scholarly journals Expression, purification and crystal structure determination of a ferredoxin reductase from the actinobacterium Thermobifida fusca

2020 ◽  
Author(s):  
Jhon Alexander Rodriguez Buitrago ◽  
Thomas Klünemann ◽  
Wulf Blankenfeldt ◽  
Anett Schallmey

AbstractFerredoxin reductase FdR9 from Thermobifida fusca, a member of the oxygenase-coupled NADH-dependent ferredoxin reductase (FNR) family, catalyzes electron transfer from NADH to its physiological electron acceptor ferredoxin. It forms part of a three-component cytochrome P450 monooxygenase system in T. fusca. Here, FdR9 was overexpressed and purified and its crystal structure was determined at 1.8 Å resolution. The overall structure of FdR9 is similar to other members of the FNR family and is composed of an FAD-binding domain, an NAD-binding domain and a C-terminal domain. Activity measurements with FdR9 confirmed a strong preference for NADH as the cofactor. Comparison of the FAD- and NAD-binding domains of FdR9 with other ferredoxin reductases revealed the presence of conserved sequence motifs in the FAD-binding domain as well as several highly conserved residues involved in FAD and NAD cofactor binding. Moreover, the NAD-binding site of FdR9 contains a modified Rossmann fold motif, GxSxxS, instead of the classical GxGxxG motif.

Author(s):  
Jhon Alexander Rodriguez Buitrago ◽  
Thomas Klünemann ◽  
Wulf Blankenfeldt ◽  
Anett Schallmey

The ferredoxin reductase FdR9 from Thermobifida fusca, a member of the oxygenase-coupled NADH-dependent ferredoxin reductase (FNR) family, catalyses electron transfer from NADH to its physiological electron acceptor ferredoxin. It forms part of a putative three-component cytochrome P450 monooxygenase system in T. fusca comprising CYP222A1 and the [3Fe–4S]-cluster ferredoxin Fdx8 as well as FdR9. Here, FdR9 was overexpressed and purified and its crystal structure was determined at 1.9 Å resolution. The overall structure of FdR9 is similar to those of other members of the FNR family and is composed of an FAD-binding domain, an NAD-binding domain and a C-terminal domain. Activity measurements with FdR9 confirmed a strong preference for NADH as the cofactor. Comparison of the FAD- and NAD-binding domains of FdR9 with those of other ferredoxin reductases revealed the presence of conserved sequence motifs in the FAD-binding domain as well as several highly conserved residues involved in FAD and NAD cofactor binding. Moreover, the NAD-binding site of FdR9 contains a modified Rossmann-fold motif, GxSxxS, instead of the classical GxGxxG motif.


2015 ◽  
Vol 71 (12) ◽  
pp. 2505-2512 ◽  
Author(s):  
Magdalena Schacherl ◽  
Angelika A. M. Montada ◽  
Elena Brunstein ◽  
Ulrich Baumann

The U32 family is a collection of over 2500 annotated peptidases in the MEROPS database with unknown catalytic mechanism. They mainly occur in bacteria and archaea, but a few representatives have also been identified in eukarya. Many of the U32 members have been linked to pathogenicity, such as proteins fromHelicobacterandSalmonella. The first crystal structure analysis of a U32 catalytic domain fromMethanopyrus kandleri(genemk0906) reveals a modified (βα)8TIM-barrel fold with some unique features. The connecting segment between strands β7 and β8 is extended and helix α7 is located on top of the C-terminal end of the barrel body. The protein exhibits a dimeric quaternary structure in which a zinc ion is symmetrically bound by histidine and cysteine side chains from both monomers. These residues reside in conserved sequence motifs. No typical proteolytic motifs are discernible in the three-dimensional structure, and biochemical assays failed to demonstrate proteolytic activity. A tunnel in which an acetate ion is bound is located in the C-terminal part of the β-barrel. Two hydrophobic grooves lead to a tunnel at the C-terminal end of the barrel in which an acetate ion is bound. One of the grooves binds to aStrep-Tag II of another dimer in the crystal lattice. Thus, these grooves may be binding sites for hydrophobic peptides or other ligands.


