Publications by authors named "Yasumitsu Sakamoto"

It is established that reverse hydroxamate analogs of fosmidomycin inhibit the growth of by inhibiting 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), the second enzyme of the non-mevalonate pathway, which is absent in humans. Recent biochemical studies have demonstrated that novel reverse fosmidomycin analogs with phenylalkyl substituents at the hydroxamate nitrogen exhibit inhibitory activities against DXR at the nanomolar level. Moreover, crystallographic analyses have revealed that the phenyl moiety of the -phenylpropyl substituent is accommodated in a previously unidentified subpocket within the active site of DXR.

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Reverse analogs of the phosphonohydroxamic acid antibiotic fosmidomycin are potent inhibitors of the nonmevalonate isoprenoid biosynthesis enzyme 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, IspC) of . Some novel analogs with large phenylalkyl substituents at the hydroxamic acid nitrogen exhibit nanomolar DXR inhibition and potent growth inhibition of parasites coupled with good parasite selectivity. X-ray crystallographic studies demonstrated that the -phenylpropyl substituent of the newly developed lead compound is accommodated in a subpocket within the DXR catalytic domain but does not reach the NADPH binding pocket of the -terminal domain.

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DPP8/9 inhibition induces either pyroptotic or apoptotic cell death in hematological malignancies. We previously reported that treatment with the DPP8/9 inhibitor 1G244 resulted in apoptotic cell death in myeloma, and our current study further evaluates the mechanism of action of 1G244 in different blood cancer cell lines. Specifically, 1G244 inhibited DPP9 to induce GSDMD-mediated-pyroptosis at low concentrations and inhibited DPP8 to cause caspase-3-mediated-apoptosis at high concentrations.

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The emergence of drug-resistant bacteria has become a major problem worldwide. Bacterial dipeptidyl peptidases 7 and 11 (DPP7s and DPP11s), belonging to the family-S46 peptidases, are important enzymes for bacterial growth and are not present in mammals. Therefore, specific inhibitors for these peptidases are promising as potential antibiotics.

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Antimicrobial resistance is a global public threat and raises the need for development of new antibiotics with a novel mode of action. The dipeptidyl peptidase 11 from Porphyromonas gingivalis (PgDPP11) belongs to a new class of serine peptidases, family S46. Because S46 peptidases are not found in mammals, these enzymes are attractive targets for novel antibiotics.

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Dipeptidyl peptidase IV (DPP IV, DPP4, or DAP IV) preferentially cleaves substrate peptides with Pro or Ala at the P1 position. The substrate recognition mechanism has been fully elucidated for mammalian DPP IV by crystal structure analyses but not for bacterial orthologues. Here, we report the crystal structures of a bacterial DPP IV (PmDAP IV) in its free form and in complexes with two kinds of dipeptides as well as with a non-peptidyl inhibitor at 1.

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Dipeptidyl aminopeptidase IV (DAP IV or DPP IV) from Pseudoxanthomonas mexicana WO24 (PmDAP IV) preferentially cleaves substrate peptides with Pro or Ala at the P1 position [NH-P2-P1(Pro/Ala)-P1'-P2'…]. For crystallographic studies, the periplasmic form of PmDAP IV was overproduced in Escherichia coli, purified and crystallized in complex with the tripeptide Lys-Pro-Tyr using the hanging-drop vapour-diffusion method. Kinetic parameters of the purified enzyme against a synthetic substrate were also determined.

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The F sector of ATP synthase (FF) synthesizes or hydrolyses ATP via a rotational catalysis mechanism that couples chemical reaction with subunit rotation. Phytopolyphenols such as curcumin can inhibit bulk phase F ATPase activity by extending the catalytic dwell time during subunit rotation (Sekiya, M., Hisasaka, R.

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Background: The filamentous fungus Trichoderma reesei (anamorph of Hypocrea jecorina) produces increased cellulase expression when grown on cellulose or its derivatives as a sole carbon source. It has been believed that β-glucosidases of T. reesei not only metabolize cellobiose but also contribute in the production of inducers of cellulase gene expression by their transglycosylation activity.

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Aim: To identify non-quinazoline kinase inhibitors effective against drug resistant mutants of epidermal growth factor receptor (EGFR).

