A Study on the Development of Information and Communication Technology-Based Oral Functional Rehabilitation Exercise Program Content for Elderly People.

Background/Objectives: This study was conducted to develop information and communication technology (ICT)-based oral functional rehabilitation exercise (OFRE) program content to effectively improve the oral function of the elderly people. Methods: After selecting evidence-based effective OFRE items through systematic review, the final items were constructed through the validity evaluation of detailed items through an expert Delphi survey. The items were composed in a simple content form that can be performed directly and applied to ICT-based mobile applications. Results: The final content items consisted of an oral functional motor-ability measurement, oral Pilates videos, and games. The first is to measure the maximum opening amount before and after exercise, and the opening amount was designed to be measured by eating the fruit displayed on the screen by opening and closing the lips. The second one consisted of eight exercises in the video, and each exercise was to be performed at least three times a day, with a total of two sets. The third is a salivary secretion function exercise that stimulates the salivary glands to stimulate the user's interest and enable them to perform oral movements on their own. It consists of a lip and respiratory muscle exercise that inflates the cheeks and bursts a balloon, and the image disappears when the word in the image presented on the screen is pronounced correctly. It consists of pronunciation exercises. Conclusions: This content development attempt can be expanded into new convergence research linked to ICT and can be used as basic data when developing related content as part of digital care for the elderly in the future.

C-ter100 peptide derived from Vibrio vEP-45 protease acts as a pathogen-associated molecular pattern to induce inflammation and innate immunity.

The bacterium Vibrio vulnificus causes fatal septicemia in humans. Previously, we reported that an extracellular metalloprotease, vEP-45, secreted by V. vulnificus, undergoes self-proteolysis to generate a 34 kDa protease (vEP-34) by losing its C-terminal domain to produce the C-ter100 peptide. Moreover, we revealed that vEP-45 and vEP-34 proteases induce blood coagulation and activate the kallikrein/kinin system. However, the role of the C-ter100 peptide fragment released from vEP-45 in inducing inflammation is still unclear. Here, we elucidate, for the first time, the effects of C-ter100 on inducing inflammation and activating host innate immunity. Our results showed that C-ter100 could activate NF-κB by binding to the receptor TLR4, thereby promoting the secretion of inflammatory cytokines and molecules, such as TNF-α and nitric oxide (NO). Furthermore, C-ter100 could prime and activate the NLRP3 inflammasome (NLRP3, ASC, and caspase 1), causing IL-1ß secretion. In mice, C-ter100 induced the recruitment of immune cells, such as neutrophils and monocytes, along with histamine release into the plasma. Furthermore, the inflammatory response induced by C-ter100 could be effectively neutralized by an anti-C-ter100 monoclonal antibody (C-ter100Mab). These results demonstrate that C-ter100 can be a pathogen-associated molecular pattern (PAMP) that activates an innate immune response during Vibrio infection and could be a target for the development of antibiotics.

Validation of the conceptual framework and intervention scope of oral function rehabilitation exercise.

OBJECTIVES: This study used a Delphi survey to define the concept of oral function rehabilitation exercise (OFRE) based on the International Classification of Functioning, Disability, and Health (ICF) and to categorise intervention domains for community-dwelling older adults. BACKGROUND: While numerous studies have been conducted to improve oral function through exercise interventions, the conceptual definition of oral exercise remains unclear and there is a lack of systematic categorisation of oral exercise intervention domains. METHODS: A preliminary model was developed based on the key findings of 19 papers selected from a prior systematic review. Its validity was confirmed through a Delphi survey conducted twice with eight expert panellists. Consensus was achieved by evaluating the validity of the OFRE conceptual framework, the accuracy of OFRE conceptual definitions, and intervention domains. RESULTS: Through expert consensus, an ICF-based OFRE conceptual framework was developed that includes 21 factors that affect the oral health status of the older adults. The OFRE intervention domain for improving the health status consisted of oral function rehabilitation warm-up exercise, masticatory function exercise, swallowing function exercise, articulatory function exercise, salivary function exercise, and oral function rehabilitation cool-down exercise, and 11 specific intervention methods were derived. CONCLUSIONS: The OFRE intervention can be used for planning and applying successful interventions to improve oral function and life function of older adults.

