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1.
Epidemiol Infect ; 150: e172, 2022 09 13.
Article in English | MEDLINE | ID: mdl-36097692

ABSTRACT

While tetanus toxoid vaccination has reduced the incidence of tetanus in the developed world, this disease remains a substantial health problem in developing nations. Tetanus immune globulin (TIG) is used along with vaccination for prevention of infection after major or contaminated wounds if vaccination status cannot be verified or for active tetanus infection. These studies describe the characterisation of a TIG produced by a caprylate/chromatography process. The TIG potency and presence of plasma protein impurities were analysed at early/late steps in the manufacturing process by chromatography, immunoassay, coagulation and potency tests. The caprylate/chromatography process has been previously shown to effectively eliminate or inactivate potentially transmissible agents from plasma-derived products. In this study, the caprylate/chromatography process was shown to effectively concentrate TIG activity and efficiently remove pro-coagulation factors, naturally present in plasma. This TIG drug product builds on the long-term evidence of the safety and efficacy of TIG by providing a product with higher purity and low pro-coagulant protein impurities.


Subject(s)
Tetanus , Humans , Tetanus/prevention & control , Tetanus Toxoid , Caprylates , Tetanus Antitoxin/analysis , Tetanus Antitoxin/therapeutic use , Chromatography
2.
J Immunol Methods ; 499: 113164, 2021 12.
Article in English | MEDLINE | ID: mdl-34624302

ABSTRACT

BACKGROUND: Human rabies immunoglobulin (RIG) is an integral part of post-exposure prophylactic treatment of rabies (along with rabies vaccination). Infiltration of most, if not all, of the RIG dose at the wound site is recommended. RIG produced by a caprylate/chromatography manufacturing process (RIG-C; HyperRAB) increased the potency and purity of this product over the existing licensed RIG from a solvent/detergent process (RIG-S/D; HyperRAB-S/D). METHODS: A series of studies were conducted to characterize the content and purity of RIG-C. A single-dose pharmacokinetic study in rabbits was performed to compare intramuscular (IM) immunoglobulin products manufactured by two different purification processes, solvent/detergent (IGIM-S/D) and caprylate/chromatography (IGIM-C). RESULTS: RIG-C was found to be a highly purified IgG formulation with high monomer content and formulated with twice the anti-rabies potency of RIG-S/D while maintaining the same overall protein concentration. RIG-C facilitates IM administration at the wound site by halving the injection volume. The new caprylate/chromatography process eliminated detectible levels of pro-coagulant impurities and IgA that were carried through in the prior S/D process. These impurities have been associated with thrombotic complications and allergic reactions in susceptible patients. After single dose administration, IGIM-C was pharmacokinetically equivalent to IGIM-S/D in rabbits. CONCLUSION: RIG-C is a more potent RIG formulation with less impurities yielding a safer and more convenient product with similar pharmacokinetic profile.


Subject(s)
Caprylates/chemistry , Globulins/analysis , Chromatography , Globulins/immunology , Humans , Rabies virus/immunology
3.
Transfusion ; 61(6): 1705-1709, 2021 06.
Article in English | MEDLINE | ID: mdl-33715160

ABSTRACT

BACKGROUND: In late 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus emerged in China and quickly spread into a worldwide pandemic. Prior to the development of specific drug therapies or a vaccine, more immediately available treatments were sought including convalescent plasma. A potential improvement from convalescent plasma could be the preparation of anti-SARS-CoV-2 hyperimmune globulin (hIVIG). STUDY DESIGN AND METHODS: Convalescent plasma was collected from an existing network of plasma donation centers. A caprylate/chromatography purification process was used to manufacture hIVIG. Initial batches of hIVIG were manufactured in a versatile, small-scale facility designed and built to rapidly address emerging infectious diseases. RESULTS: Processing convalescent plasma into hIVIG resulted in a highly purified immunoglobulin G (IgG) product with more concentrated neutralizing antibody activity. hIVIG will allow for the administration of greater antibody activity per unit of volume with decreased potential for several adverse events associated with plasma administration. IgG concentration and IgG specific to SARS-CoV-2 were increased over 10-fold from convalescent plasma to the final product. Normalized enzyme-linked immunosorbent assay activity (per mg/ml IgG) was maintained throughout the process. Protein content in these final product batches was 100% IgG, consisting of 98% monomer and dimer forms. Potentially hazardous proteins (IgM, IgA, and anti-A, anti-B, and anti-D) were reduced to minimal levels. CONCLUSIONS: Multiple batches of anti-SARS-CoV-2 hIVIG that met regulatory requirements were manufactured from human convalescent plasma. The first clinical study in which the hIVIG will be evaluated will be Inpatient Treatment with Anti-Coronavirus Immunoglobulin (ITAC) [NCT04546581].