2005 ◽  
Vol 71 (12) ◽  
pp. 8024-8030 ◽  
Author(s):  
Miho Sasaki ◽  
Ayako Akahira ◽  
Ko-ichi Oshiman ◽  
Tetsuaki Tsuchido ◽  
Yoshinobu Matsumura

ABSTRACT In a previous study (M. Sasaki, J. Maki, K. Oshiman, Y. Matsumura, and T. Tsuchido, Biodegradation 16:449-459, 2005), the cytochrome P450 monooxygenase system was shown to be involved in bisphenol A (BPA) degradation by Sphingomonas sp. strain AO1. In the present investigation, we purified the components of this monooxygenase, cytochrome P450 (P450bisd), ferredoxin (Fdbisd), and ferredoxin reductase (Redbisd). We demonstrated that P450bisd and Fdbisd are homodimeric proteins with molecular masses of 102.3 and 19.1 kDa, respectively, by gel filtration chromatography analysis. Spectroscopic analysis of Fdbisd revealed the presence of a putidaredoxin-type [2Fe-2S] cluster. P450bisd, in the presence of Fdbisd, Redbisd, and NADH, was able to convert BPA. The Km and k cat values for BPA degradation were 85 ± 4.7 μM and 3.9 ± 0.04 min−1, respectively. NADPH, spinach ferredoxin, and spinach ferredoxin reductase resulted in weak monooxygenase activity. These results indicated that the electron transport system of P450bisd might exhibit strict specificity. Two BPA degradation products of the P450bisd system were detected by high-performance liquid chromatography analysis and were thought to be 1,2-bis(4-hydroxyphenyl)-2-propanol and 2,2-bis(4-hydroxyphenyl)-1-propanol based on mass spectrometry-mass spectrometry analysis. This is the first report demonstrating that the cytochrome P450 monooxygenase system in bacteria is involved in BPA degradation.


2013 ◽  
Vol 41 (4) ◽  
pp. 889-895 ◽  
Author(s):  
Evelyn Sauer ◽  
Stefan Imseng ◽  
Timm Maier ◽  
Michael N. Hall

The atypical serine/threonine kinase mTOR (mammalian target of rapamycin) is a central regulator of cell growth and metabolism. mTOR is part of two multisubunit signalling complexes, mTORC1 and mTORC2. Although many aspects of mTOR signalling are understood, the lack of high-resolution structures impairs a detailed understanding of complex assembly, function and regulation. The structure of the kinase domain is of special interest for the development of mTOR inhibitors as anti-cancer agents. A homology model of the mTOR kinase domain was derived from the structure of PI3Ks (phosphoinositide 3-kinases). More recently, the crystal structure of the catalytic domain of human mTOR was determined, providing long-awaited structural insight into the architecture of mTOR. Interestingly, the homology model predicted several aspects of the crystal structure. In the present paper, we revisit the homology model in the context of the now available crystal structure of the mTOR kinase domain.


2014 ◽  
Vol 70 (a1) ◽  
pp. C825-C825
Author(s):  
Sang Jae Lee ◽  
Chao Ma ◽  
Bong-Jin Lee ◽  
Se Won Suh

The PhoU protein in bacteria plays a role in maintaining phosphate homeostasis by regulating the Pho regulon. Recent studies showed that PhoU is essential for normal growth and is also involved in persister formation. PhoU is a potential target for overcoming drug tolerance of pathogenic bacteria. However, the exact mechanism of PhoU functions is still unknown. Here we have determined the crystal structure of PhoU from Pseudomonas aeruginosa at 2.28 Å resolution by Se SAD method. P. aeruginosa PhoU exists as a dimer in the crystals. A monomer of P. aeruginosa PhoU consists of six alpha-helices, which form two similar helical bundles. P. aeruginosa PhoU shares four conserved sequence motifs. Interestingly, P. aeruginosa PhoU has distinct features in some loops and the surface charge distribution. Two monomers of P. aeruginosa PhoU dimerize in a slightly different manner to those of other PhoU proteins. The present structure of PhoU from a bacterial pathogen may be useful for the antibacterial drug discovery.


