Background NADPH provides reducing power for macromolecule synthesis and antioxidant defense. The pathways used to make NADPH under different physiological circumstances remain unclear. In growing cells, much NADPH production is coupled to nucleotide synthesis via the oxidative pentose phosphate and folate pathways. Here we examine, using isotope tracers and flux analysis, NADPH production rout...

Stoichiometrically, exact candidate pathways or mechanisms for deriving the rate law of a catalytic or complex reaction can be determined through the synthesis of networks of plausible elementary reactions constituting such pathways. A rigorous algorithmic method is proposed for executing this synthesis, which is exceedingly convoluted due to its combinatorial complexity. Such a method for synt...

L-Leucine is known to stimulate protein synthesis in L6 myotubes. In the present study, we examined the possible involvement of calcium signaling pathways in the stimulation of protein synthesis induced by L-leucine in L6 myotubes. After 16 h of treatment with L-leucine-depleted medium, the re-addition of L-leucine for 4 h augmented protein synthesis by about 50% as compared with an L-leucine-d...

PCNA ubiquitination in response to DNA damage leads to the recruitment of specialized translesion polymerases to the damage locus. This constitutes one of the initial steps in translesion synthesis (TLS)--a critical pathway for cell survival and for maintenance of genome stability. The recent crystal structure of ubiquitinated PCNA (Ub-PCNA) sheds light on the mode of association between the tw...

Nikkomycins are a group of peptidyl nucleoside antibiotics with potent fungicidal, insecticidal, and acaricidal activities. sanN was cloned from the partial genomic library of Streptomyces ansochromogenes 7100. Gene disruption and complementation analysis demonstrated that sanN is essential for nikkomycin biosynthesis in S. ansochromogenes. Primer extension assay indicated that sanN is transcri...

Bleomycin (BLM), an important clinically used antitumor compound, and its analogs are challenging to prepare by chemical synthesis. Genetic engineering of the biosynthetic pathway in the producer strain would provide an efficient and convenient method of generating new derivatives of this complex molecule in vivo. However, the BLM producing Streptomyces verticillus ATCC15003 has been refractory...

The multi-step synthesis of complex organic compounds from simpler precursors is one of the outstanding accomplishments and ongoing challenges of synthetic organic chemistry. Through the development and invention of synthesis strategies, methods and technologies, increasingly complex molecules can be assembled with designed structures and functions for a variety of medicinal, agrochemical and m...

Upon coexpression with Erwinia geranylgeranyldiphosphate (GGDP) synthase in Escherichia coli, C(30) carotenoid synthase CrtM from Staphylococcus aureus produces novel carotenoids with the asymmetrical C(35) backbone. The products of condensation of farnesyldiphosphate and GDP, C(35) structures comprise 40 to 60% of total carotenoid accumulated. Carotene desaturases and carotene cyclases from C(...

1. The maintenance of skeletal muscle mass is determined by a fine balance between protein synthesis and protein degradation. Skeletal mass is increased when there is a net gain in protein synthesis which can occur following progressive exercise training. In contrast, skeletal muscle mass is lost when degradation occurs more rapidly than synthesis and is observed in numerous conditions includin...

Cordycepin has been a traditional medicine in China and Korea for centuries. This study explored the inhibitory effect of cordycepin on melanogenesis and the relative molecular mechanisms. Cordycepin inhibited melanin synthesis-related enzymes, such as tyrosinase, tyrosinase-related protein-1 (TRP1) and tyrosinase-related protein-2 (TRP2). α-MSH a...