Intracellular microbial rhodopsin-based optogenetics to control metabolism and cell signaling.

Microbial rhodopsin (MRs) ion channels and pumps have become invaluable optogenetic tools for neuroscience as well as biomedical applications. Recently, MR-optogenetics expanded towards subcellular organelles opening principally new opportunities in optogenetic control of intracellular metabolism and signaling precise manipulations of organelle ion gradients using light. This new optogenetic field expands the opportunities for basic and medical studies of cancer, cardiovascular, and metabolic disorders, providing more detailed and accurate control of cell physiology.

Chaotic aging: intrinsically disordered proteins in aging-related processes.

The development of aging is associated with the disruption of key cellular processes manifested as well-established hallmarks of aging. Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) have no stable tertiary structure that provide them a power to be configurable hubs in signaling cascades and regulate many processes, potentially including those related to aging. There is a need to clarify the roles of IDPs/IDRs in aging.

I-Shaped Dimers of a Plant Chloroplast FF-ATP Synthase in Response to Changes in Ionic Strength.

F-type ATP synthases play a key role in oxidative and photophosphorylation processes generating adenosine triphosphate (ATP) for most biochemical reactions in living organisms. In contrast to the mitochondrial FF-ATP synthases, those of chloroplasts are known to be mostly monomers with approx. 15% fraction of oligomers interacting presumably non-specifically in a thylakoid membrane.

Structure-based insights into evolution of rhodopsins.

Rhodopsins, most of which are proton pumps generating transmembrane electrochemical proton gradients, span all three domains of life, are abundant in the biosphere, and could play a crucial role in the early evolution of life on earth. Whereas archaeal and bacterial proton pumps are among the best structurally characterized proteins, rhodopsins from unicellular eukaryotes have not been well characterized. To fill this gap in the current understanding of the proton pumps and to gain insight into the evolution of rhodopsins using a structure-based approach, we performed a structural and functional analysis of the light-driven proton pump LR (Mac) from the pathogenic fungus Leptosphaeria maculans.

Molecular mechanism of light-driven sodium pumping.

The light-driven sodium-pumping rhodopsin KR2 from Krokinobacter eikastus is the only non-proton cation active transporter with demonstrated potential for optogenetics. However, the existing structural data on KR2 correspond exclusively to its ground state, and show no sodium inside the protein, which hampers the understanding of sodium-pumping mechanism. Here we present crystal structure of the O-intermediate of the physiologically relevant pentameric form of KR2 at the resolution of 2.

Chemically Stable Lipids for Membrane Protein Crystallization.

Lipidic cubic phase (LCP) has been widely recognized as a promising membrane-mimicking matrix for biophysical studies of membrane proteins and their crystallization in a lipidic environment. Application of this material to a wide variety of membrane proteins, however, is hindered due to a limited number of available host lipids, mostly monoacylglycerols (MAGs). Here, we designed, synthesized and characterized a series of chemically stable lipids resistant to hydrolysis, with properties complementary to the widely used MAGs.

Highly Sensitive Coherent Anti-Stokes Raman Scattering Imaging of Protein Crystals.

Serial crystallography at last generation X-ray synchrotron sources and free electron lasers enabled data collection with micrometer and even submicrometer size crystals, which have resulted in amazing progress in structural biology. However, imaging of small crystals, which although is highly demanded, remains a challenge, especially in the case of membrane protein crystals. Here we describe a new extremely sensitive method of the imaging of protein crystals that is based on coherent anti-Stokes Raman scattering.