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Background and aims Obesity-induced pathogenesis of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is associated with increased de novo lipogenesis (DNL) and hepatic glucose production (HGP) that is due to excess fatty acids. Acyl-coenzyme A (CoA) thioesterase (Acot) family members control the cellular utilization of fatty acids by hydrolyzing (deactivating) acyl-CoA into nonesterified fatty acids and CoASH. Approach and results Using Caenorhabditis elegans, we identified Acot9 as the strongest regulator of lipid accumulation within the Acot family. Indicative of a maladaptive function, hepatic Acot9 expression was higher in patients with obesity who had NAFLD and NASH compared with healthy controls with obesity. In the setting of excessive nutrition, global ablation of Acot9 protected mice against increases in weight gain, HGP, steatosis, and steatohepatitis. Supportive of a hepatic function, the liver-specific deletion of Acot9 inhibited HGP and steatosis in mice without affecting diet-induced weight gain. By contrast, the rescue of Acot9 expression only in the livers of Acot9 knockout mice was sufficient to promote HGP and steatosis. Mechanistically, hepatic Acot9 localized to the inner mitochondrial membrane, where it deactivated short-chain but not long-chain fatty acyl-CoA. This unique localization and activity of Acot9 directed acetyl-CoA away from protein lysine acetylation and toward the citric acid (TCA) cycle. Acot9-mediated exacerbation of triglyceride and glucose biosynthesis was attributable at least in part to increased TCA cycle activity, which provided substrates for HGP and DNL. β-oxidation and ketone body production, which depend on long-chain fatty acyl-CoA, were not regulated by Acot9. Conclusions Taken together, our findings indicate that Acot9 channels hepatic acyl-CoAs toward increased HGP and DNL under the pathophysiology of obesity. Therefore, Acot9 represents a target for the management of NAFLD.

Existing drugs are slow to eradicate Mycobacterium tuberculosis (Mtb) in patients and have failed to control tuberculosis globally. One reason may be that host conditions impair Mtb’s replication, reducing its sensitivity to most antiinfectives. We devised a high-throughput screen for compounds that kill Mtb when its replication has been halted by reactive nitrogen intermediates (RNIs), acid, hypoxia, and a fatty acid carbon source. At concentrations routinely achieved in human blood, oxyphenbutazone (OPB), an inexpensive anti-inflammatory drug, was selectively mycobactericidal to nonreplicating (NR) Mtb. Its cidal activity depended on mild acid and was augmented by RNIs and fatty acid. Acid and RNIs fostered OPB’s 4-hydroxylation. The resultant 4-butyl-4-hydroxy-1-(4-hydroxyphenyl)-2-phenylpyrazolidine-3,5-dione (4-OH-OPB) killed both replicating and NR Mtb, including Mtb resistant to standard drugs. 4-OH-OPB depleted flavins and formed covalent adducts with N -acetyl-cysteine and mycothiol. 4-OH-OPB killed Mtb synergistically with oxidants and several antituberculosis drugs. Thus, conditions that block Mtb’s replication modify OPB and enhance its cidal action. Modified OPB kills both replicating and NR Mtb and sensitizes both to host-derived and medicinal antimycobacterial agents.

Oligomers of PNA:PNA duplexes with different amino acids appended to one strand of each duplex have been synthesized and studied for their chiral optical properties. The terminal amino acid is know...

There is growing appreciation of the functional relevance of unfolded proteins in biology. However, unfolded states of proteins have proven inaccessible to the usual techniques for high-resolution structural and energetic characterization. Unfolded states are still generally conceived of as statistical coils, based on the pioneering work of Flory [(1969) Statistical Mechanics of Chain Molecules (Wiley, New York)] and Tanford [(1968) Adv. Protein Chem. 23, 121–282]. Recently, several lines of independent evidence have raised doubts about the random coil model and offer support for alternative views. Here, we show that polyproline II conformation is dominant in a host–guest peptide model AcGGXGGNH 2 (X ≠ glycine), in equilibrium predominantly with β-structure. This result is inconsistent with a random coil model and the general view that these peptides are unstructured. By calculating a set of apparent Δ G values from the measured coupling constants of the backbone amides, we can construct a polyproline II scale that correlates negatively with β-sheet scales.

Spectroscopic evidence for the presence of local order in unfolded proteins, including polyproline II (PII) structure, now appears incontrovertible. The data supporting this order relies on analysis of short chain peptides. The dimensions of unfolded chains nevertheless conform to random coils. We have re-examined the dimensional properties of short chains using paramagnetic proton spin relaxation measurements to evaluate intermediate range distances (r) within alanine peptides linked to short proline arms.(1) Two peptides were employed in our studies,, OO-T∗-PPPA∗PPPA∗-OO and OO-T∗-PPPAAAA∗-OO, where O is Ornithine, T∗ is Toac (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), A∗ is 15N labelled alanine. Mesostate based Monte-Carlo sampling calculations (2) were carried out to interpret the relaxation data. The conclusion of the study is that over 90% occupation of extended conformations, i.e. PII and β mesostates, is required to reproduce the experimentally observed distance averaging. Compact structures including αR, αL and turns are clearly present but are not dominant in the conformational ensemble. Analysis of the conformation of other side chains will be presented.(1) Chen, K et al. Ang. Chem. Int. Ed. 2007 46, 9036.(2) Gong, H, Fleming, PH, Rose, GD. Proc. Natl. Acad. Sci. USA 2005, 102, 16227.