scholarly journals Purification and Characterization of the AAA+ Domain of Sinorhizobium meliloti DctD, a σ54-Dependent Transcriptional Activator

2004 ◽  
Vol 186 (11) ◽  
pp. 3499-3507 ◽  
Author(s):  
Hao Xu ◽  
Baohua Gu ◽  
B. Tracy Nixon ◽  
Timothy R. Hoover
Keyword(s):  
Dna Binding ◽  
Rna Polymerase ◽  
Sinorhizobium Meliloti ◽  
Atp Hydrolysis ◽  
Binding Domain ◽  
Stable Complex ◽  
Dna Binding Domain ◽  
Dna Binding Domains ◽  
Binding Domains

ABSTRACT Activators of σ54-RNA polymerase holoenzyme couple ATP hydrolysis to formation of an open complex between the promoter and RNA polymerase. These activators are modular, consisting of an N-terminal regulatory domain, a C-terminal DNA-binding domain, and a central activation domain belonging to the AAA+ superfamily of ATPases. The AAA+ domain of Sinorhizobium meliloti C4-dicarboxylic acid transport protein D (DctD) is sufficient to activate transcription. Deletion analysis of the 3′ end of dctD identified the minimal functional C-terminal boundary of the AAA+ domain of DctD as being located between Gly-381 and Ala-384. Histidine-tagged versions of the DctD AAA+ domain were purified and characterized. The DctD AAA+ domain was significantly more soluble than DctD( Δ 1-142), a truncated DctD protein consisting of the AAA+ and DNA-binding domains. In addition, the DctD AAA+ domain was more homogeneous than DctD( Δ 1-142) when analyzed by native gel electrophoresis, migrating predominantly as a single high-molecular-weight species, while DctD( Δ 1-142) displayed multiple species. The DctD AAA+ domain, but not DctD( Δ 1-142), formed a stable complex with σ54 in the presence of the ATP transition state analogue ADP-aluminum fluoride. The DctD AAA+ domain activated transcription in vitro, but many of the transcripts appeared to terminate prematurely, suggesting that the DctD AAA+ domain interfered with transcription elongation. Thus, the DNA-binding domain of DctD appears to have roles in controlling the oligomerization of the AAA+ domain and modulating interactions with σ54 in addition to its role in recognition of upstream activation sequences.

scholarly journals Characterization of the dead ringer gene identifies a novel, highly conserved family of sequence-specific DNA-binding proteins.

1996 ◽  
Vol 16 (3) ◽  
pp. 792-799 ◽  
Author(s):  
S L Gregory ◽  
R D Kortschak ◽  
B Kalionis ◽  
R Saint
Keyword(s):  
Dna Binding ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
The Dead

We reported the identification of a new family of DNA-binding proteins from our characterization of the dead ringer (dri) gene of Drosophila melanogaster. We show that dri encodes a nuclear protein that contains a sequence-specific DNA-binding domain that bears no similarity to known DNA-binding domains. A number of proteins were found to contain sequences homologous to this domain. Other proteins containing the conserved motif include yeast SWI1, two human retinoblastoma binding proteins, and other mammalian regulatory proteins. A mouse B-cell-specific regulator exhibits 75% identity with DRI over the 137-amino-acid DNA-binding domains of these proteins, indicating a high degree of conservation of this domain. Gel retardation and optimal binding site screens revealed that the in vitro sequence specificity of DRI is strikingly similar to that of many homeodomain proteins, although the sequence and predicted secondary structure do not resemble a homeodomain. The early general expression of dri and the similarity of DRI and homeodomain in vitro DNA-binding specificity compound the problem of understanding the in vivo specificity of action of these proteins. Maternally derived dri product is found throughout the embryo until germ band extension, when dri is expressed in a developmentally regulated set of tissues, including salivary gland ducts, parts of the gut, and a subset of neural cells. The discovery of this new, conserved DNA-binding domain offers an explanation for the regulatory activity of several important members of this class and predicts significant regulatory roles for the others.

scholarly journals Structure of the XPA DNA binding domain and RPA high-affinity DNA binding domains on a model NER substrate

2019 ◽  
Vol 75 (a1) ◽  
pp. a203-a203
Author(s):  
Walter J. Chazin ◽  
Agnieszka M. Topolska-Woś ◽  
Norie Sugitani ◽  
John J. Cordoba ◽  
Hyun Suk Kim ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Dna Binding Domains ◽  
High Affinity ◽  
Binding Domains

scholarly journals Specific Binding of Integrase to the Origin of Transfer (oriT) of the Conjugative Transposon Tn916