Everolimus exerts anticancer effects through inhibiting the interaction of matrix metalloproteinase-7 with syndecan-2 in colon cancer cells.

Previous work showed that matrix metalloproteinase-7 (MMP-7) regulates colon cancer activities through an interaction with syndecan-2 (SDC-2) and SDC-2-derived peptide that disrupts this interaction and exhibits anticancer activity in colon cancer. Here, to identify potential anticancer agents, a library of 1,379 Food and Drug Administration (FDA)-approved drugs that interact with the MMP-7 prodomain were virtually screened by protein-ligand docking score analysis using the GalaxyDock3 program. Among five candidates selected based on their structures and total energy values for interacting with the MMP-7 prodomain, the known mechanistic target of rapamycin kinase (mTOR) inhibitor, everolimus, showed the highest binding affinity and the strongest ability to disrupt the interaction of the MMP-7 prodomain with the SDC-2 extracellular domain in vitro. Everolimus treatment of the HCT116 human colon cancer cell line did not affect the mRNA expression levels of MMP-7 and SDC-2 but reduced the adhesion of cells to MMP-7 prodomain-coated plates and the cell-surface localization of MMP-7. Thus, everolimus appears to inhibit the interaction between MMP-7 and SDC-2. Everolimus treatment of HCT116 cells also reduced their gelatin-degradation activity and anticancer activities, including colony formation. Interestingly, cells treated with sirolimus, another mTOR inhibitor, triggered less gelatin-degradation activity, suggesting that this inhibitory effect of everolimus was not due to inhibition of the mTOR pathway. Consistently, everolimus inhibited the colony-forming ability of mTOR-resistant HT29 cells. Together, these data suggest that, in addition to inhibiting mTOR signaling, everolimus exerts anticancer activity by interfering with the interaction of MMP-7 and SDC-2, and could be a useful therapeutic anticancer drug for colon cancer.NEW & NOTEWORTHY The utility of cancer therapeutics targeting the proteolytic activities of MMPs is limited because MMPs are widely distributed throughout the body and involved in many different aspects of cell functions. This work specifically targets the activation of MMP-7 through its interaction with syndecan-2. Notably, everolimus, a known mTOR inhibitor, blocked this interaction, demonstrating a novel role for everolimus in inhibiting mTOR signaling and impairing the interaction of MMP-7 with syndecan-2 in colon cancer.

Structure of the human galanin receptor 2 bound to galanin and Gq reveals the basis of ligand specificity and how binding affects the G-protein interface.

Galanin is a neuropeptide expressed in the central and peripheral nervous systems, where it regulates various processes including neuroendocrine release, cognition, and nerve regeneration. Three G-protein coupled receptors (GPCRs) for galanin have been discovered, which is the focus of efforts to treat diseases including Alzheimer's disease, anxiety, and addiction. To understand the basis of the ligand preferences of the receptors and to assist structure-based drug design, we used cryo-electron microscopy (cryo-EM) to solve the molecular structure of GALR2 bound to galanin and a cognate heterotrimeric G-protein, providing a molecular view of the neuropeptide binding site. Mutant proteins were assayed to help reveal the basis of ligand specificity, and structural comparison between the activated GALR2 and inactive hß2AR was used to relate galanin binding to the movements of transmembrane (TM) helices and the G-protein interface.

Substituted Syndecan-2-Derived Mimetic Peptides Show Improved Antitumor Activity over the Parent Syndecan-2-Derived Peptide.

We previously showed that a synthetic peptide (S2-P) corresponding to a portion of the human syndecan-2 (SDC2) sequence can bind to the pro-domain of matrix metalloproteinase-7 (MMP-7) to inhibit colon cancer activities. Since S2-P had a relatively weak binding affinity for the MMP-7 pro-domain, we herein modified the amino acid sequence of S2-P to improve the anticancer potential. On the basis of the interaction structure of S2-P and MMP-7, four peptides were generated by replacing amino acids near Tyr 51, which is critical for the interaction. The SDC2-mimetic peptides harboring an Ala-to-Asp substitution at the C-terminal side of Tyr 51 (S2-D) or with an Ala-to-Phe substitution at the N-terminal side of Tyr 51 and an Ala-to-Asp substitution at the C-terminal side of Tyr 51 (S2-FE) showed improved interaction affinities for the MMP-7 pro-domain. Compared to S2-P, S2-FE was better able to inhibit the SDC2-MMP-7 interaction, the cell surface localization of MMP-7, the gelatin degradation activity of MMP-7, and the cancer activities (cell migration, invasion, and colony-forming activity) of human HCT116 colon cancer cells in vitro. In vivo, S2-FE inhibited the primary tumor growth and lung metastasis of CT26 mouse colon cancer cells in a xenograft mouse model. Together, these data suggest that S2-FE could be useful therapeutic anticancer peptides for colon cancer.

