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  1. Article ; Online: X-ray Structure Characterization of the Selective Recognition of AT Base Pair Sequences.

    Ogbonna, Edwin N / Paul, Ananya / Farahat, Abdelbasset A / Terrell, J Ross / Mineva, Ekaterina / Ogbonna, Victor / Boykin, David W / Wilson, W David

    ACS bio & med chem Au

    2023  Volume 3, Issue 4, Page(s) 335–348

    Abstract: The rational design of small molecules that target specific DNA sequences is a promising strategy to modulate gene expression. This report focuses on a diamidinobenzimidazole compound, whose selective binding to the minor groove of AT DNA sequences holds ...

    Abstract The rational design of small molecules that target specific DNA sequences is a promising strategy to modulate gene expression. This report focuses on a diamidinobenzimidazole compound, whose selective binding to the minor groove of AT DNA sequences holds broad significance in the molecular recognition of AT-rich human promoter sequences. The objective of this study is to provide a more detailed and systematized understanding, at an atomic level, of the molecular recognition mechanism of different AT-specific sequences by a rationally designed minor groove binder. The specialized method of X-ray crystallography was utilized to investigate how the sequence-dependent recognition properties in general, A-tract, and alternating AT sequences affect the binding of diamidinobenzimidazole in the DNA minor groove. While general and A-tract AT sequences give a narrower minor groove, the alternating AT sequences intrinsically have a wider minor groove which typically constricts upon binding. A strong and direct hydrogen bond between the N-H of the benzimidazole and an H-bond acceptor atom in the minor groove is essential for DNA recognition in all sequences described. In addition, the diamidine compound specifically utilizes an interfacial water molecule for its DNA binding. DNA complexes of AATT and AAAAAA recognition sites show that the diamidine compound can bind in two possible orientations with a preference for water-assisted hydrogen bonding at either cationic end. The complex structures of AAATTT, ATAT, ATATAT, and AAAA are bound in a singular orientation. Analysis of the helical parameters shows a minor groove expansion of about 1 Å across all the nonalternating DNA complexes. The results from this systematic approach will convey a greater understanding of the specific recognition of a diverse array of AT-rich sequences by small molecules and more insight into the design of small molecules with enhanced specificity to AT and mixed DNA sequences.
    Language English
    Publishing date 2023-04-05
    Publishing country United States
    Document type Journal Article
    ISSN 2694-2437
    ISSN (online) 2694-2437
    DOI 10.1021/acsbiomedchemau.3c00002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Dissection of integrated readout reveals the structural thermodynamics of DNA selection by transcription factors.

    Vernon, Tyler N / Terrell, J Ross / Albrecht, Amanda V / Germann, Markus W / Wilson, W David / Poon, Gregory M K

    Structure (London, England : 1993)

    2023  Volume 32, Issue 1, Page(s) 83–96.e4

    Abstract: Nucleobases such as inosine have been extensively utilized to map direct contacts by proteins in the DNA groove. Their deployment as targeted probes of dynamics and hydration, which are dominant thermodynamic drivers of affinity and specificity, has been ...

    Abstract Nucleobases such as inosine have been extensively utilized to map direct contacts by proteins in the DNA groove. Their deployment as targeted probes of dynamics and hydration, which are dominant thermodynamic drivers of affinity and specificity, has been limited by a paucity of suitable experimental models. We report a joint crystallographic, thermodynamic, and computational study of the bidentate complex of the arginine side chain with a Watson-Crick guanine (Arg×GC), a highly specific configuration adopted by major transcription factors throughout the eukaryotic branches in the Tree of Life. Using the ETS-family factor PU.1 as a high-resolution structural framework, inosine substitution for guanine resulted in a sharp dissection of conformational dynamics and hydration and elucidated their role in the DNA specificity of PU.1. Our work suggests an under-exploited utility of modified nucleobases in untangling the structural thermodynamics of interactions, such as the Arg×GC motif, where direct and indirect readout are tightly integrated.
    MeSH term(s) Transcription Factors/metabolism ; Binding Sites ; Protein Binding ; Proto-Oncogene Proteins/chemistry ; Thermodynamics ; DNA/metabolism ; Guanine ; Inosine/metabolism ; Nucleic Acid Conformation
    Chemical Substances Transcription Factors ; Proto-Oncogene Proteins ; DNA (9007-49-2) ; Guanine (5Z93L87A1R) ; Inosine (5A614L51CT)
    Language English
    Publishing date 2023-12-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1213087-4
    ISSN 1878-4186 ; 0969-2126
    ISSN (online) 1878-4186
    ISSN 0969-2126
    DOI 10.1016/j.str.2023.11.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: DNA selection by the master transcription factor PU.1.

    Terrell, J Ross / Taylor, Samuel J / Schneider, Amelia L / Lu, Yue / Vernon, Tyler N / Xhani, Suela / Gumpper, Ryan H / Luo, Ming / Wilson, W David / Steidl, Ulrich / Poon, Gregory M K

    Cell reports

    2023  Volume 42, Issue 7, Page(s) 112671

    Abstract: The master transcriptional regulator PU.1/Spi-1 engages DNA sites with affinities spanning multiple orders of magnitude. To elucidate this remarkable plasticity, we have characterized 22 high-resolution co-crystallographic PU.1/DNA complexes across the ... ...

