scholarly journals Predicting transcription factor specificity with all-atom models

2008 ◽  
Vol 36 (19) ◽  
pp. 6209-6217 ◽  
Author(s):  
Sahand J. Rahi ◽  
Peter Virnau ◽  
Leonid A. Mirny ◽  
Mehran Kardar
Keyword(s):  
Transcription Factor ◽  
Computational Prediction ◽  
Systematic Evaluation ◽  
Dna Complexes ◽  
Atomistic Models ◽  
Protein Dna Interactions ◽  
Factor Specificity ◽  
Ab Initio Approach ◽  
Dna Complex ◽  
Operator Site

Abstract The binding of a transcription factor (TF) to a DNA operator site can initiate or repress the expression of a gene. Computational prediction of sites recognized by a TF has traditionally relied upon knowledge of several cognate sites, rather than an ab initio approach. Here, we examine the possibility of using structure-based energy calculations that require no knowledge of bound sites but rather start with the structure of a protein–DNA complex. We study the PurR Escherichia coli TF, and explore to which extent atomistic models of protein–DNA complexes can be used to distinguish between cognate and noncognate DNA sites. Particular emphasis is placed on systematic evaluation of this approach by comparing its performance with bioinformatic methods, by testing it against random decoys and sites of homologous TFs. We also examine a set of experimental mutations in both DNA and the protein. Using our explicit estimates of energy, we show that the specificity for PurR is dominated by direct protein–DNA interactions, and weakly influenced by bending of DNA.

scholarly journals Continuous B- to A- Transition in Protein-DNA Binding - How Well Is It Described by Current AMBER Force Fields?

2022 ◽  
Author(s):  
Petr Jurecka ◽  
Marie Zgarbova ◽  
Filip Cerny ◽  
Jan Salomon
Keyword(s):  
Force Fields ◽  
Md Simulations ◽  
Binding Motif ◽  
Dna Complexes ◽  
Continuous Transition ◽  
Correct Sequence ◽  
Protein Dna Interactions ◽  
Intermediate States ◽  
Amber Force Fields ◽  
Dna Complex

When DNA interacts with a protein, its structure often undergoes significant conformational adaptation. Perhaps the most common is the transition from canonical B-DNA towards the A-DNA form, which is not a two-state, but rather a continuous transition. The A- and B- forms differ mainly in sugar pucker P (north/south) and glycosidic torsion χ (high-anti/anti). The combination of A-like P and B-like χ (and vice versa) represents the nature of the intermediate states lying between the pure A- and B- forms. In this work, we study how the A/B equilibrium and in particular the A/B intermediate states, which are known to be over-represented at protein-DNA interfaces, are modeled by current AMBER force fields. Eight protein-DNA complexes and their naked (unbound) DNAs were simulated with OL15 and bsc1 force fields as well as an experimental combination OL15χOL3. We found that while the geometries of the A-like intermediate states in the molecular dynamics (MD) simulations agree well with the native X-ray geometries found in the protein-DNA complexes, their populations (stabilities) are significantly underestimated. Different force fields predict different propensities for A-like states growing in the order OL15 < bsc1 < OL15χOL3, but the overall populations of the A-like form are too low in all of them. Interestingly, the force fields seem to predict the correct sequence-dependent A-form propensity, as they predict larger populations of the A-like form in naked (unbound) DNA in those steps that acquire A-like conformations in protein-DNA complexes. The instability of A-like geometries in current force fields may significantly alter the geometry of the simulated protein-DNA complex, destabilize the binding motif, and reduce the binding energy, suggesting that refinement is needed to improve description of protein-DNA interactions in AMBER force fields.

scholarly journals Functional dissection of the B" component of RNA polymerase III transcription factor IIIB: a scaffolding protein with multiple roles in assembly and initiation of transcription.