Structural insights into the HBV receptor and bile acid transporter NTCP.

Around 250 million people are infected with hepatitis B virus (HBV) worldwide1, and 15 million may also carry the satellite virus hepatitis D virus (HDV), which confers even greater risk of severe liver disease2. The HBV receptor has been identified as sodium taurocholate co-transporting polypeptide (NTCP), which interacts directly with the first 48 amino acid residues of the N-myristoylated N-terminal preS1 domain of the viral large protein3. Despite the pressing need for therapeutic agents to counter HBV, the structure of NTCP remains unsolved. This 349-residue protein is closely related to human apical sodium-dependent bile acid transporter (ASBT), another member of the solute carrier family SLC10. Crystal structures have been reported of similar bile acid transporters from bacteria4,5, and these models are believed to resemble closely both NTCP and ASBT. Here we have used cryo-electron microscopy to solve the structure of NTCP bound to an antibody, clearly showing that the transporter has no equivalent of the first transmembrane helix found in other SLC10 proteins, and that the N terminus is exposed on the extracellular face. Comparison of our structure with those of related proteins indicates a common mechanism of bile acid transport, but the NTCP structure displays an additional pocket formed by residues that are known to interact with preS1, presenting new opportunities for structure-based drug design.

Cryo-EM structure of the human somatostatin receptor 2 complex with its agonist somatostatin delineates the ligand-binding specificity.

Somatostatin is a peptide hormone that regulates endocrine systems by binding to G-protein-coupled somatostatin receptors. Somatostatin receptor 2 (SSTR2) is a human somatostatin receptor and is highly implicated in hormone disorders, cancers, and neurological diseases. Here, we report the high-resolution cryo-EM structure of full-length human SSTR2 bound to the agonist somatostatin (SST-14) in complex with inhibitory G (Gi) proteins. Our structural and mutagenesis analyses show that seven transmembrane helices form a deep pocket for ligand binding and that SSTR2 recognizes the highly conserved Trp-Lys motif of SST-14 at the bottom of the pocket. Furthermore, our sequence analysis combined with AlphaFold modeled structures of other SSTR isoforms provide a structural basis for the mechanism by which SSTR family proteins specifically interact with their cognate ligands. This work provides the first glimpse into the molecular recognition mechanism of somatostatin receptors and a crucial resource to develop therapeutics targeting somatostatin receptors.

Structural and functional identification of the uncharacterized metallo-ß-lactamase superfamily protein TW9814 as a phosphodiesterase with unique metal coordination.

Metallo-ß-lactamase (MBL) superfamily proteins have a common αß/ßα sandwich fold and perform a variety of functions through metal-mediated catalysis. However, because of the enormous scale of this superfamily, only a small percentage of the proteins belonging to the superfamily have been annotated structurally or functionally to date. Therefore, much remains unknown about the MBL superfamily proteins. Here, TW9814, a hypothetical MBL superfamily protein, was structurally and functionally investigated. Guided by the crystal structure of dimeric TW9814, it was demonstrated that TW9814 functions as a phosphodiesterase (PDE) in the presence of divalent metal ions such as manganese(II) or nickel(II). A docking model between TW9814 and the substrate bis(p-nitrophenyl)phosphate (bpNPP) showed the importance of the dimerization of TW9814 for its bpNPP-hydrolyzing activity and for the interaction between the enzyme and the substrate. TW9814 showed outstanding catalytic efficiency (kcat/Km) under alkaline conditions compared with other PDEs. The activity of TW9814 appears to be regulated through a disulfide bond, which is a feature that is not present in other MBL superfamily members. This study provides a platform for the functional characterization of other hypothetical proteins of the MBL or other superfamilies.

