The intrinsically disordered N-terminal region of mouse DNA polymerase alpha mediates its interaction with POT1a/b at telomeres.

Mouse telomerase and the DNA polymerase alpha-primase complex elongate the leading and lagging strands of telomeres, respectively. To elucidate the molecular mechanism of lagging strand synthesis, we investigated the interaction between DNA polymerase alpha and two paralogs of the mouse POT1 telomere-binding protein (POT1a and POT1b). Yeast two-hybrid analysis and a glutathione S-transferase pull-down assay indicated that the C-terminal region of POT1a/b binds to the intrinsically disordered N-terminal region of p180, the catalytic subunit of mouse DNA polymerase alpha.

Crystal structures of hydroxymethylbilane synthase complexed with a substrate analog: a single substrate-binding site for four consecutive condensation steps.

Hydroxymethylbilane synthase (HMBS), which is involved in the heme biosynthesis pathway, has a dipyrromethane cofactor and combines four porphobilinogen (PBG) molecules to form a linear tetrapyrrole, hydroxymethylbilane. Enzyme kinetic study of human HMBS using a PBG-derivative, 2-iodoporphobilinogen (2-I-PBG), exhibited noncompetitive inhibition with the inhibition constant being 5.4 ± 0.

Highlighting the potential utility of MBP crystallization chaperone for Arabidopsis BIL1/BZR1 transcription factor-DNA complex.

The maltose-binding protein (MBP) fusion tag is one of the most commonly utilized crystallization chaperones for proteins of interest. Recently, this MBP-mediated crystallization technique was adapted to Arabidopsis thaliana (At) BRZ-INSENSITIVE-LONG (BIL1)/BRASSINAZOLE-RESISTANT (BZR1), a member of the plant-specific BZR TFs, and revealed the first structure of AtBIL1/BZR1 in complex with target DNA. However, it is unclear how the fused MBP affects the structural features of the AtBIL1/BZR1-DNA complex.

Identification of IscU residues critical for de novo iron-sulfur cluster assembly.

IscU is a central component of the ISC machinery and serves as a scaffold for the de novo assembly of iron-sulfur (Fe-S) clusters prior to their delivery to target apo-Fe-S proteins. However, the molecular mechanism is not yet fully understood. In this study, we have conducted mutational analysis of E.

Triazole Ureas Covalently Bind to Strigolactone Receptor and Antagonize Strigolactone Responses.

Strigolactones, a class of plant hormones with multiple functions, mediate plant-plant and plant-microorganism communications in the rhizosphere. In this study, we developed potent strigolactone antagonists, which covalently bind to the strigolactone receptor D14, by preparing an array of triazole urea compounds. Using yeast two-hybrid and rice-tillering assays, we identified a triazole urea compound KK094 as a potent inhibitor of strigolactone receptors.

Structural basis for brassinosteroid response by BIL1/BZR1.

BRZ-INSENSITIVE-LONG HYPOCOTYL 1 (BIL1)/BRASSINAZOLE-RESISTANT 1 (BZR1) is a master transcription factor of brassinosteroid (BR) signalling. The varieties of nucleobase recognition of the NN-BRRE-core motif (NNCGTG), one of variant G-box motifs, distinguish BIL1/BZR1 from basic helix-loop-helix transcription factors, underlying the specific regulation of BR-responsive genes. Here, we show the non-canonical bHLH dimer formation of BIL1/BZR1 to optimize the interaction network with DNA and the orientation of a key residue for NN-BRRE-core motif recognition.

Rationally Designed Strigolactone Analogs as Antagonists of the D14 Receptor.

Strigolactones (SLs) are plant hormones that inhibit shoot branching and act as signals in communications with symbiotic fungi and parasitic weeds in the rhizosphere. SL signaling is mediated by DWARF14 (D14), which is an α/β-hydrolase that cleaves SLs into an ABC tricyclic lactone and a butenolide group (i.e.

Methyl phenlactonoates are efficient strigolactone analogs with simple structure.

Strigolactones (SLs) are a new class of phytohormones that also act as germination stimulants for root parasitic plants, such as Striga spp., and as branching factors for symbiotic arbuscular mycorrhizal fungi. Sources for natural SLs are very limited.