1997 ◽  
Vol 17 (4) ◽  
pp. 1868-1880 ◽  
Author(s):  
A Kumar ◽  
G A Kassavetis ◽  
E P Geiduschek ◽  
M Hambalko ◽  
C J Brent
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Iii ◽  
Dna Complexes ◽  
Protein Footprinting ◽  
U6 Snrna ◽  
Polymerase Iii ◽  
Core Proteins ◽  
Transcription Factor Iiib ◽  
Dna Complex

Transcription factor IIIB (TFIIIB), the central transcription factor of Saccharomyces cerevisiae RNA polymerase III, is composed of TATA-binding protein, the TFIIB-related protein Brf, and B". B", the last component to enter the TFIIIB-DNA complex, confers extremely tight DNA binding on TFIIIB. Terminally and internally deleted B" derivatives were tested for competence to form TFIIIB-DNA complexes by TFIIIC-dependent and -independent pathways on the SUP4 tRNA(Tyr) and U6 snRNA (SNR6) genes, respectively, and for transcription. Selected TFIIIB-TFIIIC-DNA complexes assembled with truncated B" were analyzed by DNase I footprinting, and the surface topography of B" in the TFIIIB-DNA complex was also analyzed by hydroxyl radical protein footprinting. These analyses define functional domains of B" and also reveal roles in start site selection by RNA polymerase III and in clearing TFIIIC from the transcriptional start. Although absolutely required for transcription, B" can be extensively truncated. Core proteins retaining as few as 176 (of 594) amino acids remain competent to transcribe the SNR6 gene in vitro. TFIIIC-dependent assembly on DNA and transcription requires a larger core of B": two domains (I and II) that are required for SNR6 transcription on an either-or basis are simultaneously required for TFIIIC-dependent assembly of DNA complexes and transcription. Domains I and II of B" are buried upon assembly of the TFIIIB-DNA complex, as determined by protein footprinting. The picture of the TFIIIB-DNA complex that emerges is that B" serves as its scaffold and is folded over in the complex so that domains I and II are near one another.

scholarly journals Assembly of the Hap2p/Hap3p/Hap4p/Hap5p-DNA Complex in Saccharomyces cerevisiae

2005 ◽  
Vol 4 (11) ◽  
pp. 1829-1839 ◽  
Author(s):  
David S. McNabb ◽  
Inés Pinto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Dna Interactions ◽  
Activation Domain ◽  
Binding Factor ◽  
Protein Dna Interactions ◽  
Dna Complex

ABSTRACT The CCAAT-binding factor (CBF) is an evolutionarily conserved multimeric transcriptional activator in eukaryotes. In Saccharomyces cerevisiae, the CCAAT-binding factor is composed of four subunits, termed Hap2p, Hap3p, Hap4p, and Hap5p. The Hap2p/Hap3p/Hap5p heterotrimer is the DNA-binding component of the complex that binds to the consensus 5′-CCAAT-3′ sequence in the promoter of target genes. The Hap4p subunit contains the transcriptional activation domain necessary for stimulating transcription after interacting with Hap2p/Hap3p/Hap5p. In this report, we demonstrate that Hap2p, Hap3p, and Hap5p assemble via a one-step pathway requiring all three subunits simultaneously, as opposed to the mammalian CCAAT-binding factor which has been shown to assemble via a two-step pathway with CBF-A (Hap3p homolog) and CBF-C (Hap5p homolog) forming a stable dimer before CBF-B (Hap2p homolog) can interact. We have also found that the interaction of Hap4p with Hap2p/Hap3p/Hap5p requires DNA binding as a prerequisite. To further understand the protein-protein and protein-DNA interactions of this transcription factor, we identified the minimal domain of Hap4p necessary for interaction with the Hap2p/Hap3p/Hap5p-DNA complex, and we demonstrate that this domain is sufficient to complement the respiratory deficiency of a hap4Δ mutant and activate transcription when fused with the VP16 activation domain. These studies provide a further understanding of the assembly of the yeast CCAAT-binding factor at target promoters and raise a number of questions concerning the protein-protein and protein-DNA interactions of this multisubunit transcription factor.

scholarly journals Structural basis of TFIIH activation for nucleotide excision repair

2019 ◽  
Author(s):  
Goran Kokic ◽  
Aleksandar Chernev ◽  
Dimitry Tegunov ◽  
Christian Dienemann ◽  
Henning Urlaub ◽  
...  
Keyword(s):  
Dna Repair ◽  
Transcription Factor ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Lesions ◽  
Structural Basis ◽  
Disease Mutations ◽  
Mechanistic Analysis ◽  
Nucleotide Excision ◽  
Dna Complex