Crystal Structures of the Plant Phospholipase A1 Proteins Reveal a Unique Dimerization Domain.

Phospholipase is an enzyme that hydrolyzes various phospholipid substrates at specific ester bonds and plays important roles such as membrane remodeling, as digestive enzymes, and the regulation of cellular mechanism. Phospholipase proteins are divided into following the four major groups according to the ester bonds they cleave off: phospholipase A1 (PLA1), phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Among the four phospholipase groups, PLA1 has been less studied than the other phospholipases. Here, we report the first molecular structures of plant PLA1s: AtDSEL and CaPLA1 derived from Arabidopsis thaliana and Capsicum annuum, respectively. AtDSEL and CaPLA1 are novel PLA1s in that they form homodimers since PLAs are generally in the form of a monomer. The dimerization domain at the C-terminal of the AtDSEL and CaPLA1 makes hydrophobic interactions between each monomer, respectively. The C-terminal domain is also present in PLA1s of other plants, but not in PLAs of mammals and fungi. An activity assay of AtDSEL toward various lipid substrates demonstrates that AtDSEL is specialized for the cleavage of sn-1 acyl chains. This report reveals a new domain that exists only in plant PLA1s and suggests that the domain is essential for homodimerization.

Development of Guidelines on the Primary Prevention of Frailty in Community-Dwelling Older Adults.

BACKGROUND: Despite the increasing number of older adults as the population ages, there is a lack of frailty prevention guidelines for community-dwelling older adults. The Korean Frailty and Aging Cohort Study conducted systematic review on contributors to frailty and developed guidelines on the primary prevention of frailty in community-dwelling older adults. METHODS: This study updated a previous systematic review of contributors to frailty by adding the most recent articles. Based on this updated systematic review, experts in geriatrics and gerontology developed guidelines for preventing frailty using the Delphi method. RESULTS: These guidelines categorized the recommendations into physical activity, resilience, oral health, management of non-communicable diseases, involvement in society, smoking cessation, and eating various kinds of food. CONCLUSION: Unlike previous frailty-related guidelines, this study developed evidence-based frailty prevention guidelines based on a systematic review. The guidelines are expected to contribute to the healthy aging of community-dwelling older adults by the primary prevention of frailty.

Structural and Functional Characterizations of Cancer Targeting Nanoparticles Based on Hepatitis B Virus Capsid.

Cancer targeting nanoparticles have been extensively studied, but stable and applicable agents have yet to be developed. Here, we report stable nanoparticles based on hepatitis B core antigen (HBcAg) for cancer therapy. HBcAg monomers assemble into spherical capsids of 180 or 240 subunits. HBcAg was engineered to present an affibody for binding to human epidermal growth factor receptor 1 (EGFR) and to present histidine and tyrosine tags for binding to gold ions. The HBcAg engineered to present affibody and tags (HAF) bound specifically to EGFR and exterminated the EGFR-overexpressing adenocarcinomas under alternating magnetic field (AMF) after binding with gold ions. Using cryogenic electron microscopy (cryo-EM), we obtained the molecular structures of recombinant HAF and found that the overall structure of HAF was the same as that of HBcAg, except with the affibody on the spike. Therefore, HAF is viable for cancer therapy with the advantage of maintaining a stable capsid form. If the affibody in HAF is replaced with a specific sequence to bind to another targetable disease protein, the nanoparticles can be used for drug development over a wide spectrum.

Solution structure of the Myb domain of Terfa derived from Zebrafish interacting with both human and plant telomeric DNA.