Subject(s)
COVID-19/immunology , COVID-19/therapy , Convalescence , SARS-CoV-2/immunology , ABO Blood-Group System/immunology , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Blood Component Transfusion/methods , Blood Donors , Blood Specimen Collection/methods , COVID-19/blood , COVID-19/epidemiology , China/epidemiology , Enzyme-Linked Immunosorbent Assay , Humans , Immunization, Passive/methods , Immunoglobulin G/blood , Pandemics , COVID-19 Serotherapy
4.
Biologicals ; 64: 34-40, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32085977

ABSTRACT

Immune globulin subcutaneous, human 20% solution (IGSC-C 20%, Xembify®)-a new 20% immunoglobulin (IgG) liquid product for subcutaneous (SC) administration-has been developed by Grifols. The IGSC-C 20% formulation is based on knowledge acquired from the formulation of Immune Globulin Injection (Human),10% Caprylate/Chromatography Purified (IGIV-C 10%, Gamunex®-C). The protein concentration was increased from 10% to 20% to provide a smaller volume for SC administration. The IGSC-C 20% manufacturing process employs the same caprylate/chromatography purification steps as IGIV-C 10%, with the addition of an ultrafiltration step so that the product can be formulated at a higher protein concentration. IGSC-C 20% has been produced at full industrial scale to support clinical studies and licensure. These batches were characterized using a comprehensive panel of analytical testing. The new IGSC-C 20% product maintains the same composition, neutralizing activity, purity, and quality characteristics found in IGIV-C 10%.


Subject(s)
Immunoglobulin G , Humans , Immunoglobulin G/chemistry , Immunoglobulin G/isolation & purification , Injections, Subcutaneous
5.
Biologicals ; 62: 77-84, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31522909

ABSTRACT

Multiple analytical and preclinical studies were performed to compare the biochemical characteristics, pharmacokinetics (PK), safety and neoantigenicity of a new 5% liquid formulation of Alpha-1 Proteinase Inhibitor (Liquid A1PI, Prolastin®-C Liquid) with the lyophilized version (Lyophilized A1PI, Prolastin®-C). Liquid A1PI and Lyophilized A1PI had similar average mass (~52 kDa), and both forms exhibited glycoform patterns consistent with the known banding pattern of A1PI (dominated by the M6 and M4 bands, including deconvoluted masses). Both Liquid A1PI and Lyophilized A1PI yielded average percent purity values ranging from 96% to 99% and had active content ranging from 53  mg/mL to 59  mg/mL. The PK profile of Liquid A1PI was similar to Lyophilized A1PI. Safety assessments in rabbits showed good tolerability and no test article-related changes in mortality, clinical signs, clinical pathology, body weight, food consumption, or urinalysis parameters. Following immunodepletion of antibodies that recognize Lyophilized A1PI, there were no significant differences in the anti-drug titers among animals immunized with Lyophilized A1PI and Liquid A1PI (p > 0.05), indicating that no antibodies to neoantigens were generated. Liquid A1PI and Lyophilized A1PI have similar profiles with respect to biochemical characteristics, PK, safety and neoantigenicity.


