Other Chemistry Commons^™

Iterative Assembly Of Two Separate Polyketide Chains By The Same Single-Module Bacterial Polyketide Synthase In The Biosynthesis Of Hsaf, Yaoyao Li, Haotong Chen, Yanjiao Ding, Yunxuan Xie, Haoxin Wang, Ronald Cerny, Yuemao Shen, Liangcheng Du

Ronald Cerny Publications

HSAF (1) was isolated from the biocontrol agent Lysobacter enzymogenes (Figure 1).^[1-4]

This bacterial metabolite belongs to polycyclic tetramate macrolactams (PTM) that are

emerging as a new class of natural products with distinct structural features. ^{[5, 6]} HSAF

exhibits a potent antifungal activity and shows a novel mode of action.^[1-4] The HSAF

biosynthetic gene cluster contains only a single-module hybrid polyketide synthasenonribosomal

peptide synthetase (PKS-NRPS), although the PTM scaffold is apparently

derived from two separate hexaketide chains and an ornithine residue.^[1-4] This suggests that

the same PKS module would act not only iteratively, but also …

Overexpression Of Human Fatty Acid Transport Protein 2/Very Long Chain Acyl-Coa Synthetase 1 (Fatp2/Acsvl1) Reveals Distinct Patterns Of Trafficking Of Exogenous Fatty Acids, Elaina M. Melton, Ronald Cerny, Concetta C. Dirusso, Paul N. Black

Ronald Cerny Publications

In mammals, the fatty acid transport proteins (FATP1 through FATP6) are members of a highly conserved family of proteins, which function in fatty acid transport proceeding through vectorial acylation and in the activation of very long chain fatty acids, branched chain fatty acids and secondary bile acids. FATP1, 2 and 4, for example directly function in fatty acid transport and very long chain fatty acids activation while FATP5 does not function in fatty acid transport but activates secondary bile acids. In the present work, we have used stable isotopically labeled fatty acids differing in carbon length and saturation in cells …

Unusual Activities Of The Thioesterase Domain For The Biosynthesis Of The Polycyclic Tetramate Macrolactam Hsaf In Lysobacter Enzymogenes C3, Lili Lou, Haotong Chen, Ronald Cerny, Yaoyao Li, Yuemao Shen, Liangcheng Du

Ronald Cerny Publications

HSAF is an antifungal natural product with a new mode of action. A rare bacterial iterative PKSNRPS assembles the HSAF skeleton. The biochemical characterization of the NRPS revealed that the thioesterase (TE) domain possesses the activities of both a protease and a peptide ligase. Active site mutagenesis, circular dichroism spectra and homology modeling of the TE structure suggested that the TE may possess uncommon features that may lead to the unusual activities. The iterative PKS-NRPS is found in all polycyclic tetramate macrolactam gene clusters, and the unusual activities of the TE may be common to this type of hybrid PKS-NRPS.

Human Fatty Acid Transport Protein 2a/Very Long Chain Acyl-Coa Synthetase 1 (Fatp2a/Acsvl1) Has A Preference In Mediating The Channeling Of Exogenous N-3 Fatty Acids Into Phosphatidylinositol, Elaina M. Melton, Ronald Cerny, Paul A. Watkins, Concetta C. Dirusso, Paul N. Black

Ronald Cerny Publications

The trafficking of fatty acids across the membrane and into downstream metabolic pathways requires their activation to CoA thioesters. Members of the fatty acid transport protein/ very long chain acyl-CoA synthetase (FATP/Acsvl) family are emerging as key players in the trafficking of exogenous fatty acids into the cell and in intracellular fatty acid homeostasis.We have expressed two naturally occurring splice variants of human FATP2 (Acsvl1) in yeast and 293T-REx cells and addressed their roles in fatty acid transport, activation, and intracellular trafficking. Although both forms (FATP2a (Mr 70,000) and FATP2b (Mr 65,000 and lacking exon3, which encodes part of the …

Structure Function Analysis Of An Adp-Ribosyltransferase Type Iii Effector And Its Rna-Binding Target In Plant Immunity, Byeong-Ryool Jeong, Yan Lin, Anna Joe, Ming Guo, Christin Korneli, Huirong Yang, Ping Wang, Min Yu, Ronald Cerny, Dorothee Staiger, James R. Alfano, Yanhui Xu

Ronald Cerny Publications

Background: HopU1 ADP-ribosylates GRP7, suppressing plant immunity.

Results: The HopU1 structure has two novel loops required for GRP7 recognition, and HopU1 ribosylates GRP7 at an arginine in position 49 disrupting its function.

Conclusion: HopU1 targets a conserved arginine in GRP7, disabling its ability to bind immunity-related RNA.

Significance: The mechanistic details of how HopU1 recognizes its substrate reveal how HopU1 contributes to pathogenesis.