2001 ◽  
Vol 183 (9) ◽  
pp. 2947-2951 ◽  
Author(s):  
Douglas Hinerfeld ◽  
Gordon Churchward
Keyword(s):  
Dna Binding ◽  
Specific Binding ◽  
Binding Domain ◽  
Conjugal Transfer ◽  
Dna Binding Domain ◽  
Conjugative Transposon ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
A Site ◽  
Integrase Protein

ABSTRACT Purified integrase protein (Int) of the conjugative transposon Tn916 was shown, using nuclease protection experiments, to bind specifically to a site within the origin of conjugal transfer of the transposon, oriT. A sequence similar to the ends of the transposon that are bound by the C-terminal DNA-binding domain of Int was present in the protected region. However, Int binding tooriT required both the N- and C-terminal DNA-binding domains of Int, and the pattern of nuclease protection differed from that observed when Int binds to the transposon ends and flanking DNA. Binding of Int to oriT may be part of a mechanism to prevent premature conjugal transfer of Tn916 prior to excision from the donor DNA.

scholarly journals B-Cell Coactivator OBF-1 Exhibits Unusual Transcriptional Properties and Functions in a DNA-Bound Oct-1-Dependent Fashion

1999 ◽  
Vol 19 (6) ◽  
pp. 4247-4254 ◽  
Author(s):  
Andrea Krapp ◽  
Michel Strubin
Keyword(s):  
Dna Binding ◽  
B Cell ◽  
Target Genes ◽  
Regulatory Elements ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Activation Domain ◽  
Activation Domains ◽  
Dna Binding Domains ◽  
Binding Domains

ABSTRACT Eukaryotic transcriptional activators generally comprise both a DNA-binding domain that recognizes specific cis-regulatory elements in the target genes and an activation domain which is essential for transcriptional stimulation. Activation domains typically behave as structurally and functionally autonomous modules that retain their intrinsic activities when directed to a promoter by a variety of heterologous DNA-binding domains. Here we report that OBF-1, a B-cell-specific coactivator for transcription factor Oct-1, challenges this traditional view in that it contains an atypical activation domain that exhibits two unexpected functional properties when tested in the yeast Saccharomyces cerevisiae. First, OBF-1 by itself has essentially no intrinsic activation potential, yet it strongly synergizes with other activation domains such as VP16 and Gal4. Second, OBF-1 exerts its effect in association with DNA-bound Oct-1 but is inactive when attached to a heterologous DNA-binding domain. These findings suggest that activation by OBF-1 is not obtained by simple recruitment of the coactivator to the promoter but requires interaction with DNA-bound Oct-1 to stimulate a step distinct from those regulated by classical activation domains.

scholarly journals Expression and purification of 6xHis-tagged DNA binding domains of functional ecdysteroid receptor from drosophila melanogaster.

1996 ◽  
Vol 43 (4) ◽  
pp. 611-621 ◽  
Author(s):  
A Rusin ◽  
A Niedziela-Majka ◽  
G Rymarczyk ◽  
A Ozyhar
Keyword(s):  
Dna Binding ◽  
Dna Interaction ◽  
Binding Domain ◽  
Structural Basis ◽  
Dna Binding Domain ◽  
Affinity Tag ◽  
Mobility Shift ◽  
Ecdysteroid Receptor ◽  
Dna Binding Domains ◽  
Binding Domains

Two members of the nuclear receptor superfamily, EcR and Ultraspiracle (Usp) heterodimerize to form a functional receptor for 20-hydroxyecdysone-the key ecdysteroid controlling induction and modulation of morphogenetic events through Drosophila development. In order to study aspects of receptor function and ultimately the structural basis of the ecdysteroid receptor-DNA interaction, it is necessary to produce large quantities of purified EcR and Usp DNA-binding domains. Toward this end, we have expressed the EcR DNA-binding domain and the Usp DNA-binding domain as proteins with an affinity tag consisting of six histidine residues (6xHis-EcRDBD and 6xHis-UspDBD, respectively) using the expression vector pQE-30. Under optimal conditions, elaborated in this study, bacteria can express the recombinant 6xHis-EcRDBD to the levels of 11% of total soluble proteins and the 6xHis-UspDBD to the levels of 16%. Both proteins were purified to homogeneity from the soluble protein fraction using combination of ammonium sulphate fractionation and affinity chromatography on Ni-NTA agarose. The gel mobility shift experiments demonstrated that the purified 6xHis-EcRDBD and the 6xHis-UspDBD interact specifically with an 20-hydroxyecdysone response element from the promoter region of the hsp 27 Drosophila gene.