Subject(s)
alpha 1-Antitrypsin Deficiency/drug therapy , alpha 1-Antitrypsin , Animals , Antibodies/blood , Antibodies/immunology , Freeze Drying , Humans , Rabbits , alpha 1-Antitrypsin/adverse effects , alpha 1-Antitrypsin/immunology , alpha 1-Antitrypsin/pharmacokinetics , alpha 1-Antitrypsin/pharmacology , alpha 1-Antitrypsin Deficiency/blood , alpha 1-Antitrypsin Deficiency/immunology
6.
J Mol Biol ; 373(2): 282-95, 2007 Oct 19.
Article in English | MEDLINE | ID: mdl-17822711

ABSTRACT

UvrB is a central DNA damage recognition protein involved in bacterial nucleotide excision repair. Structural information has been limited by the apparent disorder of the C-terminal domain 4 in crystal structures of intact UvrB; in solution, the isolated domain 4 is found to form a helix-loop-helix dimer. In order to gain insight into the behavior of UvrB in solution, we have performed NMR studies on [methyl-13C]methionine-labeled UvrB from Bacillus caldotenax (molecular mass=75 kDa). The 13 methyl resonances were assigned on the basis of site-directed mutagenesis and domain deletion. Solvent accessibility was assessed based on the relaxation and chemical shift responses of the probe methyl resonances to the stable nitroxide, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL). M632, located at the potential dimer interface of domain 4, provides an ideal probe for UvrB dimerization behavior. The M632 resonance of UvrB is very broad, consistent with some degree of monomer-dimer exchange and/or conformational instability of the exposed dimer interface. Upon addition of unlabeled domain 4 peptide, the M632 resonance of UvrB sharpens and shifts to a position consistent with a UvrB-domain 4 heterodimer. A dissociation constant (KD) value of 3.3 microM for the binding constant of UvrB with the domain 4 peptide was derived from surface plasmon resonance studies. Due to the flexibility of the domain 3-4 linker, inferred from limited proteolysis data and from the relaxation behavior of linker residue M607, the position of domain 4 is constrained not by the stiffness of the linking segment but by direct interactions with domains 1-3 in UvrB. In summary, UvrB homodimerization is disfavored, while domain 4 homodimerization and UvrB-domain 4 heterodimerization are allowed.


Subject(s)
Bacillus/enzymology , Bacterial Proteins/chemistry , DNA Repair Enzymes/chemistry , Bacterial Proteins/metabolism , Binding Sites , Carbon Isotopes , DNA Repair Enzymes/metabolism , Dimerization , Methionine/chemistry , Methionine/metabolism , Models, Biological , Models, Molecular , Mutagenesis, Site-Directed , Nuclear Magnetic Resonance, Biomolecular , Protein Structure, Tertiary , Solutions , Surface Plasmon Resonance
7.
Chem Res Toxicol ; 20(2): 187-98, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17256975

ABSTRACT

The 1,4-bis(2'-deoxyadenosin-N(6)-yl)-2S,3S-butanediol intrastrand DNA cross-link arises from the bis-alkylation of tandem N(6)-dA sites in DNA by R,R-butadiene diepoxide (BDO(2)). The oligodeoxynucleotide 5'-d(C(1)G(2)G(3)A(4)C(5)X(6)Y(7)G(8)A(9)A(10)G(11))-3'.5'-d(C(12)T(13)T(14)C(15)T(16)T(17)G(18)T(19)C(20)C(21)G(22))-3' contains the BDO(2) cross-link between the second and third adenines of the codon 61 sequence (underlined) of the human N-ras protooncogene and is named the (S,S)-BD-(61-2,3) cross-link (X,Y = cross-linked adenines). NMR analysis reveals that the cross-link is oriented in the major groove of duplex DNA. Watson-Crick base pairing is perturbed at base pair X(6).T(17), whereas base pairing is intact at base pair Y(7).T(16). The cross-link appears to exist in two conformations, in rapid exchange on the NMR time scale. In the first conformation, the beta-OH is predicted to form a hydrogen bond with T(16) O(4), whereas in the second, the beta-OH is predicted to form a hydrogen bond with T(17) O(4). In contrast to the (R,R)-BD-(61-2,3) cross-link in the same sequence (Merritt, W. K., Nechev, L. V., Scholdberg, T. A., Dean, S. M., Kiehna, S. E., Chang, J. C., Harris, T. M., Harris, C. M., Lloyd, R. S., and Stone, M. P. (2005) Biochemistry 44, 10081-10092), the anti-conformation of the two hydroxyl groups at C(beta) and C(gamma) with respect to the C(beta)-C(gamma) bond results in a decreased twist between base pairs X(6).T(17) and Y(7).T(16), and an approximate 10 degrees bending of the duplex. These conformational differences may account for the differential mutagenicity of the (S,S)- and (R,R)-BD-(61-2,3) cross-links and suggest that stereochemistry plays a role in modulating biological responses to these cross-links (Kanuri, M., Nechev, L. V., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580).