    Abstract The master transcriptional regulator PU.1/Spi-1 engages DNA sites with affinities spanning multiple orders of magnitude. To elucidate this remarkable plasticity, we have characterized 22 high-resolution co-crystallographic PU.1/DNA complexes across the addressable affinity range in myeloid gene transactivation. Over a purine-rich core (such as 5'-GGAA-3') flanked by variable sequences, affinity is negotiated by direct readout on the 5' flank via a critical glutamine (Q226) sidechain and by indirect readout on the 3' flank by sequence-dependent helical flexibility. Direct readout by Q226 dynamically specifies PU.1's characteristic preference for purines and explains the pathogenic mutation Q226E in Waldenström macroglobulinemia. The structures also reveal how disruption of Q226 mediates strand-specific inhibition by DNA methylation and the recognition of non-canonical sites, including the authentic binding sequence at the CD11b promoter. A re-synthesis of phylogenetic and structural data on the ETS family, considering the centrality of Q226 in PU.1, unifies the model of DNA selection by ETS proteins.
    MeSH term(s) Phylogeny ; Binding Sites ; Trans-Activators/metabolism ; DNA/metabolism
    Chemical Substances proto-oncogene protein Spi-1 ; Trans-Activators ; DNA (9007-49-2)
    Language English
    Publishing date 2023-06-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, Non-U.S. Gov't
    ZDB-ID 2649101-1
    ISSN 2211-1247 ; 2211-1247
    ISSN (online) 2211-1247
    ISSN 2211-1247
    DOI 10.1016/j.celrep.2023.112671
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: The functions of key residues in the inhibitor, substrate and cofactor sites of human 3beta-hydroxysteroid dehydrogenase type 1 are validated by mutagenesis.

    Thomas, James L / Mack, Vance L / Sun, Jingping / Terrell, J Ross / Bucholtz, Kevin M

    The Journal of steroid biochemistry and molecular biology

    2010  Volume 120, Issue 4-5, Page(s) 192–199

    Abstract: In postmenopausal women, human 3beta-hydroxysteroid dehydrogenase type 1 (3beta-HSD1) is a critical enzyme in the conversion of DHEA to estradiol in breast tumors, while 3beta-HSD2 participates in the production of cortisol and aldosterone in the human ... ...

    Abstract In postmenopausal women, human 3beta-hydroxysteroid dehydrogenase type 1 (3beta-HSD1) is a critical enzyme in the conversion of DHEA to estradiol in breast tumors, while 3beta-HSD2 participates in the production of cortisol and aldosterone in the human adrenal gland. The goals of this project are to determine if Arg195 in 3beta-HSD1 vs. Pro195 in 3beta-HSD2 in the substrate/inhibitor binding site is a critical structural difference responsible for the higher affinity of 3beta-HSD1 for inhibitor and substrate steroids compared to 3beta-HSD2 and whether Asp61, Glu192 and Thr8 are fingerprint residues for cofactor and substrate binding using site-directed mutagenesis. The R195P-1 mutant of 3beta-HSD1 and the P195R-2 mutant of 3beta-HSD2 have been created, expressed, purified and characterized kinetically. Dixon analyses of the inhibition of the R195P-1 mutant, P195R-2 mutant, wild-type 3beta-HSD1 and wild-type 3beta-HSD2 by trilostane has produced kinetic profiles that show inhibition of 3beta-HSD1 by trilostane (K(i)=0.10microM, competitive) with a 16-fold lower K(i) and different mode than measured for 3beta-HSD2 (K(i)=1.60microM, noncompetitive). The R195P-1 mutation shifts the high-affinity, competitive inhibition profile of 3beta-HSD1 to a low-affinity (trilostane K(i)=2.56microM), noncompetitive inhibition profile similar to that of 3beta-HSD2 containing Pro195. The P195R-2 mutation shifts the low-affinity, noncompetitive inhibition profile of 3beta-HSD2 to a high-affinity (trilostane K(i)=0.19microM), competitive inhibition profile similar to that of 3beta-HSD1 containing Arg195. Michaelis-Menten kinetics for DHEA, 16beta-hydroxy-DHEA and 16alpha-hydroxy-DHEA substrate utilization by the R195P-1 and P195R-2 enzymes provide further validation for higher affinity binding due to Arg195 in 3beta-HSD1. Comparisons of the Michaelis-Menten values of cofactor and substrate for the targeted mutants of 3beta-HSD1 (D61N, D61V, E192A, T8A) clarify the functions of these residues as well.
    MeSH term(s) 3-Hydroxysteroid Dehydrogenases/antagonists & inhibitors ; 3-Hydroxysteroid Dehydrogenases/chemistry ; 3-Hydroxysteroid Dehydrogenases/genetics ; 3-Hydroxysteroid Dehydrogenases/metabolism ; Amino Acids/chemistry ; Amino Acids/genetics ; Amino Acids/metabolism ; Binding Sites ; Breast Neoplasms/drug therapy ; Dehydroepiandrosterone/chemistry ; Dehydroepiandrosterone/metabolism ; Dihydrotestosterone/analogs & derivatives ; Dihydrotestosterone/chemistry ; Dihydrotestosterone/metabolism ; Female ; Humans ; Kinetics ; Models, Molecular ; Mutagenesis, Site-Directed ; Protein Binding ; Protein Conformation ; Substrate Specificity
    Chemical Substances Amino Acids ; Dihydrotestosterone (08J2K08A3Y) ; Dehydroepiandrosterone (459AG36T1B) ; 3-Hydroxysteroid Dehydrogenases (EC 1.1.-) ; trilostane (L0FPV48Q5R)
    Language English
    Publishing date 2010-04-24
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1049188-0
    ISSN 1879-1220 ; 0960-0760
    ISSN (online) 1879-1220
    ISSN 0960-0760
    DOI 10.1016/j.jsbmb.2010.04.015
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Structure/function of the inhibition of human 3beta-hydroxysteroid dehydrogenase type 1 and type 2 by trilostane.