Telomeric repeat binding factor a (Terfa) derived from zebrafish is a homologous protein with human telomeric repeat binding factor 2 (TRF2). Terfa is known as a senescence-associated biomarker in various research through the zebrafish animal model. In addition, according to the findings so far, it has been confirmed that human or plant telomere binding proteins bind to telomeric DNA specialized for each species, but, in our result, Terfa shows it strongly binds to both human or plant type telomeric DNA. Here we characterized the DNA binding properties and demonstrate the solution structure of Terfa and identified residues participating in the interaction with both human and plant telomeric DNA. In DNA recognition of human and plant telomere binding proteins, the N-terminal loop and the α-helix 3 part of Myb domain were bound majorly, whereas, in the case of Terfa, the N-terminal loop, the α-helix 1-2 loop, and α-helix 2 of the Myb domain were dominantly bound. Therefore, when Terfa recognizes DNA, it was found that the binding module differs from previously known telomere binding proteins. The comparison of the structure of the telomere binding proteins provides an opportunity to understand more specifically how the structural properties of each telomere binding protein are associated with telomeric DNA binding from an evolutionary point of view.

Dietary Patterns and Frailty in Older Korean Adults: Results from the Korean Frailty and Aging Cohort Study.

There are few studies on dietary patterns and frailty in Asians, and the results are controversial. Therefore, this study examined the association between dietary patterns and frailty in older Korean adults using the Korean Frailty and Aging Cohort Study (KFACS). The sample consisted of 511 subjects, aged 70-84 years, community-dwelling older people from the KFACS. Dietary data were obtained from the baseline study (2016-2017) using two nonconsecutive 24-h dietary recalls, and dietary patterns were extracted using reduced rank regression. Frailty was measured by a modified version of the Fried Frailty Phenotype (FFP) in both the baseline (2016) and the first follow-up study (2018). A logistic regression analysis was used to examine the association between dietary patterns and frailty status in 2018. The "meat, fish, and vegetables" pattern was inversely associated with pre-frailty (OR = 0.41, 95% CI = 0.21-0.81, p for trend = 0.009) and exhaustion (OR = 0.41, 95% CI = 0.20-0.85, p for trend = 0.020). The "milk" pattern was not significantly associated with frailty status or the FFP components. In conclusion, a dietary pattern with a high consumption of meat, fish, and vegetables was associated with a lower likelihood of pre-frailty.

Early-stage dynamics of chloride ion-pumping rhodopsin revealed by a femtosecond X-ray laser.

Chloride ion-pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl- into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation-diffusion process upon light-triggered retinal isomerization.

NMR spectroscopy uncovers direct interaction between BAF60A and p53.

The BRG1-associated factor 60A (BAF60A), an SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily D member 1, has been known to be important for transcriptional activation and inhibition through the alteration of the DNA nucleosome. Although the association between BAF60A and p53 plays a critical role in tumor suppression, the interaction mode is still unclear. Here, we report the detailed interactions between BAF60A and p53 by both NMR spectroscopy and pull-down analysis. Both N-terminal region (BAF60ANR) and the SWIB domain (BAF60ASWIB) of BAF60A directly interact with the tetramerization domain of p53 (p53TET). NMR data show that Ile315, Met366, Ala388, and Tyr390 of BAF60ASWIB are mostly involved in p53TET binding. The calculated dissociation constant (KD) value between BAF60ASWIB and p53TET revealed relatively weak binding affinity, at approximately 0.3 ± 0.065 mM. Our data will enhance detailed interaction mechanism to elucidate the molecular basis of p53-mediated integration via BAF60A interaction.

Crystal structure of the HMG domain of human BAF57 and its interaction with four-way junction DNA.

The SWI/SNF chromatin remodeling complex plays important roles in gene regulation and it is classified as the SWI/SNF complex in yeast and BAF complex in vertebrates. BAF57, one of the subunits that forms the chromatin remodeling complex core, is well conserved in the BAF complex of vertebrates, which is replaced by bap111 in the Drosophila BAP complex and does not have a counterpart in the yeast SWI/SNF complex. This suggests that BAF57 is a key component of the chromatin remodeling complex in higher eukaryotes. BAF57 contains a HMG domain, which is widely distributed among various proteins and functions as a DNA binding motif. Most proteins with HMG domain bind to four-way junction (4WJ) DNA. Here, we report the crystal structure of the HMG domain of BAF57 (BAF57HMG) at a resolution of 2.55 Å. The structure consists of three α-helices and adopts an L-shaped form. The overall structure is stabilized by a hydrophobic core, which is formed by hydrophobic residues. The binding affinity between BAF57HMG and 4WJ DNA is determined as a 295.83 ± 1.05 nM using a fluorescence quenching assay, and the structure revealed 4WJ DNA binding site of BAF57HMG. Our data will serve structural basis in understanding the roles of BAF57 during chromatin remodeling process.