Subject(s)
Codon/chemistry , DNA Adducts/chemistry , Epoxy Compounds/chemistry , Genes, ras/genetics , Butylene Glycols , Deoxyadenosines , Humans , Magnetic Resonance Spectroscopy/methods , Magnetic Resonance Spectroscopy/standards , Models, Molecular , Molecular Structure , Oligodeoxyribonucleotides/chemistry , Reference Standards , Sensitivity and Specificity , Structure-Activity Relationship
8.
Biochemistry ; 44(30): 10081-92, 2005 Aug 02.
Article in English | MEDLINE | ID: mdl-16042385

ABSTRACT

The solution structure of the 1,4-bis(2'-deoxyadenosin-N(6)-yl)-2R,3R-butanediol cross-link arising from N(6)-dA alkylation of nearest-neighbor adenines by butadiene diepoxide (BDO(2)) was determined in the oligodeoxynucleotide 5'-d(CGGACXYGAAG)-3'.5'-d(CTTCTTGTCCG)-3'. This oligodeoxynucleotide contained codon 61 (underlined) of the human N-ras protooncogene. The cross-link was accommodated in the major groove of duplex DNA. At the 5'-side of the cross-link there was a break in Watson-Crick base pairing at base pair X(6).T(17), whereas at the 3'-side of the cross-link at base pair Y(7).T(16), base pairing was intact. Molecular dynamics calculations carried out using a simulated annealing protocol, and restrained by a combination of 338 interproton distance restraints obtained from (1)H NOESY data and 151 torsion angle restraints obtained from (1)H and (31)P COSY data, yielded ensembles of structures with good convergence. Helicoidal analysis indicated an increase in base pair opening at base pair X(6).T(17), accompanied by a shift in the phosphodiester backbone torsion angle beta P5'-O5'-C5'-C4' at nucleotide X(6). The rMD calculations predicted that the DNA helix was not significantly bent by the presence of the four-carbon cross-link. This was corroborated by gel mobility assays of multimers containing nonhydroxylated four-carbon N(6),N(6)-dA cross-links, which did not predict DNA bending. The rMD calculations suggested the presence of hydrogen bonding between the hydroxyl group located on the beta-carbon of the four-carbon cross-link and T(17) O(4), which perhaps stabilized the base pair opening at X(6).T(17) and protected the T(17) imino proton from solvent exchange. The opening of base pair X(6).T(17) altered base stacking patterns at the cross-link site and induced slight unwinding of the DNA duplex. The structural data are interpreted in terms of biochemical data suggesting that this cross-link is bypassed by a variety of DNA polymerases, yet is significantly mutagenic [Kanuri, M., Nechev, L. V., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580].