Overexpression Of Galnac-Transferase Galnac-T3 Promotes Pancreatic Cancer Cell Growth, Keisuke Taniuchi, Ronald Cerny, Aki Tanouchi, Kimitoshi Kohno, Norihiro Kotani, Koichi Honke, Toshiji Saibara, Michael A. Hollingsworth

Ronald Cerny Publications

O-linked glycans of secreted and membrane bound proteins play an important role in the pathogenesis of pancreatic cancer by modulating immune responses, inflammation, and tumorigenesis. A critical aspect of O-glycosylation, the position at which proteins are glycosylated with N-acetyl-galactosamine on serine and threonine residues, is regulated by the substrate specificity of UDP-GalNAc: polypeptide N-acetylgalactosaminyl-transferases (GalNAc-Ts). Thus, GalNAc-Ts regulate the first committed step in O-glycosylated protein biosynthesis, determine sites of O-glycosylation on proteins, and are important for understanding normal and carcinoma-associated O-glycosylation. We have found that one of these enzymes, GalNAc-T3, is overexpressed in …

Improved Arene Fluorination Methodology For I(Iii) Salts, Bijia Wang, Linlin Qin, Kiel D. Neumann, Shriharsha Uppaluri, Ronald Cerny, Stephen G. Dimagno

Ronald Cerny Publications

The use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts results in dramatically improved yields of fluorinated arenes from diaryliodonium salts. This methodology is shown to “scale down” to the conditions used typically for radiotracer synthesis.

Androgen-Stimulated Udp-Glucose Dehydrogenase Expression Limits Prostate Androgen Availability Without Impacting Hyaluronan Levels, Qin Wei, Robert Galbenus, Ashraf Raza, Ronald Cerny, Melanie A. Simpson

Ronald Cerny Publications

UDP-glucose dehydrogenase (UGDH) oxidizes UDP-glucose to UDP-glucuronate, an essential precursor for production of hyaluronan (HA), proteoglycans, and xenobiotic glucuronides. High levels of HA turnover in prostate cancer are correlated with aggressive progression. UGDH expression is high in the normal prostate even though HA accumulation is virtually undetectable. Thus, its normal role in the prostate may be to provide precursors for glucuronosyltransferase enzymes, which inactivate and solubilize androgens by glucuronidation. In this report, we quantified androgen dependence of UGDH, glucuronosyltransferase, and HA synthase expression. Androgen dependent and independent human prostate cancer cell lines were used to test the effects of UGDH …

Phosphorylation Of Muc1 By Met Modulates Interaction With P53 And Mmp1 Expression, Pankaj K. Singh, Michelle E. Behrens, John P. Eggers, Ronald Cerny, Jennifer M. Bailey, Kandavel Shanmugam, Sandra J. Gendler, Eric P. Bennett, Michael A. Hollingsworth

Ronald Cerny Publications

MUC1, a transmembrane mucin, is a key modulator of several signaling pathways that affect oncogenesis, motility, and cell morphology. The interaction of MUC1 cytoplasmic tail (MUC1CT) with signal transducers and its nuclear translocation and subsequent biological responses are believed to be regulated by phosphorylation status, but the precise mechanisms by which this occurs remain poorly defined. We detected a novel association between the Met receptor tyrosine kinase and the MUC1CT. Met catalyzed phosphorylation of tyrosine at YHPM in the MUC1CT. Stimulation of S2-013.MUC1F pancreatic cancer cells with hepatocyte growth factor facilitated nuclear localization of MUC1CT, as determined by real time …

Phosphorylation Of Claudin-5 And Occludin By Rho Kinase In Brain Endothelial Cells, Masaru Yamamoto, Servio H. Ramirez, Shinji Sato, Tomomi Kiyota, Ronald Cerny, Kozo Kaibuchi, Yuri Persidsky, Tsuneya Ikezu

Ronald Cerny Publications

Critical to the proper maintenance of blood-brainbarrier (BBB) integrity are the endothelial tight junctions (TJs). Posttranslational modifications of essential endothelial TJ proteins, occludin and claudin-5, contribute and possibly disrupt BBB integrity. Our previous work has shown that Rho kinase (RhoK) activation mediates occludin and claudin-5 phosphorylation resulting in diminished barrier tightness and enhanced monocyte migration across BBB in the setting of human immunodeficiency virus-1 encephalitis (HIVE). To determine whether RhoK can directly phosphorylate TJ proteins, we examined phosphorylation of cytoplasmic domains of recombinant claudin- 5 and occludin by RhoK. We found that RhoK predominately phosphorylated two sites on occludin (T382 …

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith

Ronald Cerny Publications

Disulfide bonding of lens crystallins contributes to the aggregation and insolubilization of these proteins that leads to cataract. A high concentration of reduced glutathione is believed to be key in preventing oxidation of crystallin sulfhydryls to form disulfide bonds. This protective role is decreased in aged lenses because of lower glutathione levels, especially in the nucleus. We recently found that human [1]-crystallins undergo S-methylation at exposed cysteine residues, a reaction that may prevent disulfide bonding. We report here that βA1/A3-crystallins are also methylated at specific cysteine residues and are the most heavily methylated of the human lens crystallins. Among the …