Author(s):  
Yanrong Ji ◽  
Zhihan Zhou ◽  
Han Liu ◽  
Ramana V Davuluri

Abstract Motivation Deciphering the language of non-coding DNA is one of the fundamental problems in genome research. Gene regulatory code is highly complex due to the existence of polysemy and distant semantic relationship, which previous informatics methods often fail to capture especially in data-scarce scenarios. Results To address this challenge, we developed a novel pre-trained bidirectional encoder representation, named DNABERT, to capture global and transferrable understanding of genomic DNA sequences based on up and downstream nucleotide contexts. We compared DNABERT to the most widely used programs for genome-wide regulatory elements prediction and demonstrate its ease of use, accuracy and efficiency. We show that the single pre-trained transformers model can simultaneously achieve state-of-the-art performance on prediction of promoters, splice sites and transcription factor binding sites, after easy fine-tuning using small task-specific labeled data. Further, DNABERT enables direct visualization of nucleotide-level importance and semantic relationship within input sequences for better interpretability and accurate identification of conserved sequence motifs and functional genetic variant candidates. Finally, we demonstrate that pre-trained DNABERT with human genome can even be readily applied to other organisms with exceptional performance. We anticipate that the pre-trained DNABERT model can be fined tuned to many other sequence analyses tasks. Availability and implementation The source code, pretrained and finetuned model for DNABERT are available at GitHub (https://github.com/jerryji1993/DNABERT). Supplementary information Supplementary data are available at Bioinformatics online.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ami Shah ◽  
Madison Ratkowski ◽  
Alessandro Rosa ◽  
Paul Feinstein ◽  
Thomas Bozza

AbstractOlfactory sensory neurons express a large family of odorant receptors (ORs) and a small family of trace amine-associated receptors (TAARs). While both families are subject to so-called singular expression (expression of one allele of one gene), the mechanisms underlying TAAR gene choice remain obscure. Here, we report the identification of two conserved sequence elements in the mouse TAAR cluster (T-elements) that are required for TAAR gene expression. We observed that cell-type-specific expression of a TAAR-derived transgene required either T-element. Moreover, deleting either element reduced or abolished expression of a subset of TAAR genes, while deleting both elements abolished olfactory expression of all TAARs in cis with the mutation. The T-elements exhibit several features of known OR enhancers but also contain highly conserved, unique sequence motifs. Our data demonstrate that TAAR gene expression requires two cooperative cis-acting enhancers and suggest that ORs and TAARs share similar mechanisms of singular expression.


Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1039-1044 ◽  
Author(s):  
I J Fijalkowska ◽  
R M Schaaper

Abstract The dnaE gene of Escherichia coli encodes the DNA polymerase (alpha subunit) of the main replicative enzyme, DNA polymerase III holoenzyme. We have previously identified this gene as the site of a series of seven antimutator mutations that specifically decrease the level of DNA replication errors. Here we report the nucleotide sequence changes in each of the different antimutator dnaE alleles. For each a single, but different, amino acid substitution was found among the 1,160 amino acids of the protein. The observed substitutions are generally nonconservative. All affected residues are located in the central one-third of the protein. Some insight into the function of the regions of polymerase III containing the affected residues was obtained by amino acid alignment with other DNA polymerases. We followed the principles developed in 1990 by M. Delarue et al. who have identified in DNA polymerases from a large number of prokaryotic and eukaryotic sources three highly conserved sequence motifs, which are suggested to contain components of the polymerase active site. We succeeded in finding these three conserved motifs in polymerase III as well. However, none of the amino acid substitutions responsible for the antimutator phenotype occurred at these sites. This and other observations suggest that the effect of these mutations may be exerted indirectly through effects on polymerase conformation and/or DNA/polymerase interactions.


1996 ◽  
Vol 315 (2) ◽  
pp. 571-575 ◽  
Author(s):  
Colin D. PORTER ◽  
KURIBAYASHI KURIBAYASHI ◽  
Mohamed H. PARKAR ◽  
Dirk ROOS ◽  
Christine KINNON

NADPH oxidase cytochrome b558 consists of two subunits, gp91-phox and p22-phox, defects of which result in chronic granulomatous disease (CGD). The nature of the interaction between these subunits has yet to be determined. Absence of p22-phox in autosomal CGD patient-derived B-cell lines results in detectable levels of an incompletely glycosylated gp91-phox precursor. We have detected this same precursor species in four cell lines from patients with the X-linked form of the disease due to mutations in gp91-phox. Such mutations should delineate regions of gp91-phox important for its biosynthesis, including stable association with p22-phox. One mutation mapped to the putative FAD-binding domain, one mapped to a potential haem-binding domain, and two involved the region encoded by exon 3.


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