Jo M

References (3)

Title : A structure-function analysis of chlorophyllase reveals a mechanism for activity regulation dependent on disulfide bonds - Jo_2023_J.Biol.Chem__102958
Author(s) : Jo M , Knapp M , Boggs DG , Brimberry M , Donnan PH , Bridwell-Rabb J
Ref : Journal of Biological Chemistry , :102958 , 2023
Abstract : Chlorophyll (Chl) pigments are used by photosynthetic organisms to facilitate light capture and mediate the conversion of sunlight into chemical energy. Due to the indispensable nature of this pigment, and its propensity to form reactive oxygen species, organisms heavily invest in its biosynthesis, recycling, and degradation. One key enzyme implicated in these processes is chlorophyllase, an alpha/beta hydrolase that hydrolyzes the phytol tail of Chl pigments to produce chlorophyllide (Chlide) molecules. This enzyme was discovered a century ago, but despite its importance to diverse photosynthetic organisms, there are still many missing biochemical details regarding how chlorophyllase functions. Here, we present the 4.46- resolution crystal structure of chlorophyllase from Triticum aestivum. This structure reveals the dimeric architecture of chlorophyllase, the arrangement of catalytic residues, an unexpected divalent metal ion binding site, and a substrate binding site that can accommodate a diverse range of pigments. Further, this structure exhibits the existence of both intermolecular and intramolecular disulfide bonds. We investigated the importance of these architectural features using enzyme kinetics, mass spectrometry, and thermal shift assays. Through this work, we demonstrated that the oxidation state of the Cys residues is imperative to the activity and stability of chlorophyllase, illuminating a biochemical trigger for responding to environmental stress. Additional bioinformatics analysis of the chlorophyllase enzyme family reveals widespread conservation of key catalytic residues and the identified "redox switch" among other plant chlorophyllase homologs, thus revealing key details regarding the structure-function relationships in chlorophyllase.
ESTHER : Jo_2023_J.Biol.Chem__102958
PubMedSearch : Jo_2023_J.Biol.Chem__102958
PubMedID: 36731794
Gene_locus related to this paper: wheat-w5h2c8

Title : Selective production of 1-monocaprin by porcine liver carboxylesterase-catalyzed esterification: Its enzyme kinetics and catalytic performance - Park_2016_Enzyme.Microb.Technol_82_51
Author(s) : Park KM , Lee JH , Hong SC , Kwon CW , Jo M , Choi SJ , Kim K , Chang PS
Ref : Enzyme Microb Technol , 82 :51 , 2016
Abstract : Porcine liver carboxylesterase (PLE) belongs to carboxylesterase family (EC 3.1.1.1) as a serine-type esterase. The PLE-catalyzed esterification of capric acid with glycerol in reverse micelles was investigated on the catalytic performance and enzyme kinetics. The most suitable structure of reverse micelles was comprised of isooctane (reaction medium) and bis(2-ethylhexyl) sodium sulfosuccinate (AOT, anionic surfactant) with 0.1 of R-value ([water]/[surfactant]) and 3.0 of G/F-value ([glycerol]/[fatty acid]) for the PLE-catalyzed esterification. In the aspect of regio-selectivity, the PLE mainly produced 1-monocaprin without any other products (di- and/or tricaprins of subsequent reactions). Furthermore, the degree of esterification at equilibrium state (after 4h from the initiation) was 62.7% under the optimum conditions at pH 7.0 and 60 degrees C. Based on Hanes-Woolf plot, the apparent Km and Vmax values were calculated to be 16.44mM and 38.91muM/min/mg protein, respectively.
ESTHER : Park_2016_Enzyme.Microb.Technol_82_51
PubMedSearch : Park_2016_Enzyme.Microb.Technol_82_51
PubMedID: 26672448
Gene_locus related to this paper: pig-EST1

Title : Lipoprotein-associated phospholipase A is related to plaque stability and is a potential biomarker for acute coronary syndrome - Chung_2014_Yonsei.Med.J_55_1507
Author(s) : Chung H , Kwon HM , Kim JY , Yoon YW , Rhee J , Choi EY , Min PK , Hong BK , Rim SJ , Yoon JH , Lee SJ , Park JK , Kim MH , Jo M , Yang JH , Lee BK
Ref : Yonsei Med J , 55 :1507 , 2014
Abstract : PURPOSE: Plasma lipoprotein-associated phospholipase A (Lp-PLA) binds to low-density lipoprotein. The levels of Lp-PLA reflect the plaque burden, and are upregulated in acute coronary syndrome (ACS). We investigated the diagnostic value of Lp-PLA2 levels and found that it might be a potential biomarker for ACS. MATERIALS AND METHODS: We classified 226 study participants into three groups: patients without significant stenosis (control group), patients with significant stenosis with stable angina (SA group), and patients with ACS (ACS group). RESULTS: Lp-PLA and high-sensitivity C-reactive protein (hs-CRP) levels were significantly greater in the ACS group than in the SA group (p=0.044 and p=0.029, respectively). Multivariate logistic regression analysis revealed that Lp-PLA levels are significantly associated with ACS (odds ratio=1.047, p=0.013). The addition of Lp-PLA to the ACS model significantly increased the global ^2 value over traditional risk factors (28.14 to 35.602, p=0.006). The area under the receiver operating characteristic curve for Lp-PLA was 0.624 (p=0.004). The addition of Lp-PLA level to serum hs-CRP concentration yielded an integrated discrimination improvement of 0.0368 (p=0.0093, standard error: 0.0142) and improved the ability to diagnose ACS. CONCLUSION: Lp-PLA levels are related to plaque stability and might be a diagnostic biomarker for ACS.
ESTHER : Chung_2014_Yonsei.Med.J_55_1507
PubMedSearch : Chung_2014_Yonsei.Med.J_55_1507
PubMedID: 25323886