Subject(s)
Alkylating Agents/chemistry , Butadienes/chemistry , Butylene Glycols/chemistry , Codon/metabolism , DNA Adducts/chemistry , Deoxyadenosines/chemistry , Epoxy Compounds/chemistry , Genes, ras/drug effects , Base Pairing/drug effects , Butadienes/pharmacology , Cross-Linking Reagents/chemistry , Epoxy Compounds/pharmacology , Humans , Mutagens/chemistry , Nuclear Magnetic Resonance, Biomolecular , Nucleic Acid Heteroduplexes/chemistry , Oligodeoxyribonucleotides/chemistry , Protons
9.
Chem Res Toxicol ; 18(7): 1098-107, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16022502

ABSTRACT

The solution structure of the N1-[1-hydroxy-3-buten-2(R)-yl]-2'-deoxyinosine adduct arising from the alkylation of adenine N1 by butadiene epoxide (BDO), followed by deamination to deoxyinosine, was determined in the oligodeoxynucleotide 5'-d(CGGACXAGAAG)-3'.5'-d(CTTCTTGTCCG)-3'. This oligodeoxynucleotide contained the BDO adduct at the second position of codon 61 of the human N-ras protooncogene (underlined) and was named the ras61 R-N1-BDO-(61,2) adduct. 1H NMR revealed a weak C5 H1' to X6 H8 nuclear Overhauser effects (NOE), followed by an intense X6 H8 to X6 H1' NOE. Simultaneously, the X6 H8 to X6 H3' NOE was weak. The resonances arising from the T16 and T17 imino protons were not observed. 1H NOEs between the butadiene moiety and the DNA positioned the adduct in the major groove. Structural refinement based upon a total of 394 NOE-derived distance restraints and 151 torsion angle restraints yielded a structure in which the modified deoxyinosine was in the syn conformation about the glycosyl bond, with a glycosyl bond angle of 83 degrees , and T17, the complementary nucleotide, was stacked into the helix but not hydrogen bonded with the adducted inosine. The refined structure provides a plausible hypothesis as to why these N1 deoxyinosine adducts strongly code for the incorporation of dCTP during trans lesion DNA replication, irrespective of stereochemistry, both in Escherichia coli [Rodriguez, D. A., Kowalczyk, A., Ward, J. B. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2001) Environ. Mol. Mutagen. 38, 292-296] and in mammalian cells [Kanuri, M., Nechev, L. N., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580]. Rotation of the N1 deoxyinosine adduct into the syn conformation may facilitate incorporation of dCTP via Hoogsteen type templating with deoxyinosine, generating A to G mutations. However, conformational differences between the R- and the S-N1-BDO-(61,2) adducts, involving the positioning of the butenyl moiety in the major groove of DNA, suggest that adduct stereochemistry plays a secondary role in modulating the biological response to these adducts.


Subject(s)
Butadienes/chemistry , Hydrogen/chemistry , Inosine/analogs & derivatives , Oxygen/chemistry , Alkylation , DNA/chemistry , Glycosylation , Inosine/chemistry , Magnetic Resonance Spectroscopy , Molecular Conformation , Protons , Stereoisomerism
10.
Biochemistry ; 44(9): 3327-37, 2005 Mar 08.
Article in English | MEDLINE | ID: mdl-15736943

ABSTRACT

The solution structure of the N1-(1-hydroxy-3-buten-2(S)-yl)-2'-deoxyinosine adduct arising from the alkylation of adenine N1 by butadiene epoxide (BDO), followed by deamination to deoxyinosine, was determined, in the oligodeoxynucleotide d(CGGACXAGAAG).d(CTTCTCGTCCG). This oligodeoxynucleotide contained the BDO adduct at the second position of codon 61 of the human N-ras protooncogene, and was named the ras61 S-N1-BDO-(61,2) adduct. (1)H NMR revealed a weak C(5) H1' to X(6) H8 NOE, followed by an intense X(6) H8 to X(6) H1' NOE. Simultaneously, the X(6) H8 to X(6) H3' NOE was weak. The resonance arising from the T(17) imino proton was not observed. (1)H NOEs between the butadiene moiety and the DNA positioned the adduct in the major groove. Structural refinement based upon a total of 364 NOE-derived distance restraints yielded a structure in which the modified deoxyinosine was in the high syn conformation about the glycosyl bond, and T(17), the complementary nucleotide, was stacked into the helix, but not hydrogen bonded with the adducted inosine. The refined structure provided a plausible hypothesis as to why this N1 deoxyinosine adduct strongly coded for the incorporation of dCTP during trans lesion DNA replication, both in Escherichia coli [Rodriguez, D. A., Kowalczyk, A., Ward, J. B. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2001) Environ. Mol. Mutagen. 38, 292-296], and in mammalian cells [Kanuri, M., Nechev, L. N., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580]. Rotation of the N1 deoxyinosine adduct into the high syn conformation may facilitate incorporation of dCTP via Hoogsteen-type templating with deoxyinosine, thus generating A-to-G mutations.