Structural modification of NADPH oxidase activator (Noxa 1) by oxidative stress: An experimental and computational study.

NADPH oxidases 1 (NOX1) derived reactive oxygen species (ROS) play an important role in the progression of cancer through signaling pathways. Therefore, in this paper, we demonstrate the effect of cold atmospheric plasma (CAP) on the structural changes of Noxa1 SH3 protein, one of the regulatory subunits of NOX1. For this purpose, firstly we purified the Noxa1 SH3 protein and analyzed the structure using X-ray crystallography, and subsequently, we treated the protein with two types of CAP reactors such as pulsed dielectric barrier discharge (DBD) and Soft Jet for different time intervals. The structural deformation of Noxa1 SH3 protein was analyzed by various experimental methods (circular dichroism, fluorescence, and NMR spectroscopy) and by MD simulations. Additionally, we demonstrate the effect of CAP (DBD and Soft Jet) on the viability and expression of NOX1 in A375 cancer cells. Our results are useful to understand the structural modification/oxidation occur in protein due to reactive oxygen and nitrogen (RONS) species generated by CAP.

Relationships between cognitive function and frailty in older Korean adults: The moderating effect of the number of teeth.

BACKGROUND: Cognitive function and physical frailty are known to be closely related. Among older adults with dementia, those who wear dentures have a higher mortality rate than those who do not wear them. This suggests the possibility that oral health may affect the cognitive-frailty relationship. This study aims to investigate whether the number of teeth present, acts as a moderating variable in the cognitive function-frailty relationship. METHODS: Data were obtained from the cross-sectional baseline study of the Korean Frailty Aging Cohort Study (2016-2017). Cognitive function was assessed using the Mini-Mental State Examination. Frailty score was based on the Cardiovascular Health Study Index. Oral condition was evaluated by the number of teeth present and analyzed using categories of 0-9 teeth, 10-19 teeth, and ≥20. The moderation effect was analyzed using the ordinary least squares (OLS) regression. RESULTS: Data on 2,310 older adults (1,110 men; mean age 75.9 ± 3.9 years) was analyzed. Adjusting for age, sex, income, education, alcohol drinking, body mass index, and number of comorbidities, cognitive function and frailty showed a negative association (B=-.030, p = .011). In the 10-19 teeth category, compared to the 0-9 teeth category, a negative association with frailty was found (B=-.152, p = .026). A significant interaction effect between the number of teeth and cognitive function was detected (p = .007). CONCLUSION: The number of teeth may modify the degree of the association between cognitive function and frailty. For effective frailty management of older persons, cognitive function management and oral management should be considered and performed together.

Structure-Based Functional Modification Study of a Cyanobacterial Chloride Pump for Transporting Multiple Anions.

Understanding the structure and functional mechanisms of cyanobacterial halorhodopsin has become increasingly important, given the report that Synechocystis halorhodopsin (SyHR), a homolog of the cyanobacterial halorhodopsin from Mastigocladopsis repens (MrHR), can take up divalent ions, such as SO42-, as well as chloride ions. Here, the crystal structure of MrHR, containing a unique "TSD" chloride ion conduction motif, was determined as a homotrimer at a resolution of 1.9 Å. The detailed structure of MrHR revealed a unique trimeric topology of the light-driven chloride pump, with peculiar coordination of two water molecules and hydrogen-mediated bonds near the TSD motif, as well as a short B-C loop. Structural and functional analyses of MrHR revealed key residues responsible for the anion selectivity of cyanobacterial halorhodopsin and the involvement of two chloride ion-binding sites in the ion conduction pathway. Alanine mutant of Asn63, Pro118, and Glu182 locating in the anion inlet induce multifunctional uptake of chloride, nitrate, and sulfate ions. Moreover, the structure of N63A/P118A provides information on how SyHR promotes divalent ion transport. Our findings significantly advance the structural understanding of microbial rhodopsins with different motifs. They also provide insight into the general structural framework underlying the molecular mechanisms of the cyanobacterial chloride pump containing SyHR, the only molecule known to transport both sulfate and chloride ions.