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Full-Text Articles in Enzymes and Coenzymes
Cloning And Characterization Of The Escherichia Coli Heptosyltransferase Iii: Exploring Substrate Specificity In Lipopolysaccaride Core Biosynthesis, Jagadesh Mudapaka, Erika Taylor
Cloning And Characterization Of The Escherichia Coli Heptosyltransferase Iii: Exploring Substrate Specificity In Lipopolysaccaride Core Biosynthesis, Jagadesh Mudapaka, Erika Taylor
Erika A. Taylor, Ph.D.
Bacterial lipopolysaccharide (LPS) molecules are an important cell surface component that enables adhesion to surfaces and cell motility, amongst other functions. In Escherichia coli, there are multiple Heptosyltransferase enzymes involved in the biosynthesis of the core region of LPS. Here we describe the first ever cloning, expression, purification and characterization of Heptosyltransferase III (HepIII) from E. coli, which catalyzes the addition of an l-glycero-d-manno-heptose (Hep) residue to the growing LPS core via an α(1→7) bond. Inspired by results from our lab on the E. coli HepI, we assessed the catalytic efficiency with phospho-Hep2-Kdo2-Lipid A (PH2K2LA) and two deacylated analogues.
Anopheles Gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure And Inhibition, Erika Taylor, Agnes Rinaldo-Matthis, Lei Li, Mahmoud Ghanem, Keith Hazleton, M. Belen Cassera, Steven Almo, Vern Schramm
Anopheles Gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure And Inhibition, Erika Taylor, Agnes Rinaldo-Matthis, Lei Li, Mahmoud Ghanem, Keith Hazleton, M. Belen Cassera, Steven Almo, Vern Schramm
Erika A. Taylor, Ph.D.
The purine salvage pathway of Anopheles gambiae, a mosquito that transmits malaria, has been identified in genome searches on the basis of sequence homology with characterized enzymes. Purine nucleoside phosphorylase (PNP) is a target for the development of therapeutic agents in humans and purine auxotrophs, including malarial parasites. The PNP from Anopheles gambiae (AgPNP) was expressed in Escherichia coli and compared to the PNPs from Homo sapiens (HsPNP) and Plasmodium falciparum (PfPNP). AgPNP has kcat values of 54 and 41 s-1 for 2'-deoxyinosine and inosine, its preferred substrates, and 1.0 s-1 for guanosine. However, the chemical step is fast for …