    Thomas, James L / Mack, Vance L / Glow, Jason A / Moshkelani, Delaram / Terrell, J Ross / Bucholtz, Kevin M

    The Journal of steroid biochemistry and molecular biology

    2008  Volume 111, Issue 1-2, Page(s) 66–73

    Abstract: The human type 1 (placenta, breast tumors) and type 2 (gonads, adrenals) isoforms of 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD) are key enzymes in biosynthesis of all active steroid hormones. Human 3beta-HSD1 is a critical enzyme in the ... ...

    Abstract The human type 1 (placenta, breast tumors) and type 2 (gonads, adrenals) isoforms of 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD) are key enzymes in biosynthesis of all active steroid hormones. Human 3beta-HSD1 is a critical enzyme in the conversion of DHEA to estradiol in breast tumors and may be a major target enzyme for the treatment of breast cancer. 3beta-HSD2 participates in the production of cortisol and aldosterone in the human adrenal gland. The goals of this project are to evaluate the role of the 2alpha-cyano group on trilostane (2alpha-cyano-4alpha,5alpha-epoxy-17beta-ol-androstane-3-one) and determine which amino acids may be critical for 3beta-HSD1 specificity. Trilostane without the 2alpha-cyano group, 4alpha,5alpha-epoxy-testosterone, was synthesized. Using our structural model of 3beta-HSD1, trilostane or 4alpha,5alpha-epoxy-testosterone was docked in the active site using Autodock 3.0, and the potentially critical residues (Met187 and Ser124) were identified. The M187T and S124T mutants of 3beta-HSD1 were created, expressed and purified. Dixon analyses of the inhibition of wild-type 3beta-HSD1, 3beta-HSD2, M187T and S124T by trilostane and 4alpha,5alpha-epoxy-testosterone suggest that the 2alpha-cyano group of trilostane is anchored by Ser124 in both isoenzymes. Kinetic analyses of cofactor and substrate utilization as well as the inhibition kinetics of M187T and the wild-type enzymes suggest that the 16-fold higher-affinity inhibition of 3beta-HSD1 by trilostane may be related to the presence of Met187 in 3beta-HSD1 and Thr187 in 3beta-HSD2. This structure/function information may lead to the production of more highly specific inhibitors of 3beta-HSD1 to block the hormone-dependent growth of breast tumors.
    MeSH term(s) 3-Hydroxysteroid Dehydrogenases/antagonists & inhibitors ; 3-Hydroxysteroid Dehydrogenases/chemistry ; 3-Hydroxysteroid Dehydrogenases/genetics ; 3-Hydroxysteroid Dehydrogenases/isolation & purification ; Amino Acid Sequence ; Amino Acid Substitution ; Binding Sites ; Dihydrotestosterone/analogs & derivatives ; Dihydrotestosterone/pharmacology ; Dose-Response Relationship, Drug ; Humans ; Isoenzymes/antagonists & inhibitors ; Isoenzymes/chemistry ; Isoenzymes/genetics ; Kinetics ; Methionine/metabolism ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Protein Binding ; Steroid Isomerases/antagonists & inhibitors ; Steroid Isomerases/chemistry ; Steroid Isomerases/genetics ; Structure-Activity Relationship ; Substrate Specificity ; Testosterone/analogs & derivatives ; Testosterone/pharmacology ; Threonine/metabolism
    Chemical Substances Isoenzymes ; Dihydrotestosterone (08J2K08A3Y) ; Threonine (2ZD004190S) ; Testosterone (3XMK78S47O) ; Methionine (AE28F7PNPL) ; 3-Hydroxysteroid Dehydrogenases (EC 1.1.-) ; Steroid Isomerases (EC 5.3.3.-) ; trilostane (L0FPV48Q5R)
    Language English
    Publishing date 2008-05-03
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1049188-0
    ISSN 1879-1220 ; 0960-0760
    ISSN (online) 1879-1220
    ISSN 0960-0760
    DOI 10.1016/j.jsbmb.2008.04.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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