AbstractGenomes are constantly threatened by DNA damage, but cells can remove a large variety of DNA lesions by nucleotide excision repair (NER)1. Mutations in NER factors compromise cellular fitness and cause human diseases such as Xeroderma pigmentosum (XP), Cockayne syndrome and trichothiodystrophy2,3. The NER machinery is built around the multisubunit transcription factor IIH (TFIIH), which opens the DNA repair bubble, scans for the lesion, and coordinates excision of the damaged DNA single strand fragment1,4. TFIIH consists of a kinase module and a core module that contains the ATPases XPB and XPD5. Here we prepare recombinant human TFIIH and show that XPB and XPD are stimulated by the additional NER factors XPA and XPG, respectively. We then determine the cryo-electron microscopy structure of the human core TFIIH-XPA-DNA complex at 3.6 Å resolution. The structure represents the lesion-scanning intermediate on the NER pathway and rationalizes the distinct phenotypes of disease mutations. It reveals that XPB and XPD bind double- and single-stranded DNA, respectively, consistent with their translocase and helicase activities. XPA forms a bridge between XPB and XPD, and retains the DNA at the 5’-edge of the repair bubble. Biochemical data and comparisons with prior structures6,7 explain how XPA and XPG can switch TFIIH from a transcription factor to a DNA repair factor. During transcription, the kinase module inhibits the repair helicase XPD8. For DNA repair, XPA dramatically rearranges the core TFIIH structure, which reorients the ATPases, releases the kinase module and displaces a ‘plug’ element from the DNA-binding pore in XPD. This enables XPD to move by ~80 Å, engage with DNA, and scan for the lesion in a XPG-stimulated manner. Our results provide the basis for a detailed mechanistic analysis of the NER mechanism.

Microscopic understanding of the conformational features of a protein–DNA complex

2017 ◽  
Vol 19 (48) ◽  
pp. 32459-32472 ◽  
Author(s):  
Sandip Mondal ◽  
Kaushik Chakraborty ◽  
Sanjoy Bandyopadhyay
Keyword(s):  
Dna Interactions ◽  
P Protein ◽  
Protein Dna Interactions ◽  
Initiation Of Transcription ◽  
Dna Complex

Protein–DNA interactions play crucial roles in different stages of genetic activities, such as replication of genome, initiation of transcription,etc.

FIGalpha, a germ cell specific transcription factor involved in the coordinate expression of the zona pellucida genes

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 4939-4947 ◽  
Author(s):  
L. Liang ◽  
S.M. Soyal ◽  
J. Dean
Keyword(s):  
Transcription Factor ◽  
Zona Pellucida ◽  
Reporter Genes ◽  
Single Copy ◽  
Luciferase Reporter ◽  
Embryonic Fibroblasts ◽  
Transcription Start Sites ◽  
Helix Loop Helix ◽  
E Box ◽  
Dna Complex

The mouse zona pellucida is composed of three glycoproteins, ZP1, ZP2 and ZP3, encoded by single-copy genes whose expression is temporally and spatially restricted to oocytes. All three proteins are required for the formation of the extracellular zona matrix and female mice with a single disrupted zona gene lack a zona and are infertile. An E-box (CANNTG), located approximately 200 bp upstream of the transcription start sites of Zp1, Zp2 and Zp3, forms a protein-DNA complex present in oocytes and, to a much lesser extent, in testes. It has been previously shown that the integrity of this E-box in Zp2 and Zp3 promoters is required for expression of luciferase reporter genes microinjected into growing oocytes. The presence of the ubiquitous transcription factor E12 in the complex was used to identify a novel basic helix-loop-helix protein, FIGalpha (Factor In the Germline alpha) whose expression was limited to oocytes within the ovary. The ability of FIGalpha to transactivate reporter genes coupled to each of the three mouse zona promoters in heterologous 10T(1/2) embryonic fibroblasts suggests a role in coordinating the expression of the three zona pellucida genes during oogenesis.

Sign in / Sign up

Export Citation Format

Share Document