Methods: A kinase inhibitor library was subjected to screening for specific inhibition pertaining to the in vitro kinase activation of EGFR with the gatekeeper mutation T790M, which is resistant to small molecular weight tyrosine kinase inhibitors (TKIs) for EGFR in non-small cell lung cancers (NSCLCs). This inhibitory effect was confirmed by measuring autophosphorylation of EGFR T790M/L858R in NCI-H1975 cells, an NSCLC cell line harboring the gatekeeper mutation.

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Article Synopsis
  • PgDPP11 is an enzyme from a bacteria called Porphyromonas gingivalis that helps break down proteins, especially those with certain building blocks called Asp or Glu.
  • Scientists studied the structure of PgDPP11 and found an important part (Arg673) that helps it recognize its specific targets.
  • Since this enzyme isn’t found in humans, it could be a good target for new antibiotics to fight infections caused by harmful bacteria.
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Dipeptidyl peptidase 11 from Porphyromonas gingivalis (PgDPP11) preferentially cleaves substrate peptides with Asp and Glu at the P1 position [NH2-P2-P1(Asp/Glu)-P1'-P2'...

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The dipeptidyl aminopeptidase BII (DAP BII) belongs to a serine peptidase family, S46. The amino acid sequence of the catalytic unit of DAP BII exhibits significant similarity to those of clan PA endopeptidases, such as chymotrypsin. However, the molecular mechanism of the exopeptidase activity of family S46 peptidase is unknown.

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Dipeptidyl aminopeptidase BII from Pseudoxanthomonas mexicana WO24 (DAP BII) is able to cleave a variety of dipeptides from the amino-terminus of substrate peptides. For crystallographic studies, DAP BII was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data to 2.

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The exopeptidases of family S46 are exceptional, as the closest homologs of these enzymes are the endopeptidases of clan PA. The three-dimensional structure of S46 enzymes is unknown and only one of the catalytic residues, the serine, has been identified. The catalytic histidine and aspartate residues are not experimentally identified.

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Autotaxin (ATX), which is also known as ectonucleotide pyrophosphatase/phosphodiesterase 2 (NPP2 or ENPP2) or phosphodiesterase Iα (PD-Iα), is an extracellular lysophospholipase D which generates lysophosphatidic acid (LPA) from lysophosphatidylcholine (LPC). ATX stimulates tumour-cell migration, angiogenesis and metastasis and is an attractive target for cancer therapy. For crystallographic studies, the α isoform of human ATX was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method.

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Chitosan is degraded to glucosamine (GlcN) by chitosanase and exo-beta-D-glucosaminidase (GlcNase). GlcNase from Trichoderma reesei (Gls93) is a 93 kDa extracellular protein composed of 892 amino acids. The enzyme liberates GlcN from the nonreducing end of the chitosan chain in an exo-type manner and belongs to glycoside hydrolase family 2.

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2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNP) is found mainly in the central nervous system of vertebrates and catalyzes the hydrolysis of 2',3'-cyclic nucleotides to produce 2'-nucleotides in vitro. Recently, Several 2H phosphodiesterase super family protein structures have been determined by X-ray crystallography and NMR spectroscopy. Here we report the structure-function relationship studies of two hydrophobic residues in CNP family proteins.

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2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNP) is found mainly in the central nervous system of vertebrates and catalyzes the hydrolysis of 2',3'-cyclic nucleotides to produce 2'-nucleotides in vitro. Recently, CNP has been identified as a member of the 2H phosphoesterase superfamily. Here we have determined the crystal structure of the catalytic fragment of human CNP (hCNP-CF) at 1.

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2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNP), a member of the 2H phosphoesterase superfamily, is firmly bound to brain white matter and found mainly in the central nervous system of vertebrates, and it catalyzes the hydrolysis of 2',3'-cyclic nucleotide to produce 2'-nucleotide. Recent studies on CNP-knockout mice have revealed that the absence of CNP causes axonal swelling and neuronal degeneration. Here, the crystal structure of the catalytic fragment (CF) of human CNP (hCNP-CF) is solved at 1.

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The catalytic fragment of human 2',3'-cyclic nucleotide 3'-phosphodiesterase (hCNP-CF) has been crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 300 as the precipitating agent. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 44.39, b = 55.

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S-adenosyl-l-homocysteine hydrolase from a malaria parasite Plasmodium falciparum (PfSAHH) has been crystallized by the vapor diffusion method. The crystals belong to an orthorhombic space group P212121 with the cell dimensions of a = 76.66 A, b = 86.

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