HYPERSTABILITY OF THE GENERAL LINEAR FUNCTIONAL EQUATION

PISZCZEK, MAGDALENA Korean Mathematical Society 2015 대한수학회보 Vol.52 No.6

We give some results on hyperstability for the general linear equation. Namely, we show that a function satisfying the linear equation approximately (in some sense) must be actually the solution of it.

HYPERSTABILITY OF THE GENERAL LINEAR FUNCTIONAL EQUATION

Magdalena Piszczek 대한수학회 2015 대한수학회보 Vol.52 No.6

We give some results on hyperstability for the general linear equation. Namely, we show that a function satisfying the linear equation approximately (in some sense) must be actually the solution of it.

Poster Session 1 : Analytical biochemistry Biochemical pharmacology and natural product chemistry Biotechnology ; On the possibility of Long wavelength, Long Lifetime and high quantum yield Luminophores

( Jung Sook Kang ),( Grzegorz Piszczek ),( Joseph R. Lakowicz ) 한국생화학분자생물학회 (구 한국생화학회) 2000 추계학술대회집 Vol.2000 No.-

Glutathionylation of Peroxiredoxin I Induces Decamer to Dimers Dissociation with Concomitant Loss of Chaperone Activity

Park, Ji Won,Piszczek, Grzegorz,Rhee, Sue Goo,Chock, P. Boon American Chemical Society 2011 Biochemistry Vol.50 No.15

<P>Reversible protein glutathionylation, a redox-sensitive regulatory mechanism, plays a key role in cellular regulation and cell signaling. Peroxiredoxins (Prxs), a family of peroxidases that is involved in removing H<SUB>2</SUB>O<SUB>2</SUB> and organic hydroperoxides, are known to undergo a functional change from peroxidase to molecular chaperone upon overoxidation of its catalytic cysteine. The functional change is caused by a structural change from low molecular weight oligomers to high molecular weight complexes that possess molecular chaperone activity. We reported earlier that Prx I can be glutathionylated at three of its cysteine residues, Cys52, -83, and -173 [<name name-style='western'>Park</name><etal>et al.</etal><x xml:space='preserve'> (</x>2009<x xml:space='preserve'>) </x>J. Biol. Chem., 284<x xml:space='preserve'>, </x>23364]. In this study, using analytical ultracentrifugation analysis, we reveal that glutathionylation of Prx I, WT, or its C52S/C173S double mutant shifted its oligomeric status from decamers to a population consisting mainly of dimers. Cys83 is localized at the putative dimer−dimer interface, implying that the redox status of Cys83 may play an important role in stabilizing the oligomeric state of Prx I. Studies with the Prx I (C83S) mutant show that while Cys83 is not essential for the formation of high molecular weight complexes, it affects the dimer−decamer equilibrium. Glutathionylation of the C83S mutant leads to accumulation of dimers and monomers. In addition, glutathionylation of Prx I, both the WT and C52S/C173S mutants, greatly reduces their molecular chaperone activity in protecting citrate synthase from thermally induced aggregation. Together, these results reveal that glutathionylation of Prx I promotes changes in its quaternary structure from decamers to smaller oligomers and concomitantly inactivates its molecular chaperone function.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bichaw/2011/bichaw.2011.50.issue-15/bi101373h/production/images/medium/bi-2010-01373h_0006.gif'></P>

DNA Dynamics: a Fluorescence Resonance Energy Transfer Study Using a Long-Lifetime Metal-Ligand Complex

Kang, Jung-Sook,Lakowicz, Joseph-R.,Piszczek, Grzegorz The Pharmaceutical Society of Korea 2002 Archives of Pharmacal Research Vol.25 No.2

Fluorescent probes bound to DNA typically display nanosecond decay times and reveal only nanosecond motions. We extend the time range of measurable DNA dynamics using $[Ru(pby)_2(dppz)]^{2+}$ (bpy=2.2'-bipyridine, dppz=dipyrido[3,2-a2',3'-c]phenazine) (RuBD) which displays a mean lifetime near 90 ns. To test the usefulness of RuBD as a probe for diffusive processes in calf thymus DNA, we compared the efficiencies of fluorescence resonance energy transfer (FRET) using three donors which display lifetimes near 5 ns for acridine orange (AO), 22 ns for ethidum bromide (EB) and 92 ns for RuBD, with nile blue (NB) as the acceptor. The F rster distances for AO-NB, EB-NB and RuBD-NB donor-acceptor pairs were 42.3, 52.3, and $30.6{\;}{\AA}$, respectively. All three donors showed dramatic decreases in fluorescence intensities and more rapid intensity decays with increasing NB concentrations. The intensity decays of AO and EB in the presence of varying concentrations of NB were satisfactorily described by the one-dimensional FRET model without diffusion (Blumen and Manz, 1979). In the case of the long-lifetime donor RuBD, the experimental phase and modulation somewhat deviated from the recovered values computed from this model. The recovered NB concentrations and FRET efficiencies from the model were slightly larger than the expected values, however, the recovered and expected values did not show a significant difference. Thus, it is suggested that the lifetime of RuBD is too short to measure diffusive processes in calf thymus DNA.