scholarly journals Differential abilities to engage inaccessible chromatin diversify vertebrate HOX binding patterns

2019 ◽  
Author(s):  
Milica Bulajić ◽  
Divyanshi Srivastava ◽  
Jeremy S Dasen ◽  
Hynek Wichterle ◽  
Shaun Mahony ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Dna Binding Domain ◽  
Regulatory Activity ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Posterior Group ◽  
Differential Gene ◽  
Domain Similarity

ABSTRACTWhile Hox genes encode for conserved transcription factors (TFs), they are further divided into anterior, central, and posterior groups based on their DNA-binding domain similarity. The posterior Hox group expanded in the deuterostome clade and patterns caudal and distal structures. We aim to address how similar HOX TFs diverge to induce different positional identities. We studied HOX TF DNA-binding and regulatory activity during an in vitro motor neuron differentiation system that recapitulates embryonic development. We find diversity in the genomic binding profiles of different HOX TFs, even among the posterior group paralogs that share similar DNA binding domains. These differences in genomic binding are explained by differing abilities to bind to previously inaccessible sites. For example, the posterior group HOXC9 has a greater ability to bind occluded sites than the posterior HOXC10, producing different binding patterns and driving differential gene expression programs. From these results, we propose that the differential abilities of posterior HOX TFs to bind to previously inaccessible chromatin drive patterning diversification.

scholarly journals Adf-1 Is a Nonmodular Transcription Factor That Contains a TAF-Binding Myb-Like Motif

1998 ◽  
Vol 18 (4) ◽  
pp. 2252-2261 ◽  
Author(s):  
Gene Cutler ◽  
Kathleen M. Perry ◽  
Robert Tjian
Keyword(s):  
Dna Binding ◽  
Gene Activation ◽  
Point Mutations ◽  
Binding Domain ◽  
Intact Protein ◽  
Dna Binding Domain ◽  
Unusual Structure ◽  
Dna Binding Domains ◽  
Binding Domains

ABSTRACT Adf-1 is an essential Drosophila melanogastersequence-specific transactivator that binds the promoters of a diverse group of genes. We have performed a comprehensive mapping of the functional domains of Adf-1 to study the role of transactivators in the process of gene activation. Using a series of clustered point mutations and small deletions we have identified regions of Adf-1 required for DNA binding, dimerization, and activation. In contrast to most enhancer-binding factors, the Adf-1 activation regions are nonmodular and depend on an intact protein, including the Adf-1 DNA-binding domain, for activity. Like many transcriptional activators, Adf-1 contains a TFIID-binding domain that can interact with specific TAF subunits. Although TAFs are required for Adf-1-directed activation, TAF binding is not sufficient, suggesting that Adf-1 may direct multiple essential steps during activation. Interestingly, both the TAF-binding domain and the DNA-binding domain contain sequences homologous to those of the Myb family of DNA-binding domains. Thus, Adf-1 has evolved an unusual structure containing two versions of the Myb motif, one that binds DNA and one that binds proteins.

Heteronuclear Strategies for the Assignment of Larger protein/DNA complexes: Application to the 37 kDa trp Represser-Operator Complex

1997 ◽  
Author(s):  
M.J. Revington ◽  
W. Lee
Keyword(s):  
Dna Binding ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Nmr Studies ◽  
Dna Complexes ◽  
Dna Binding Domains ◽  
Binding Domains

