Temperature-sensitive gating of hCx26: high-resolution Raman spectroscopy sheds light on conformational changes

Abstract

The temperature-sensitive gating of human Connexin 26 (hCx26) was analyzed with confocal Raman microscopy. High-resolution Raman spectra covering the spectral range between 400 and 1500 rel. cm(-1) with a spectral resolution of 1 cm(-1) were fully annotated, revealing notable differences between the spectrum recorded from solubilized hCx26 in Ca(2+)-buffered POPC at 10°C and any other set of protein conditions (temperature, Ca(2+) presence, POPC presence). Spectral components originating from specific amino acids show that the TM1/EL1 parahelix and probably the TM4 trans-membrane helix and the plug domain are involved in the gating process responsible for fully closing the hemichannel.

Optical properties of the human round window membrane

“…Many biomolecules are probed at energy densities in the range from 0.7 to 46.1 MJ cm −2 (at λ ¼ 532 nm). 26,27 Note that for the energy densities applied in our setup, we did not observe any degradation of the RWMs via the confocal Raman microscope. When Raman spectra of molecules placed behind the membrane are to be recorded, the excitation light will be focused (if applicable) across that membrane so that the influence of the membrane on the Raman spectra is expected to be negligible.…”

Concurrent hyperbaric oxygen therapy and intratympanic steroid application as salvage therapy after severe sudden sensorineural hearing loss

“…Some of them are mechanosensitive and their state can be influenced, for example, by temperature. Kniggendorf et al . postulate that in lower temperature ranges, only small molecules can pass.…”

Raman Sensing and Its Multimodal Combination with Optoacoustics and OCT for Applications in the Life Sciences

“…As vibrational and rotational energy levels are highly specific for a certain molecule, Raman spectra are often referred to as molecular fingerprints. They can be used to analyze biological samples even at a functional level making use of intrinsic contrast alone and without the need for labeling [15,16,17,18,19]. If—owing to the composition of the sample or to technical tricks—only a single type of molecule is addressed, (resonance) Raman spectroscopy allows detailed analysis of the electronic, vibrational, and even rotational energy states of the molecule as well as its conformation [20,21,22,23].…”