Víctor A. Lórenz-Fonfría

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Methylation of lysine 4 (K4) within histone H3 has been linked to active transcription and is removed by LSD1 and the JmjC domain-containing proteins by amino-oxidation or hydroxylation, respectively. Here, we describe the deamination catalyzed by Lysyl oxidase-like 2 protein (LOXL2) as an unconventional chemical mechanism for H3K4 modification. Infrared(More)
Efficient retinal photoisomerization, signal transduction, and amplification contribute to single-photon electrical responses in vertebrates visual cells. However, spontaneous discrete electrical signals arising in the dark, with identical intensity and time profiles as those generated by genuine single photons (dark events), limit the potential capability(More)
The discovery of the light-gated ion channel channelrhodopsin (ChR) set the stage for the novel field of optogenetics, where cellular processes are controlled by light. However, the underlying molecular mechanism of light-induced cation permeation in ChR2 remains unknown. Here, we have traced the structural changes of ChR2 by time-resolved FTIR(More)
Vectorial transport by pumps requires a switch in the accessibility (or affinity) of the ion binding site from the extracelullar to the cytoplamic side, or vice versa. In the proton-pump bacteriorhodopsin (bR) the nature of this switch mechanism is still controversial, although it is expected to occur during the transition between two M substates. Here, we(More)
Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) is a light-activated cation channel, which is a promising optogenetic tool. We show by resonance Raman spectroscopy and retinal extraction followed by high pressure liquid chromatography (HPLC) that the isomeric ratio of all-trans to 13-cis of solubilized channelrhodopsin-1 is with 70:30 identical to(More)
Overlapped bands often appear in applications of infrared spectroscopy, for instance in the analysis of the amide I band of proteins. Fourier self-deconvolution (FSD) is a popular band-narrowing mathematical method, allowing for the resolution of overlapped bands. The filter function used in FSD plays a significant role in the factor by which the(More)
The behavior of the D115A mutant was analyzed by time-resolved UV-Vis and Fourier transformed infrared (FTIR) spectroscopies, aiming to clarify the role of Asp115 in the intra-protein signal transductions occurring during the bacteriorhodopsin photocycle. UV-Vis data on the D115A mutant show severely desynchronized photocycle kinetics. FTIR data show a poor(More)
We introduce a method for the estimation of the mean Lorentzian bandwidth of the component bands in a spectrum. The method is computationally simple, using only the module of the Fourier transform of the spectrum, and its first derivative. Moreover, the presented method does not require knowledge of the number of bands in the spectrum, their band positions,(More)
The melibiose carrier from Escherichia coli (MelB) couples the accumulation of the disaccharide melibiose to the downhill entry of H(+), Na(+), or Li(+). In this work, substrate-induced FTIR difference spectroscopy was used in combination with fluorescence spectroscopy to quantitatively compare the conformational properties of MelB mutants, implicated(More)
Attenuated total reflection infrared (ATR-IR) difference spectroscopy stands out because of its ability to provide information on the interaction of substrates with membrane proteins in their native lipid bilayer environment. We show how the study and interpretation of the structural changes in membrane proteins upon substrate binding is simplified by(More)