Crystal structure of a far-red-sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism.

Cyanobacteriochromes (CBCRs) are small, linear tetrapyrrole (bilin)-binding photoreceptors in the phytochrome superfamily that regulate diverse light-mediated adaptive processes in cyanobacteria. More spectrally diverse than canonical red/far-red-sensing phytochromes, CBCRs were thought to be restricted to sensing visible and near UV light until recently when several subfamilies with far-red-sensing representatives (frCBCRs) were discovered. Two of these frCBCRs subfamilies have been shown to incorporate bilin precursors with larger pi-conjugated chromophores, while the third frCBCR subfamily uses the same phycocyanobilin precursor found in the bulk of the known CBCRs. To elucidate the molecular basis of far-red light perception by this third frCBCR subfamily, we determined the crystal structure of the far-red-absorbing dark state of one such frCBCR Anacy_2551g3 from Anabaena cylindrica PCC 7122 which exhibits a reversible far-red/orange photocycle. Determined by room temperature serial crystallography and cryocrystallography, the refined 2.7-Å structure reveals an unusual all-Z,syn configuration of the phycocyanobilin (PCB) chromophore that is considerably less extended than those of previously characterized red-light sensors in the phytochrome superfamily. Based on structural and spectroscopic comparisons with other bilin-binding proteins together with site-directed mutagenesis data, our studies reveal protein-chromophore interactions that are critical for the atypical bathochromic shift. Based on these analyses, we propose that far-red absorption in Anacy_2551g3 is the result of the additive effect of two distinct red-shift mechanisms involving cationic bilin lactim tautomers stabilized by a constrained all-Z,syn conformation and specific interactions with a highly conserved anionic residue.

Effects of therapeutic interventions on pain due to plantar fasciitis: A systematic review and meta-analysis.

OBJECTIVE: To determine the effects of different therapeutic interventions that have ever been evaluated in randomized controlled trials on pain due to plantar fasciitis. METHODS: We searched different electronic databases until September 2022. Mean differences (MDs) and 95% confidence intervals (CIs) were calculated. The Grading of Recommendations Assessment, Development and Evaluation was used to evaluate the overall certainty evidence. RESULTS: A total of 236 studies met the study criteria, including 15,401 patients. Botulinum toxin MD -2.14 (CI: -4.15, -0.14), micronized dehydrated human amnion/chorion membrane injection MD -3.31 (CI: -5.54, -1.08), dry needling MD -2.34 (CI: -4.64, -0.04), low-dye taping MD -3.60 (CI: -4.16, -3.03), low-level laser therapy MD -2.09 (CI: -2.28, -1.90), myofascial releases MD -1.79 (CI: -2.63, -0.94), platelet-rich plasma MD -2.40 (CI: -4.16, -0.63), radiofrequency MD -2.47 (CI: -4.65, -0.29), and stretching MD -1.14 (CI: -2.02, -0.26) resulted in being effective treatments for pain when compared to the control in the short term. In the medium and long term, only extracorporeal shock wave therapy MD -0.97 (CI: -1.13, -0.81)/MD -2.49 (CI: -3.17, -1.82) was effective for improving pain when compared to the control. CONCLUSIONS: Considering the available studies, this systematic review and meta-analysis showed that different therapeutic interventions seem to be useful strategies for improving pain in patients with plantar fasciitis. In the medium and long term, only extracorporeal shock wave therapy was effective in improving pain when compared to the control.

A far-red cyanobacteriochrome lineage specific for verdins.