Subject(s)
Butadienes/chemistry , Codon/chemistry , Codon/genetics , DNA Adducts/chemistry , Epoxy Compounds/chemistry , Genes, ras/genetics , Inosine/analogs & derivatives , Inosine/chemistry , Oligodeoxyribonucleotides/chemistry , Alkylating Agents/chemistry , Alkylating Agents/metabolism , Base Sequence , Butadienes/metabolism , Codon/metabolism , DNA Adducts/genetics , DNA Adducts/metabolism , Epoxy Compounds/metabolism , Humans , Inosine/genetics , Inosine/metabolism , Magnetic Resonance Spectroscopy/methods , Models, Molecular , Mutagenesis, Site-Directed , Nucleic Acid Conformation , Oligodeoxyribonucleotides/genetics , Oligodeoxyribonucleotides/metabolism , Protons , Thermodynamics
11.
Chem Res Toxicol ; 18(2): 145-53, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15720118

ABSTRACT

The (2S,3S)-N6-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl (BDT) adduct arising from alkylation of adenine N6 by butadiene diol epoxide (BDE) was placed opposite a mismatched deoxyguanosine nucleotide in the complementary strand of the oligodeoxynucleotide 5'-d(CGGACXAGAAG)-3'.5'-d(CTTCTGGTCCG)-3'. This oligodeoxynucleotide contains codon 61 (underlined) of the human N-ras protooncogene. The BDT adduct was at the second position of codon 61, and this was named the ras61 S,S-BDT-(61,2) A.G adduct. NMR spectroscopy revealed the presence of two conformations of the adducted mismatched duplex. In the major conformation, the mismatched base pair X6.G17 was oriented in a "face-to-face" orientation, in which both the modified nucleotide X6 and its complement G17 were intrahelical and in the anti conformation about the glycosyl bond. Hydrogen bonding was suggested between X6 N1 and G17 N1H and between X6 N6H and G17 O6. The presence of the BDT moiety allowed formation of a stable A.G mismatch pair. The identity of the minor conformation could not be determined. If not repaired, the resulting mismatch pair would generate A-->C mutations, which have been associated with this adenine N6 BDT adduct [Carmical, J. R., Nechev, L. N., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2000) Env. Mol. Mutagen. 35, 48-56].


Subject(s)
Base Pair Mismatch , Butadienes/chemistry , DNA Adducts/chemistry , Deoxyadenosines/chemistry , Epoxy Compounds/chemistry , Glycols/chemistry , Humans , Hydrogen Bonding , Hydrogen-Ion Concentration , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation , Oligodeoxyribonucleotides/chemical synthesis , Poly U , Protons
12.
Chem Res Toxicol ; 17(8): 1007-19, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15310233

