Identification of the basic amino acid residues on the PsbP protein involved in the electrostatic interaction with photosystem II

AbstractThe PsbP protein is an extrinsic subunit of photosystem II (PSII) that is essential for photoautotrophic growth in higher plants. Several crystal structures of PsbP have been reported, but the binding topology of PsbP in PSII has not yet been clarified. In this study, we report that the basic pocket of PsbP, which consists of conserved Arg48, Lys143, and Lys160, is important for the electrostatic interaction with the PSII complex. Our release-reconstitution experiment showed that the binding affinities of PsbP-R48A, -K143A, and -K160A mutated proteins to PSII were lower than that of PsbP-WT, and triple mutations of these residues greatly diminished the binding affinity to PSII. Even when maximum possible binding had occurred, the R48A, K143A, and K160A proteins showed a reduced ability to restore the rate of oxygen evolution at low chloride concentrations. Fourier transform infrared resonance (FTIR) difference spectroscopy results were consistent with the above finding, and suggested that these mutated proteins were not able to induce the normal conformational change around the Mn cluster during S1 to S2 transition. Finally, chemical cross-linking experiments suggested that the interaction between the N-terminus of PsbP with PsbE was inhibited by these mutations. These data suggest that the basic pocket of PsbP is important for proper association and interaction with PSII. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy

D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion

植物の光合成初期過程の酸素発生活性を向上させるアミノ酸変異を発見 --光合成・人工光合成の光エネルギー変換効率の向上へ期待--. 京都大学プレスリリース. 2022-08-18.Photosystem II (PSII) is a multi-subunit membrane protein complex that catalyzes light-driven oxidation of water to molecular oxygen. The chloride ion (Cl−) has long been known as an essential cofactor for oxygen evolution by PSII, and two Cl− ions (Cl-1 and Cl-2) have been found to specifically bind near the Mn4CaO5 cluster within the oxygen-evolving center (OEC). However, despite intensive studies on these Cl− ions, little is known about the function of Cl-2, the Cl− ion that is associated with the backbone nitrogens of D1-Asn338, D1-Phe339, and CP43-Glu354. In green plant PSII, the membrane extrinsic subunits—PsbP and PsbQ—are responsible for Cl− retention within the OEC. The Loop 4 region of PsbP, consisting of highly conserved residues Thr135–Gly142, is inserted close to Cl-2, but its importance has not been examined to date. Here, we investigated the importance of PsbP-Loop 4 using spinach PSII membranes reconstituted with spinach PsbP proteins harboring mutations in this region. Mutations in PsbP-Loop 4 had remarkable effects on the rate of oxygen evolution by PSII. Moreover, we found that a specific mutation, PsbP-D139N, significantly enhanced the oxygen-evolving activity in the absence of PsbQ, but not significantly in its presence. The D139N mutation increased the Cl− retention ability of PsbP and induced a unique structural change in the OEC, as indicated by light-induced Fourier transform infrared (FTIR) difference spectroscopy and theoretical calculations. Our findings provide insight into the functional significance of Cl-2 in the water-oxidizing reaction of PSII

GPS and chemotherapy for elderly NSCLC

Background : Although platinum-combination chemotherapy is widely used to treat advanced non-small cell lung cancer (NSCLC), not all elderly patients benefit from this regimen. In this retrospective study, we aimed to evaluate whether the Glasgow Prognostic Score (GPS), an indicator of systemic inflammation and malnutrition, could predict the tolerability and efficacy of platinum-combination chemotherapy among elderly patients with NSCLC. Methods : The eligibility criteria included patients aged ≥ 70 years with NSCLC treated with first-line platinum-combination chemotherapy at Shimane University Hospital between January 2015 and December 2018. Results : Thirty-two patients with NSCLC (median age, 74 years) were included. The GPS scores were 0–1 for 19 patients and 2 for 13 patients. Four chemotherapy cycles were completed by 57.9% and 30.8% of patients in the GPS 0–1 and GPS 2 groups, respectively. The GPS 0–1 group experienced better outcomes than the GPS 2 group (response rate : 26% vs. 15%, P = 0.67 ; median progression-free survival : 4.1 vs. 2.1 months, P = 0.0026 ; median overall survival : 22.8 vs. 9.6 months, P = 0.0092). Conclusions : Platinum-combination chemotherapy demonstrated promising efficacy among elderly NSCLC patients with a GPS 0–1. Therefore, GPS may be crucial in determining whether treatments recommended for younger patients are suitable for older patients with NSCLC