Cyanobacteriochromes (CBCRs) are photoswitchable linear tetrapyrrole (bilin)-based light sensors in the phytochrome superfamily with a broad spectral range from the near UV through the far red (330 to 760 nm). The recent discovery of far-red absorbing CBCRs (frCBCRs) has garnered considerable interest from the optogenetic and imaging communities because of the deep penetrance of far-red light into mammalian tissue and the small size of the CBCR protein scaffold. The present studies were undertaken to determine the structural basis for far-red absorption by JSC1_58120g3, a frCBCR from the thermophilic cyanobacterium Leptolyngbya sp. JSC-1 that is a representative member of a phylogenetically distinct class. Unlike most CBCRs that bind phycocyanobilin (PCB), a phycobilin naturally occurring in cyanobacteria and only a few eukaryotic phototrophs, JSC1_58120g3's far-red absorption arises from incorporation of the PCB biosynthetic intermediate 181,182-dihydrobiliverdin (181,182-DHBV) rather than the more reduced and more abundant PCB. JSC1_58120g3 can also yield a far-red-absorbing adduct with the more widespread linear tetrapyrrole biliverdin IXα (BV), thus circumventing the need to coproduce or supplement optogenetic cell lines with PCB. Using high-resolution X-ray crystal structures of 181,182-DHBV and BV adducts of JSC1_58120g3 along with structure-guided mutagenesis, we have defined residues critical for its verdin-binding preference and far-red absorption. Far-red sensing and verdin incorporation make this frCBCR lineage an attractive template for developing robust optogenetic and imaging reagents for deep tissue applications.

Protein-chromophore interactions controlling photoisomerization in red/green cyanobacteriochromes.

Photoreceptors in the phytochrome superfamily use 15,16-photoisomerization of a linear tetrapyrrole (bilin) chromophore to photoconvert between two states with distinct spectral and biochemical properties. Canonical phytochromes include master regulators of plant growth and development in which light signals trigger interconversion between a red-absorbing 15Z dark-adapted state and a metastable, far-red-absorbing 15E photoproduct state. Distantly related cyanobacteriochromes (CBCRs) carry out a diverse range of photoregulatory functions in cyanobacteria and exhibit considerable spectral diversity. One widespread CBCR subfamily typically exhibits a red-absorbing 15Z dark-adapted state similar to that of phytochrome that gives rise to a distinct green-absorbing 15E photoproduct. This red/green CBCR subfamily also includes red-inactive examples that fail to undergo photoconversion, providing an opportunity to study protein-chromophore interactions that either promote photoisomerization or block it. In this work, we identified a conserved lineage of red-inactive CBCRs. This enabled us to identify three substitutions sufficient to block photoisomerization in photoactive red/green CBCRs. The resulting red-inactive variants faithfully replicated the fluorescence and circular dichroism properties of naturally occurring examples. Converse substitutions restored photoconversion in naturally red-inactive CBCRs. This work thus identifies protein-chromophore interactions that control the fate of the excited-state population in red/green cyanobacteriochromes.

I260Q DNA polymerase ß highlights precatalytic conformational rearrangements critical for fidelity.

DNA polymerase ß (pol ß) fills single nucleotide gaps in DNA during base excision repair and non-homologous end-joining. Pol ß must select the correct nucleotide from among a pool of four nucleotides with similar structures and properties in order to maintain genomic stability during DNA repair. Here, we use a combination of X-ray crystallography, fluorescence resonance energy transfer and nuclear magnetic resonance to show that pol ß's ability to access the appropriate conformations both before and upon binding to nucleotide substrates is integral to its fidelity. Importantly, we also demonstrate that the inability of the I260Q mutator variant of pol ß to properly navigate this conformational landscape results in error-prone DNA synthesis. Our work reveals that precatalytic conformational rearrangements themselves are an important underlying mechanism of substrate selection by DNA pol ß.

Cyanobacteriochrome-based photoswitchable adenylyl cyclases (cPACs) for broad spectrum light regulation of cAMP levels in cells.

