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Hemoglobins of the Lucina pectinata/bacteria symbiosis. II. An electron paramagnetic resonance and optical spectral study of the ferric proteins 总被引:1,自引:0,他引:1
D W Kraus J B Wittenberg J F Lu J Peisach 《The Journal of biological chemistry》1990,265(27):16054-16059
We report an optical and EPR spectral study of three hemoglobins, Hb I, II, and III, from the gill of the clam Lucina pectinata. Hemoglobin I reacts much more avidly with hydrogen sulfide than do Hbs II and III. The proximal ligand to the heme iron of each hemoglobin is histidyl imidazole. The acid/alkaline transition of ferric Hb I occurs with pK 9.6; those of ferric Hbs II and III with pK 6.6 and 5.9, respectively. At their acid limits each ferric hemoglobin exists as aquoferric hemoglobin. Broadening of the g = 6 resonance suggests that the bound water enjoys great positional freedom. Ferric Hb I, at the alkaline limit (pH 11), exists as ferric hemoglobin hydroxide. Ferric Hbs II and III, at their alkaline limit (pH 7.5), each exist as equal mixtures of two species. The low spin species with optical maxima near 541 and 576 nm and g values of 2.61, 2.20, and 1.82, are identified as ferric hemoglobin hydroxide. The high spin species, with optical maxima near 486 and 603 nm and g values of 6.71, 5.87, and 5.06, resemble Dicrocoelium hemoglobin and hemoglobin MSaskatoon. Here we show that Hbs II and III resemble hemoglobin MSaskatoon in which a distal tyrosinate oxygen ligated to the ferric heme iron at alkaline pH is displaced by water at acid pH. The H2S product of ferric Hb I is identified as ferric hemoglobin sulfide. 相似文献
105.
K Ikeda C Lu E C Weir M Mangin A E Broadus 《The Journal of biological chemistry》1990,265(10):5398-5402
106.
Li Minghang Tian Xiaocui An Ruidi Yang Mei Zhang Qian Xiang Fei Liu Hailin Wang Yuchun Xu Lu Dong Zhi 《Neurochemical research》2018,43(8):1703-1703
Neurochemical Research - The original version of this article unfortunately contained a mistake. The affiliation of the author Lu Xu has been submitted and published incorrectly and has been... 相似文献
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108.
Shang-Yi Lin Po-Liang Lu Kun-Bow Tsai Chun-Yu Lin Wei-Ru Lin Tun-Chieh Chen Ya-Ting Chang Chung-Hao Huang Chi-Yu Chen Chung-Chih Lai Yen-Hsu Chen 《Mycopathologia》2012,174(5-6):499-504
Mucormycosis is an invasive fungal infection associated with a high mortality rate, especially in immunocompromised hosts. Mucormycosis rarely occurs in cirrhotic patients. Here, we report a case of mucormycosis with underlying liver cirrhosis and diabetes mellitus. The patient suffered from maxillary sinusitis and osteomyelitis, and the infection was successfully treated with antifungal agents, surgical debridement, and hyperbaric oxygen therapy. The antifungal treatments used were liposomal amphotericin B, itraconazole, and posaconazole. Although our patient had liver cirrhosis (Child-Pugh classification B), no hepatic decompensation was developed during the treatment course of posaconazole. This is the first report of the safe and effective use of posaconazole for the treatment of mucormycosis in a cirrhotic patient. 相似文献
109.
Multimeric BLM is dissociated upon ATP hydrolysis and functions as monomers in resolving DNA structures 总被引:1,自引:0,他引:1
Ya-Nan Xu Nicolas Bazeille Xiu-Yan Ding Xi-Ming Lu Peng-Ye Wang Elisabeth Bugnard Virginie Grondin Shuo-Xing Dou Xu Guang Xi 《Nucleic acids research》2012,40(19):9802-9814
Bloom (BLM) syndrome is an autosomal recessive disorder characterized by an increased risk for many types of cancers. Previous studies have shown that BLM protein forms a hexameric ring structure, but its oligomeric form in DNA unwinding is still not well clarified. In this work, we have used dynamic light scattering and various stopped-flow assays to study the active form and kinetic mechanism of BLM in DNA unwinding. It was found that BLM multimers were dissociated upon ATP hydrolysis. Steady-state and single-turnover kinetic studies revealed that BLM helicase always unwound duplex DNA in the monomeric form under conditions of varying enzyme and ATP concentrations as well as 3′-ssDNA tail lengths, with no sign of oligomerization being discerned. Measurements of ATPase activity further indicated that BLM helicase might still function as monomers in resolving highly structured DNAs such as Holliday junctions and D-loops. These results shed new light on the underlying mechanism of BLM-mediated DNA unwinding and on the molecular and functional basis for the phenotype of heterozygous carriers of BLM syndrome. 相似文献
110.
Apolygus lucorum (Meyer-Dür) (Heteroptera: Miridae) is a significant insect pest of cotton, Chinese dates, grapes and many other crops in
China, and its populations typically increase after heavy rains. However, the intrinsic mechanism of the rainfall-dependent
outbreak is not yet fully understood. In our study, the effect of different relative humidity (RH), 40, 50, 60, 70, and 80%
RH, on population growth of A. lucorum was evaluated in the laboratory. High humidity (e.g. 70 and 80% RH) was observed to significantly increase egg and nymph
survival, prolong adult life longevity, and improve female fecundity. However, low humidity (e.g. 40 and 50% RH) led to unfavorable
effects on survival and fecundity. As a result, the intrinsic capacity for increase (r
m), net production (R
o), and the finite rate of increase (λ) of A. lucorum population greatly increased with increasing relative humidity. Additionally, the relationships between r
m and R
o and relative humidity were good fits to the logistic models y = 36.82/(1 + Exp(10.76 − 0.19x)) (p < 0.001) and y = 0.10/(1 + Exp(9.26 − 0.19x)) (p = 0.003), respectively. This study provides insight into the phenology of A. lucorum, and may contribute to modeling of its population dynamics. 相似文献