ABSTRACT

Butadiene is oxidized in vivo to form stereoisomeric butadiene diol epoxides (BDE). These react with adenine N(6) in DNA yielding stereoisomeric N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl (BDT) adducts. When replicated in Escherichia coli, the (2R,3R)-N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl adduct yielded low levels of A-->G mutations whereas the (2S,3S)-N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl butadiene triol adduct yielded low levels of A-->C mutations [Carmical, J. R., Nechev, L. V., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2000) Environ. Mol. Mutagen. 35, 48-56]. Accordingly, the structure of the (2R,3R)-N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl adduct at position X(6) in d(CGGACXAGAAG).d(CTTCTTGTCCG), the ras61 R,R-BDT-(61,2) adduct, was compared to the corresponding structure for the (2S,3S)-N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl adduct in the same sequence, the ras61 S,S-BDT-(61,2) adduct. Both the R,R-BDT-(61,2) and S,S-BDT-(61,2) adducts are oriented in the major groove of the DNA, accompanied by modest structural perturbations. However, structural refinement of the two adducts using a simulated annealing restrained molecular dynamics (rMD) approach suggests stereospecific differences in hydrogen bonding between the hydroxyl groups located at the beta- and gamma-carbons of the BDT moiety, and T(17) O(4) of the modified base pair X(6).T(17). The rMD calculations predict hydrogen bond formation between the gamma-OH and the T(17) O(4) in the R,R-BDT-(61,2) adduct whereas in the S,S-BDT-(61,2) adduct, hydrogen bond formation is predicted between the beta-OH and the T(17) O(4). This difference positions the two adducts differently in the major groove. This may account for the differential mutagenicity of the two adducts and suggests that the two adducts may interact differentially with other DNA processing enzymes. With respect to mutagenesis in E. coli, the minimal perturbation of DNA induced by both major groove adducts correlates with their facile bypass by three E. coli DNA polymerases in vitro and may account for their weak mutagenicity [Carmical, J. R., Nechev, L. V., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2000) Environ. Mol. Mutagen. 35, 48-56].


Subject(s)
Butadienes/chemistry , Butanols/chemistry , DNA Adducts/chemistry , Adenine/chemistry , Adenine/metabolism , Animals , Base Sequence , Butadienes/metabolism , Butadienes/toxicity , Epoxy Compounds/chemistry , Escherichia coli/chemistry , Magnetic Resonance Spectroscopy , Molecular Sequence Data , Mutagenicity Tests , Nucleic Acid Heteroduplexes/chemistry , Protons , Stereoisomerism , Thermodynamics
13.
Chem Res Toxicol ; 17(6): 717-30, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15206893

ABSTRACT

The solution structure of the (2S,3S)-N(6)-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl adduct arising from the alkylation of adenine N(6) at position X(6) in d(CGGACXAGAAG).d(CTTCTTGTCCG), by butadiene diol epoxide, was determined. This oligodeoxynucleotide contains codon 61 (underlined) of the human N-ras protooncogene. This oligodeoxynucleotide, containing the adenine N(6) adduct butadiene triol (BDT) adduct at the second position of codon 61, was named the ras61 S,S-BDT-(61,2) adduct. NMR spectroscopy revealed modest structural perturbations localized to the site of adduction at X(6).T(17), and its nearest-neighbor base pairs C(5).G(18) and A(7).T(16). All sequential NOE connectivities arising from DNA protons were observed. Torsion angle analysis from COSY data suggested that the deoxyribose sugar at X(6) remained in the C2'-endo conformation. Molecular dynamics calculations using a simulated annealing protocol restrained by a total of 442 NOE-derived distances and J coupling-derived torsion angles refined structures in which the BDT moiety oriented in the major groove. Relaxation matrix analysis suggested hydrogen bonding between the hydroxyl group located at the beta-carbon of the BDT moiety and the T(17) O(4) of the modified base pair X(6).T(17). The minimal perturbation of DNA induced by this major groove adduct correlated with its facile bypass by three Escherichia coli DNA polymerases in vitro and its weak mutagenicity [Carmical, J. R., Nechev, L. V., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2000) Environ. Mol. Mutagen. 35, 48-56]. Overall, the structure of this adduct is consistent with an emerging pattern in which major groove adenine N(6) alkylation products of styrene and butadiene oxides that do not strongly perturb DNA structure are not strongly mutagenic.


Subject(s)
DNA Adducts/chemistry , Deoxyadenosines/chemistry , Epoxy Compounds/chemistry , Glycols/chemistry , Alkylation , DNA-Directed DNA Polymerase , Genes, ras , Hydrogen Bonding , Magnetic Resonance Spectroscopy , Molecular Structure , Mutagenesis, Site-Directed , Oligodeoxyribonucleotides/chemical synthesis , Poly U/chemical synthesis
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