and mass spectrometry and by comparison of the spectral data and HPLC and TLC mobilities with those of the authentic sample. Another nucleoside, 5′-deoxy-5′-methylthioadenosine sulfoxide previously isolated from the urines of immunodeficient children was also found in the urine of a CML patient. Possible origin and significance of both of these nucleosides are discussed. 相似文献
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Large, rapidly evolving intergenic spacers in the mitochondrial DNA of the salamander family Ambystomatidae (Amphibia: Caudata) 总被引:5,自引:2,他引:3
We report the presence, in the mitochondrial DNA (mtDNA) of all of the
sexual species of the salamander family Ambystomatidae, of a shared 240- bp
intergenic spacer between tRNAThr and tRNAPro. We place the intergenic
spacer in context by presenting the sequence of 1,746 bp of mtDNA from
Ambystoma tigrinum tigrinum, describe the nucleotide composition of the
intergenic spacer in all of the species of Ambystomatidae, and compare it
to other coding and noncoding regions of Ambystoma and several other
vertebrate mtDNAs. The nucleotide substitution rate of the intergenic
spacer is approximately three times faster than the substitution rate of
the control region, as shown by comparisons among six Ambystoma
macrodactylum sequences and eight members of the Ambystoma tigrinum
complex. We also found additional inserts within the intergenic spacers of
five species that varied from 87-444 bp in length. The presence of the
intergenic spacer in all sexual species of Ambystomatidae suggests that it
arose at least 20 MYA and has been a stable component of the ambystomatid
mtDNA ever since. As such, it represents one of the few examples of a large
and persistent intergenic spacer in the mtDNA of any vertebrate clade.
相似文献
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A single free radical-initiating event can produce a pair of base lesions in DNA oligomers exposed to ionizing radiation. Whereas double base lesions have been observed previously, the present study shows that double lesions may sometimes consist of a base lesion and an associated strand break. The mechanism for the formation of double lesions is discussed. A redox process is postulated in which guanine is the source of the electron. It is suggested that double lesions may be formed in DNA either on adjacent nucleotides or, alternatively, on nucleotides separated by one, two or possibly more intervening nucleotides. It is hypothesized that intramolecular electron transfer facilitates the formation of double lesions on nonadjacent nucleotides. 相似文献
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Greene KF Budzinski EE Iijima H Dawidzik JB DeFedericis HC Patrzyc HB Evans MS Bailey DT Freund HG Box HC 《Radiation research》2007,167(2):146-151
UVC-radiation-induced DNA damage was measured in mouse fibroblast cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conjunction with isotopically labeled internal standards. The thymine glycol and formamide lesions were assayed in the form of modified dinucleoside monophosphates. The 8-oxo-7,8-dihydroguanine lesion was measured as the modified nucleoside. DNA damage in cells treated with tirapazamine was also measured. Tirapazamine is a chemotherapeutic agent that acts via a free radical mechanism. The two agents, UVC radiation and tirapazamine, produce markedly different profiles of DNA damage, reflecting their respective mechanisms of action. Both agents produce significant amounts of thymine glycol and formamide damage, but only the former produced a measurable amount of the 8-oxo-7,8-dihydroguanine lesion. The merits of measuring DNA damage at the dimer level are discussed. 相似文献
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DeFedericis HC Patrzyc HB Rajecki MJ Budzinski EE Iijima H Dawidzik JB Evans MS Greene KF Box HC 《Radiation research》2006,165(4):445-451
Singlet oxygen, hydrogen peroxide, hydroxyl radical and hydrogen peroxide are the reactive oxygen species (ROS) considered most responsible for producing oxidative stress in cells and organisms. Singlet oxygen interacts preferentially with guanine to produce 8-oxo-7,8-dihydroguanine and spiroiminodihydantoin. DNA damage due to the latter lesion has not been detected directly in the DNA of cells exposed to singlet oxygen. In this study, the singlet oxygen-induced lesion was isolated from a short synthetic oligomer after exposure to UVA radiation in the presence of methylene blue. The lesion could be enzymatically excised from the oligomer in the form of a modified dinucleoside monophosphate. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), the singlet oxygen lesion was detected in the form of modified dinucleoside monophosphates in double-stranded DNA and in the DNA of HeLa cells exposed to singlet oxygen. Pentamer containing the singlet oxygen-induced lesion and an isotopic label was synthesized as an internal standard for quantifying the lesion and served as well as for correcting for losses of product during sample preparation. 相似文献
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Alexander E. Maccubbin Edwin E. Budzinski Helen Patrzyc Marianne S. Evans Noreen Ersing Harold C. Box 《Free radical research》1993,18(1):17-28
A prominent lesion in DNA exposed to oxidative free radicals results from the degradation of thymine leaving a formamido remnant. A 32P-postlabeling assay has been developed for the detection of the formamido lesion. The assay is based on the circumstance that the lesion prevents hydrolysis by nuclease PI of the phosphoester bond 3' to the damaged nucleoside. Thus, a nuclease PI plus acid phosphatase digest of DNA generates mostly nucleosides whereas the formamido lesion is rendered as a modified dinucleoside monophosphate. Dinucleoside monophosphates, but not nucleosides, are apt substrates for 32P-postlabeling by polynucleotide kinase. The assay was applied to calf thymus DNA X-irradiated in oxygenated solution. The formamido lesion could be detected down to a dose of a few Gy. 相似文献
10.
A simple, fast and sensitive method was developed to verify the presence of
the sialyl Lewis(x) antigen on an N-linked glycoprotein. High performance
liquid chromatography-electrospray mass spectrometry (HPLC-ESI/MS) was used
to identify which of the five N-linked glycosylation sites of human plasma
alpha1-acid-glycoprotein (orosomucoid, OMD) contain the sialyl Lewis(x)
antigen. OMD was digested with proteolytic enzymes and analyzed by reversed
phase chromatography coupled with on-line ESI/MS. A tandem mass
spectrometry experiment was designed to detect the presence of the sialyl
Lewis(x) antigen based on the observation of an 803 mass to charge ratio (
m/z ) ion produced in the intermediate pressure region of the ESI
interface. The ESI/MS signal at m/z 803 is consistent with an oxonium ion
for a glycan structure containing NeuAc, Gal, GlcNAc, and Fuc. The identity
of the m/z 803 ion was confirmed by ESI/MS/MS analysis of the m/z 803
fragment ion and comparison with a sialyl Lewis(x) standard. The
stereochemistry and linkage positions were assigned using previous NMR
analysis but could be determined with permethylation analysis if necessary.
The analysis of OMD gave a pattern showing signal for the sialyl Lewis(x)
antigen coeluting with each of the five N-linked glycopeptides. The ability
to monitor sialyl Lewis(x) expression at each of the five sites is of
interest in the study of OMD's role in inflammatory diseases.
相似文献