Class III adenylyl cyclases generate the ubiquitous second messenger cAMP from ATP often in response to environmental or cellular cues. During evolution, soluble adenylyl cyclase catalytic domains have been repeatedly juxtaposed with signal-input domains to place cAMP synthesis under the control of a wide variety of these environmental and endogenous signals. Adenylyl cyclases with light-sensing domains have proliferated in photosynthetic species depending on light as an energy source, yet are also widespread in nonphotosynthetic species. Among such naturally occurring light sensors, several flavin-based photoactivated adenylyl cyclases (PACs) have been adopted as optogenetic tools to manipulate cellular processes with blue light. In this report, we report the discovery of a cyanobacteriochrome-based photoswitchable adenylyl cyclase (cPAC) from the cyanobacterium Microcoleus sp. PCC 7113. Unlike flavin-dependent PACs, which must thermally decay to be deactivated, cPAC exhibits a bistable photocycle whose adenylyl cyclase could be reversibly activated and inactivated by blue and green light, respectively. Through domain exchange experiments, we also document the ability to extend the wavelength-sensing specificity of cPAC into the near IR. In summary, our work has uncovered a cyanobacteriochrome-based adenylyl cyclase that holds great potential for the design of bistable photoswitchable adenylyl cyclases to fine-tune cAMP-regulated processes in cells, tissues, and whole organisms with light across the visible spectrum and into the near IR.

Discovery of Potent Glycosidases Enables Quantification of Smoke-Derived Phenolic Glycosides through Enzymatic Hydrolysis.

When grapes are exposed to wildfire smoke, certain smoke-related volatile phenols (VPs) can be absorbed into the fruit, where they can be then converted into volatile-phenol (VP) glycosides through glycosylation. These volatile-phenol glycosides can be particularly problematic from a winemaking standpoint as they can be hydrolyzed, releasing volatile phenols, which can contribute to smoke-related off-flavors. Current methods for quantitating these volatile-phenol glycosides present several challenges, including the requirement of expensive capital equipment, limited accuracy due to the molecular complexity of the glycosides, and the utilization of harsh reagents. To address these challenges, we proposed an enzymatic hydrolysis method enabled by a tailored enzyme cocktail of novel glycosidases discovered through genome mining, and the generated VPs from VP glycosides can be quantitated by gas chromatography-mass spectrometry (GC-MS). The enzyme cocktails displayed high activities and a broad substrate scope when using commercially available VP glycosides as the substrates for testing. When evaluated in an industrially relevant matrix of Cabernet Sauvignon wine and grapes, this enzymatic cocktail consistently achieved a comparable efficacy of acid hydrolysis. The proposed method offers a simple, safe, and affordable option for smoke taint analysis.

Effect of low-level laser therapy on pain and disability in patients with plantar fasciitis: A systematic review and meta-analysis.

OBJECTIVE: We performed a systematic review to investigate the effects of low-level laser therapy (LLLT) on pain and disability in patients with plantar fasciitis (PF). METHODS: We searched Pubmed, PEDro database, Scielo, and Cochrane Central for randomized controlled trials that evaluated the effects of LLLT for patients with PF. The methodological aspects of the studies included were scored using the PEDro scale. Three comparisons were made: LLLT compared with placebo, LLLT combined with conventional rehabilitation (CR) compared with CR and LLLT compared with extracorporeal shock wave therapy. RESULTS: Fourteen studies (817 patients) met the study criteria. Compared to the placebo group, LLLT improved pain (MD, -2.3; 95% CI: 2.6 to -2, I2 = 0%; 4 studies, N = 234: moderate-quality evidence) in the short term (0-6 weeks). No significant difference in short-term disability was found for participants in the LLLT group compared to the placebo group. Compared to the CR group, LLLT combined with CR improved pain (MD, -2.0; 95% CI: 2.9 to -1.1, I2 = 0%; 2 studies, N = 90: moderate-quality evidence) in the short term (0-6 weeks). Compared to extracorporeal shock wave therapy, LLLT did not significantly reduce pain intensity in the short term (MD, 0.5; 95% CI: 2.0 to 2.9, I2 = 96%; 4 studies, N = 175: low-quality evidence). CONCLUSIONS: LLLT may improve pain in the short term and can be considered as a component of care of patients with PF. However, this superiority disappeared compared to extracorporeal shock wave therapy. LEVEL OF EVIDENCE: Therapeutic level I.