The sequence-specific DNA binding function of many proteins is recognized as one of the central mechanisms of regulating transcription and DNA replication and repair. The ability of these proteins to select a short (usually 10 to 20 basepair) sequence out of the entire genome with which to form a stable complex is a prime example of molecular recognition. Atomic resolution structural studies using NMR and X-ray crystallography have emerged as essential techniques in understanding the basis of specificity and stability in these systems. While NMR studies of small DNA-binding domains of proteins have become almost routine (see Kaptein, 1993 for a review) relatively few NMR studies of protein-DNA complexes have been reported. These include the lac repressor headpiece complex (Chuprina et al., 1993). the Antennapedia homeodomain complex (Billetere et al., 1993), the GATA-1 complex (Omichinski et al., 1993). and the Myb DNA binding domain complex (Ogata et al., 1993); all of these complexes are smaller than 20 kDa. In most cases, size limitations have meant that only the DNA binding domain of the protein in complex with a single binding element have been studied. In vivo, however, most DNA binding proteins are much larger than these domains and often function as oligomers. The decrease in quality and increase in complexity of spectra as the molecular weight of the sample increases, limits the number of systems amenable to study using NMR and influences the decision to focus on single domains of multidomain proteins. However, since many DNA-binding proteins are regulated by the binding of ligands, other proteins or phosphorylation, often at sites distal from the DNA-binding domain, it is preferable to study as much of the intact protein as possible in order to characterize allosteric and regulatory mechanisms (Pabo and Sauer, 1992). E. coli trp repressor is a 25 kDa homodimer that regulates operons involved in tryptophan biosynthesis. The dimer is one of the smallest intact proteins that binds sequence specifically to DNA and whose affinity is modulated by an effector (L-tryptophan).

scholarly journals Computational studies on the identification and analyses of p53 cancer associated mutations

2017 ◽  
Author(s):  
◽  
Nosipho Magnificat Cele
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Dna Binding ◽  
Hydrogen Bonds ◽  
Human Cancer ◽  
Md Simulations ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Dna Binding Domains ◽  
Binding Domains

P53 is a tumour suppressor protein that is dysfunctional in most human cancer cells. Mutations in the p53 genes result in the expression of mutant proteins which accumulate to high levels in tumour cells. Several studies have shown that majority of the mutations are concentrated in the DNA-binding domain where they destabilize its conformation and eliminate the sequence- specific DNA-binding to abolish p53 transcription activities. Accordingly, this study involved an investigation of the effects of mutations associated with cancer, based on the framework of sequences and structures of p53 DNA-binding domains, analysed by SIFT, Pmut, I-mutant, MuStab, CUPSAT, EASY-MM and SDM servers. These analyses suggest that 156 mutations may be associated with cancer, and may result in protein malfunction, including the experimentally validated mutations. Thereafter, 54 mutations were further classified as disease- causing mutations and probably have a significant impact on the stability of the structure. The detailed stability analyses revealed that Val143Asp, Ala159Pro, Val197Pro, Tyr234Pro, Cys238Pro, Gly262Pro and Cys275Pro mutations caused the highest destabilization of the structure thus leading to malfunctioning of the protein. Additionally, the structural and functional consequences of the resulting highly destabilizing mutations were explored further using molecular docking and molecular dynamics simulations. Molecular docking results revealed that the p53 DNA-binding domain loses its stability and abrogates the specific DNA-binding as shown by a decrease in binding affinity characterized by the ZRANK scores. This result was confirmed by the residues Val143Asp, Ala159Pro, Val197Pro, Tyr234Pro and Cys238Pro p53-DNA mutant complexes inducing the loss of important hydrogen bonds, and introduced non-native hydrogen bonds between the two biomolecules. Furthermore, Molecular dynamics (MD) simulations of the experimental mutant forms showed that the structures of the p53 DNA-binding domains were more rigid comparing to the wild-type structure. The MD trajectories of Val134Ala, Arg213Gly and Gly245Ser DNA-binding domain mutants clearly revealed a loss of the flexibility and stability by the structures. This might affect the structural conformation and interfere with the interaction to DNA. Understanding the effects of mutations associated with cancer at a molecular level will be helpful in designing new therapeutics for cancer diseases.

scholarly journals Role of Papillomavirus E1 Initiator Dimerization in DNA Replication

2005 ◽  
Vol 79 (13) ◽  
pp. 8661-8664 ◽  
Author(s):  
Stephen Schuck ◽  
Arne Stenlund
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Severe Effect ◽  
Origin Of Dna Replication ◽  
Initiation Of Dna Replication

ABSTRACT Viral initiator proteins are polypeptides that form oligomeric complexes on the origin of DNA replication (ori). These complexes carry out a multitude of functions related to initiation of DNA replication, and although many of these functions have been characterized biochemically, little is understood about how the complexes are assembled. Here we demonstrate that loss of one particular interaction, the dimerization between E1 DNA binding domains, has a severe effect on DNA replication in vivo but has surprisingly modest effects on most individual biochemical activities in vitro. We conclude that the dimer interaction is primarily required for initial recognition of ori.

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