Frail patients with respiratory failure

Background : Older patients with severe respiratory failure have higher mortality rates and are more likely to experience impairments in activities of daily living (ADL). Methods : We retrospectively reviewed patients (≥ 75 years) who received intubation and artificial ventilation for respiratory failure at Shimane University Hospital between November 2014 and December 2020. We compared the outcomes of frail patients with those of self-sufficient patients. Results : Thirty-two patients were included. ADL ability before respiratory failure was rated self-sufficient in 18 patients (self-sufficient group) and not self-sufficient in 14 patients (frail group). None of the patients in either group underwent advanced care planning prior to the onset of respiratory failure. In the self-sufficient and frail groups, the in-hospital mortality rates were 33% and 50%, and the incidence of bedridden patients at discharge was 6% and 43%, respectively. Most patients in the frail group (93%) died or were bedridden. The median hospitalization cost was JPY 2,984,000 for the self-sufficient group and JPY 3,008,000 for the frail group. Conclusion : The overall prognosis of frail older patients who underwent intubation and artificial ventilation was poor. When providing intensive care to such patients, it is important to carefully consider their suitability for the treatment

Novel Respiratory Impedance-Based Phenotypes Reflect Different Pathophysiologies in Chronic Obstructive Pulmonary Disease Patients.

Purpose: The forced oscillation technique (FOT) is a non-invasive method to measure respiratory impedance, the respiratory resistance (Rrs) and reactance (Xrs). The disease probability measure (DPM) is a useful computed tomography (CT) imaging variable for the assessment of gas trapping and emphysema in patients with chronic obstructive pulmonary disease (COPD) using pairs of inspiratory and expiratory CT images. We aimed to develop FOT-based phenotypes and determine whether the phenotypes and their imaging characteristics could facilitate the understanding of COPD pathophysiology.Patients and methods: FOT and spirometry were examined in 164 COPD patients and 22 non-COPD smokers. COPD patients were divided into four FOT-based phenotypes (NL, normal group; RD, resistance-dominant group; XD, reactance-dominant group; and MIX, mixed group) based on the 3rd quartile values of R5 (Rrs at 5Hz) and X5 (Xrs at 5Hz) in the non-COPD group. The emphysematous lesions and the airway lesions were quantitatively assessed in CT images by low attenuation volume and the square root of the wall area of a hypothetical airway with an internal perimeter of 10 mm (√Aaw at Pi10), respectively. DPM imaging analysis was also performed in 131 COPD patients. We investigated the differences in COPD parameters between the FOT-based phenotypes.Results: √Aaw at Pi10 were significantly higher in the RD, XD, and MIX groups than in the NL group. The XD group showed lower pulmonary function and higher dyspnea scores than the RD group. No significant changes in DPM values were observed between the RD and the NL groups. The gas-trapping area was significantly higher in the XD group than in the NL group. The MIX group showed the highest dyspnea score, most emphysematous lesions, and the lowest forced expiratory volume in 1 s % predicted value.Conclusion: The FOT-based phenotyping may be useful to assess pathophysiological changes of COPD with CT assessments

Factors Affecting Energy Metabolism and Prognosis in Patients with Amyotrophic Lateral Sclerosis.