Olfactomedin 4 deletion induces colon adenocarcinoma in <i>Apc</i> ^<i>Min/+</i> mice

Liu, W,Li, H,Hong, S-H,Piszczek, G P,Chen, W,Rodgers, G P Nature Publishing Group 2016 Oncogene Vol.35 No.40

<P>Colon carcinogenesis is a multiple-step process involving the accumulation of a series of genetic and epigenetic alterations. The most commonly initiating event of intestinal carcinogenesis is mutation of the adenomatous polyposis coli (<I>APC</I>) gene, which leads to activation of the Wnt/β-catenin pathway. Olfactomedin 4 (OLFM4) has emerged as an intestinal stem-cell marker, but its biological function in the intestine remains to be determined. Here we show that <I>Olfm4</I> deletion induced colon adenocarcinoma in the distal colon of <I>Apc</I><SUP>Min/+</SUP> mice. Mechanistically, we found that <I>OLFM4</I> is a target gene of the Wnt/β-catenin pathway and can downregulate β-catenin signaling by competing with Wnt ligands for binding to Frizzled receptors, as well as by inhibition of the Akt-GSK-3β (Akt-glycogen synthase kinase-3β) pathway. We have shown that both Wnt and nuclear factor-κB (NF-κB) signaling were boosted in tumor tissues of <I>Apc Olfm4</I> double-mutant mice. These data establish OLFM4 as a critical negative regulator of the Wnt/β-catenin and NF-κB pathways that inhibits colon-cancer development initiated by <I>APC</I> mutation. In addition, <I>Olfm4</I> deletion significantly enhanced intestinal-crypt proliferation and inflammation induced by azoxymethane/dextran sodium sulfate. Thus, OLFM4 has an important role in the regulation of intestinal inflammation and tumorigenesis, and could be a potential therapeutic target for intestinal malignant tumors. Unlike the human colonic epithelium, the mouse colonic epithelium does not express OLFM4, but nevertheless, systemic OLFM4 deletion promotes colon tumorigenesis and that loss from mucosal neutrophils may have a role to play.</P>

Novel protective mechanism against irreversible hyperoxidation of peroxiredoxin: Nalpha-terminal acetylation of human peroxiredoxin II.

Seo, Jae Ho,Lim, Jung Chae,Lee, Duck-Yeon,Kim, Kyung Seok,Piszczek, Grzegorz,Nam, Hyung Wook,Kim, Yu Sam,Ahn, Taeho,Yun, Chul-Ho,Kim, Kanghwa,Chock, P Boon,Chae, Ho Zoon American Society for Biochemistry and Molecular Bi 2009 The Journal of biological chemistry Vol.284 No.20

<P>Peroxiredoxins (Prxs) are a group of peroxidases containing a cysteine thiol at their catalytic site. During peroxidase catalysis, the catalytic cysteine, referred to as the peroxidatic cysteine (C(P)), cycles between thiol (C(P)-SH) and disulfide (-S-S-) states via a sulfenic (C(P)-SOH) intermediate. Hyperoxidation of the C(P) thiol to its sulfinic (C(P)-SO(2)H) derivative has been shown to be reversible, but its sulfonic (C(P)-SO(3)H) derivative is irreversible. Our comparative study of hyperoxidation and regeneration of Prx I and Prx II in HeLa cells revealed that Prx II is more susceptible than Prx I to hyperoxidation and that the majority of the hyperoxidized Prx II formation is reversible. However, the hyperoxidized Prx I showed much less reversibility because of the formation of its irreversible sulfonic derivative, as verified with C(P)-SO(3)H-specific antiserum. In an attempt to identify the multiple hyperoxidized spots of the Prx I on two-dimensional PAGE analysis, an N-acetylated Prx I was identified as part of the total Prx I using anti-acetylated Lys antibody. Using peptidyl-Asp metalloendopeptidase (EC 3.4.24.33) peptide fingerprints, we found that N(alpha)-terminal acetylation (N(alpha)-Ac) occurred exclusively on Prx II after demethionylation. N(alpha)-Ac of Prx II blocks Prx II from irreversible hyperoxidation without altering its affinity for hydrogen peroxide. A comparative study of non-N(alpha)-acetylated and N(alpha)-terminal acetylated Prx II revealed that N(alpha)-Ac of Prx II induces a significant shift in the circular dichroism spectrum and elevation of T(m) from 59.6 to 70.9 degrees C. These findings suggest that the structural maintenance of Prx II by N(alpha)-Ac may be responsible for preventing its hyperoxidation to form C(P)-SO(3)H.</P>