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Nitrite, a ubiquitous stable oxidation byproduct of nitric oxide (NO) metabolism, is now entering the pantheon of signaling biochemical molecules. Nitrite may have the unique properties of a blood and tissue NO reservoir activated by physiological and pathological hypoxia.
Chemical biology, broadly defined as the application of chemistry to the study of molecular events in biological systems, presents an opportunity for the reorganization and revitalization of the chemistry curriculum.
From the complex behavior of multicomponent signaling networks to the structures of large protein complexes and aggregates, questions once viewed as daunting are now being tackled fearlessly by protein scientists. The 19th Annual Symposium of the Protein Society in Boston highlighted the maturation of systems biology as applied to proteins.
Cytochrome c release from the mitochondria is a critical component of the apoptotic cell-death program. Cytochrome c–catalyzed peroxidation of cardiolipin, a mitochondrial phospholipid, has now been shown to lessen the binding of cytochrome c to the mitochondrial inner membrane and facilitate permeabilization of the outer membrane. These results describe a new and earlier pro-apoptotic role for cytochrome c.
Blocking gene expression by interfering with translation of mRNA can be accomplished by means of antisense or short interfering RNA strategies, but more potent inhibitors would act by inhibiting transcription of genomic DNA. Two new studies show efficient inhibition of transcription using single-stranded peptide nucleic acid or double-stranded RNA targeted to the open complex formed at the transcription start site.
Examples abound in nature in which organisms adapt and optimize their fitness in a given environment. A new study demonstrates that a cellular cost-benefit analysis drives growth optimization over the course of evolution by attenuation of protein expression levels.