Background/aims:Nutritional status is a factor affecting prognosis in patients with amyotrophic lateral sclerosis (ALS). Here, we aimed to clarify the factors associated with hypermetabolism and the prognosticators of ALS.Methods:Forty-two inpatients (22 men, 20 women) diagnosed with ALS according to the revised El-Escorial criteria were investigated. The following data were retrospectively analyzed: anthropometric measurements, blood biochemistry, disease severity, basal energy expenditure (BEE), resting energy expenditure (REE) measured by indirect calorimetry, spirometry, and bioelectrical impedance analysis. Single and multiple regression analysis was performed to examine factors affecting REE and metabolic changes (defined as the ratio of REE to fat-free mass [FFM]). The Kaplan-Meier method was used to examine factors associated with the occurrence of cumulative events (death or tracheostomy).Results:Among the 42 inpatients, REE was significantly higher than BEE, indicating hypermetabolism in ALS. Multiple regression analysis revealed that REE/FFM is strongly associated with the skeletal muscle index (-3.746 to -1.532, p < 0.0001) and percent forced vital capacity (%FVC) (-0.172 to -0.021, p = 0.013). Moreover, both the skeletal muscle index and %FVC were significant prognosticators associated with the occurrence of cumulative events.Conclusions:Energy metabolism was elevated in ALS, and respiratory status and muscle mass were associated with the hypermetabolism and poor prognosis. Adequate nutritional support may improve outcomes in ALS by preventing deterioration of respiratory status and reduction in muscle mass

Prediction of radiation pneumonitis using dose-volume histogram parameters with high attenuation in two types of cancer: A retrospective study.

The constraint values of dose-volume histogram (DVH) parameters for radiation pneumonitis (RP) prediction have not been uniform in previous studies. We compared the differences between conventional DVH parameters and DVH parameters with high attenuation volume (HAV) in CT imaging in both esophageal cancer and lung cancer patients to determine the most suitable DVH parameters in predicting RP onset. Seventy-seven and 72 patients who underwent radiation therapy for lung cancer and esophageal cancer, respectively, were retrospectively assessed. RP was valued according to the Common Terminology Criteria for Adverse Events. We quantified HAV with quantitative computed tomography analysis. We compared conventional DVH parameters and DVH parameters with HAV in both groups of patients. Then, the thresholds of DVH parameters that predicted symptomatic RP and the differences in threshold of DVH parameters between lung cancer and esophageal cancer patient groups were compared. The predictive performance of DVH parameters for symptomatic RP was compared using the area under the receiver operating characteristic curve. Mean lung dose, HAV30% (the proportion of the lung with HAV receiving ≥30 Gy), and HAV20% were the top three parameters in lung cancer, while HAV10%, HAV5%, and V10 (the percentage of lung volume receiving 10 Gy or more) were the top three in esophageal cancer. By comparing the differences in the threshold for parameters predicting RP between the two cancers, we saw that HAV30% retained the same value in both cancers. DVH parameters with HAV showed narrow differences in the threshold between the two cancer patient groups compared to conventional DVH parameters. DVH parameters with HAV may have higher commonality than conventional DVH parameters in both patient groups tested

マンセイ ケイカ ノ ハイ センイショウ ニ カンスル ケンキュウ

京都大学0048新制・課程博士博士(医学)甲第9856号医博第2538号新制||医||813(附属図書館)UT51-2003-C624京都大学大学院医学研究科内科系専攻(主査)教授 和田 洋巳, 教授 真鍋 俊明, 教授 三嶋 理晃学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Radiological Approach to Asthma and COPD-The Role of Computed Tomography

Asthma and chronic obstructive pulmonary disease (COPD) are among the most prevalent lung diseases. In both asthma and COPD, airway inflammation leads to airway remodeling. Parenchyma of the lung is also influenced by disease conditions. Airway wall thickening/lumen narrowing and parenchymal destruction occur in COPD. In asthma, airway remodeling contributes to the lung parenchyma. Computed tomography (CT) has been widely used as an imaging tool for lung diseases. With the technical advancement of CT, together with the development of analysis software, it is now possible to analyze the lung parenchymal change and airway remodeling quantitatively using CT. This article reviews the role of CT in assessing the lung structure and functions of patients with asthma and COPD

Development of analysis program for idiopathic pulmonary fibrosis

科学研究費補助金研究成果報告書研究種目: 基盤研究(C)研究期間: 2009～2011課題番号: 21590988研究代表者: 中野 恭幸（滋賀医科大学・医学部・講師）研究分担者: 長尾 大志（滋賀医科大学・医学部・助教