HID-1 is required for sensing CO₂ level in the pharynx.

<p>(<b>A</b>) One-day-old adult <i>hid-1(yg316)</i> and N2 worms were exposed to 5%, 10%, or 20% CO₂ balanced with 21% O₂ and N₂. The pumping rate was measured under a dissecting microscope while the animals were exposed to the different gas mixtures. A gas mixture of 21% O₂ and 79% N₂ was used as a normal air control. (<b>B</b>) The inhibition of the pumping rate of the pharynx after exposure to high CO₂ level in <i>hid-1(yg316)</i> allele mutants is significantly reduced. Similarly, the inhibition of the pumping rate of the pharynx after exposure to high CO₂ level is reduced in other <i>hid-1</i> allele mutants (<i>sa772</i> and <i>sa1058</i>). Transgenic expression of HID-1 fused to eGFP in the <i>sa722</i> or <i>yg316</i> background (<i>hid-1(sa722</i>);HID-1::GFP or <i>hid-1(yg316)</i>;HID-1::GFP) is sufficient to restore the effect of high CO₂ level on the pumping rate back to the wild-type phenotype. In all experiments <i>N</i>≥30 animals. Different groups were compared by one-way ANOVA followed by <i>t</i> test. ***<i>P</i><.001. Error bars indicate SEM.</p

Reconstitution of isotopically labeled ribosomal protein L29 in the 50S large ribosomal subunit for solution-state and solid-state NMR.

Solid-state nuclear magnetic resonance (NMR) has recently emerged as a method of choice to study structural and dynamic properties of large biomolecular complexes at atomic resolution. Indeed, recent technological and methodological developments have enabled the study of ever more complex systems in the solid-state. However, to explore multicomponent protein complexes by NMR, specific labeling schemes need to be developed that are dependent on the biological question to be answered. We show here how to reconstitute an isotopically labeled protein within the unlabeled 50S or 70S ribosomal subunit. In particular, we focus on the 63-residue ribosomal protein L29 (~7&nbsp;kDa), which is located at the exit of the tunnel of the large 50S ribosomal subunit (~1.5&nbsp;MDa). The aim of this work is the preparation of a suitable sample to investigate allosteric conformational changes in a ribosomal protein that are induced by the nascent polypeptide chain and that trigger the interaction with different chaperones (e.g., trigger factor or SRP)