Project description:IP- Mass Spec of INS1 cells treated with DHT or GLP1 and then subjected to IP of AR protein and subsequent mass spec to identify binding partners of AR relevant to Insulin signaling and secretion.
Project description:The enantioselective intermolecular C2-allylation of 3-substituted indoles is reported for the first time. This directing group-free approach relies on a chiral Ir-(P, olefin) complex and Mg(ClO4 )2 Lewis acid catalyst system to promote allylic substitution, providing the C2-allylated products in typically high yields (40-99?%) and enantioselectivities (83-99?% ee) with excellent regiocontrol. Experimental studies and DFT calculations suggest that the reaction proceeds via direct C2-allylation, rather than C3-allylation followed by in situ migration. Steric congestion at the indole-C3 position and improved ?-? stacking interactions have been identified as major contributors to the C2-selectivity.
Project description:BackgroundThe bifunctional enzyme β-carotene hydroxylase (CrtZ) catalyzes the hydroxylation of carotenoid β-ionone rings at the 3, 3' position regardless of the presence of keto group at 4, 4' position, which is an important step in the synthesis of astaxanthin. The level and substrate preference of CrtZ may have great effect on the amount of astaxanthin and the accumulation of intermediates.ResultsIn this study, the substrate preference of PCcrtZ from Paracoccus sp. PC1 and PAcrtZ from Pantoea Agglomerans were certified and were combined utilization for increase astaxanthin production. Firstly, PCcrtZ from Paracoccus sp. PC1 and PAcrtZ from P. Agglomerans were expressed in platform strains CAR032 (β-carotene producing strain) and Can004 (canthaxanthin producing strain) separately to identify their substrate preference for carotenoids with keto groups at 4,4' position or not. The results showed that PCcrtZ led to a lower zeaxanthin yield in CAR032 compared to that of PAcrtZ. On the contrary, higher astaxanthin production was obtained in Can004 by PCcrtZ than that of PAcrtZ. This demonstrated that PCCrtZ has higher canthaxanthin to astaxanthin conversion ability than PACrtZ, while PACrtZ prefer using β-carotene as substrate. Finally, Ast010, which has two copies of PAcrtZ and one copy of PCcrtZ produced 1.82 g/L of astaxanthin after 70 h of fed-batch fermentation.ConclusionsCombined utilization of crtZ genes, which have β-carotene and canthaxanthin substrate preference respectively, can greatly enhance the production of astaxanthin and increase the ratio of astaxanthin among total carotenoids.
Project description:The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact action mechanism of H3pT11 is poorly understood. Here, we identify Dot1-catalyzed H3K79 tri-methylation (H3K79me3) as the downstream effector of H3pT11 and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they synergically promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM-containing Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a novel histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.
Project description:We developed a novel in-vitro experimental method to characterize the protein-DNA interaction specificity and methylation sensitivity, we called Methyl-Spec-seq. In this data set, mouse ZFP57 (F1-F3) was used as a positive control example to show that Methyl-Spec-seq can determine the relative binding energy for variants with different methylation property, i.e., unmethylated, top hemimethylated, bottom hemimethylated, duplex methylated by either chemical synthesis or enzymatic treatment.
Project description:We developed a novel in-vitro experimental method to characterize the protein-DNA interaction specificity and methylation sensitivity, we called Methyl-Spec-seq. In this data set, mouse ZFP57 (F1-F3) was used as a positive control example to show that Methyl-Spec-seq can determine the relative binding energy for variants with different methylation property, i.e., unmethylated, top hemimethylated, bottom hemimethylated, duplex methylated by either chemical synthesis or enzymatic treatment.
Project description:We developed a novel in-vitro experimental method to characterize the protein-DNA interaction specificity and methylation sensitivity, we called Methyl-Spec-seq. In this data set, mouse AP1 was used as a positive control example to show that Methyl-Spec-seq can determine the relative binding energy for variants with different methylation property, i.e., unmethylated, top hemimethylated, bottom hemimethylated, duplex methylated by either chemical synthesis or enzymatic treatment.
Project description:We developed a novel in-vitro experimental method to characterize the protein-DNA interaction specificity and methylation sensitivity, we called Methyl-Spec-seq. In this data set, mouse HOXB13 (F1-F3) was used as a positive control example to show that Methyl-Spec-seq can determine the relative binding energy for variants with different methylation property, i.e., unmethylated, top hemimethylated, bottom hemimethylated, duplex methylated by either chemical synthesis or enzymatic treatment.
Project description:One of the fundamental questions of enzymology is how catalytic power is derived. This review focuses on recent developments in the structure--function relationships of chorismate-utilizing enzymes involved in siderophore biosynthesis to provide insight into the biocatalysis of pericyclic reactions. Specifically, salicylate synthesis by the two-enzyme pathway in Pseudomonas aeruginosa is examined. The isochorismate-pyruvate lyase is discussed in the context of its homologues, the chorismate mutases, and the isochorismate synthase is compared to its homologues in the MST family (menaquinone, siderophore, or tryptophan biosynthesis) of enzymes. The tentative conclusion is that the activities observed cannot be reconciled by inspection of the active site participants alone. Instead, individual activities must arise from unique dynamic properties of each enzyme that are tuned to promote specific chemistries.
Project description:A dinuclear Co(ii) complex supported by a modular, tunable redox-active ligand system is capable of selective C-H amination to form indolines from aryl azides in good yields at low (1 mol%) catalyst loading. The reaction is tolerant of medicinally relevant heterocycles, such as pyridine and indole, and can be used to form 5-, 6-, and 7-membered rings. The synthetic versatility obtained using low loadings of an earth abundant transition metal complex represents a significant advance in catalytic C-H amination technology.