Mapping the key residues of SufB and SufD essential for biosynthesis of iron-sulfur clusters.

Biogenesis of iron-sulfur (Fe-S) clusters is an indispensable process in living cells. In Escherichia coli, the SUF biosynthetic system consists of six proteins among which SufB, SufC and SufD form the SufBCD complex, which serves as a scaffold for the assembly of nascent Fe-S cluster. Despite recent progress in biochemical and structural studies, little is known about the specific regions providing the scaffold.

A substrate-bound structure of cyanobacterial biliverdin reductase identifies stacked substrates as critical for activity.

Biliverdin reductase catalyses the last step in haem degradation and produces the major lipophilic antioxidant bilirubin via reduction of biliverdin, using NAD(P)H as a cofactor. Despite the importance of biliverdin reductase in maintaining the redox balance, the molecular details of the reaction it catalyses remain unknown. Here we present the crystal structure of biliverdin reductase in complex with biliverdin and NADP.

Functional Dynamics Revealed by the Structure of the SufBCD Complex, a Novel ATP-binding Cassette (ABC) Protein That Serves as a Scaffold for Iron-Sulfur Cluster Biogenesis.

ATP-binding cassette (ABC)-type ATPases are chemomechanical engines involved in diverse biological pathways. Recent genomic information reveals that ABC ATPase domains/subunits act not only in ABC transporters and structural maintenance of chromosome proteins, but also in iron-sulfur (Fe-S) cluster biogenesis. A novel type of ABC protein, the SufBCD complex, functions in the biosynthesis of nascent Fe-S clusters in almost all Eubacteria and Archaea, as well as eukaryotic chloroplasts.

Crystal structure of the catalase-peroxidase KatG W78F mutant from Synechococcus elongatus PCC7942 in complex with the antitubercular pro-drug isoniazid.

Isoniazid (INH) is a pro-drug that has been extensively used to treat tuberculosis. INH is activated by the heme enzyme catalase-peroxidase (KatG), but the mechanism of the activation is poorly understood, in part because the INH binding site has not been clearly established. Here, we observed that a single-residue mutation of KatG from Synechococcus elongatus PCC7942 (SeKatG), W78F, enhances INH activation.

The crystal structure of isoniazid-bound KatG catalase-peroxidase from Synechococcus elongatus PCC7942.

Isoniazid (INH) is one of the most effective antibiotics against tuberculosis. INH is a prodrug that is activated by KatG. Although extensive studies have been performed in order to understand the mechanism of KatG, even the binding site of INH in KatG remains controversial.

Mapping of protein-protein interaction sites in the plant-type [2Fe-2S] ferredoxin.

Knowing the manner of protein-protein interactions is vital for understanding biological events. The plant-type [2Fe-2S] ferredoxin (Fd), a well-known small iron-sulfur protein with low redox potential, partitions electrons to a variety of Fd-dependent enzymes via specific protein-protein interactions. Here we have refined the crystal structure of a recombinant plant-type Fd I from the blue green alga Aphanothece sacrum (AsFd-I) at 1.

Aneuploidy predicts outcome in patients with endometrial carcinoma and is related to lack of CDH13 hypermethylation.

Purpose: Many investigators have reported that aneuploidy detected by flow cytometry is a useful prognostic marker in patients with endometrial cancer. Laser scanning cytometry (LSC) is a technology similar to flow cytometry but is more feasible for clinical laboratory use. We evaluated the usefulness of DNA ploidy detected by LSC as a prognostic marker in patients with endometrial cancer and investigated genetic and epigenetic factors related to aneuploidy.

Syndecan-1 expression in cancer of the uterine cervix: association with lymph node metastasis.

The development of carcinoma is associated with alterations in the expression of many cell adhesion molecules. Syndecan-1 is a cell surface proteoglycan that binds cells to the extracellular matrix and changes its expression following malignant transformation in some tumors. Our purpose was to examine the pattern of syndecan-1 expression in cancer of the uterine cervix and assess the clinicopathological significance of syndecan-1 expression.