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21.
The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSII),mainly the effect of PG on conformation and microenvironment of tyrosine residues of PSII proteins were studied by Fourier transform infrared (FTIR) spectroscopy.It was found that the binding of PG to PSII particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues.In other words,the PG effect on the PSII results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm-1 with the enhancement of the absorbance intensity.Additionally,a new spectrum of hydrogen bond was also observed.The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSII proteins. 相似文献
22.
Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent
years. In this work, we reported the first use of THz-TDS to examine the denaturation of two photosynthesis membrane proteins:
CP43 and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with
similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl),
a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.
Supported by the National Natural Science Foundation of China (Grant No. 39890390) 相似文献
23.
Shuqin Li Guiying Chen Guangye Han Lin Ling Deguang Huang A. A. Khorobrykh S. K. Zharmukhamedov Qiutian Liu V. V. Klimov Tingyun Kuang 《Journal of biological inorganic chemistry》2006,11(6):783-790
The water-oxidizing complex (WOC) within photosystem II (PSII) can be reconstituted with synthetic manganese complexes by a process called photoactivation; however, the key factors affecting the efficiency of synthetic manganese complexes in reconstitution of electron transport and oxygen evolution activity in manganese-depleted PSII remain unclear. In the present study, four complexes with different manganese coordination environments were used to reconstitute the WOC, and an interesting relationship was found between the coordination environment of the manganese atom in the complexes and their efficiency in restoring electron transport and oxygen evolution. If Mn(II) is coordinated to nitrogen atoms within the ligand, it can restore significant rates of electron transport and oxygen evolution; however, if the manganese atom is coordinated only to oxygen atoms instead of nitrogen atoms, it has no capability to restore electron transport and oxygen evolution. So, our results demonstrate that the capability of manganese complexes to reconstitute the WOC is mainly determined by the coordination between nitrogen atoms from ligands and the manganese atom. It is suggested from our results that the ligation between the nitrogen atom and the manganese atom within the manganese complex facilitates the photoligation of the manganese atom to histidyl residues on the apo-protein in manganese-depleted PSII during photoactivation. 相似文献
24.
Xiaoqin Wang Pingfang Yang Xiaofeng Zhang Yinong Xu Tingyun Kuang Shihua Shen Yikun He 《Proteomics》2009,9(19):4529-4538
Cold stress has adverse effects on plant growth and development. Plants respond and acclimate to cold stress through various biochemical and physiological processes, thereby acquiring stress tolerance. To better understand the basis for tolerance, we carried out a proteomic study in the model moss, Physcomitrella patens, characterizing gametophore proteins with 2‐DE and mass spectroscopy. Following exposure to 0°C for up to 3 days, out of the more than 1000 protein spots reproducibly resolved, only 45 changed in abundance by at least 1.5‐fold. Of these, 35 were identified by tryptic digestion and mass spectroscopy. Photosynthetic proteins decreased, whereas many catabolic proteins increased. In addition, cold stress up‐regulated a variety of signaling, cytoskeleton, and defense proteins and few proteins in these classes were down‐regulated. Up‐regulated proteins include the 14‐3‐3‐like protein, actin, HSP70s, lipoxygenases, and cytochrome P450 proteins. These results point to pathways that are important for the mechanism of cold stress response in P. patens and by extension to the entire plant kingdom. 相似文献
25.
Thelightharvestingchlorophylla/bproteincomplex(LHCII)associatedwithphotosystemIIisthemostabundantpigmentproteincomplexinchloroplastthylakoidofallgreenplants.Itcontainsabout50%ofthetotalamountofpigmentsinvolvedinplantphotosynthesis.LHCIIperformsimportantf… 相似文献
26.
Congming Lu Nianwei Qiu Qingtao Lu Baoshan Wang Tingyun Kuang 《Physiologia plantarum》2003,118(2):173-182
Kalanchoë daigremontiana, a CAM plant grown in a greenhouse, was subjected to severe water stress. The changes in photosystem II (PSII) photochemistry were investigated in water‐stressed leaves. To separate water stress effects from photoinhibition, water stress was imposed at low irradiance (daily peak PFD 150 μmol m?2 s?1). There were no significant changes in the maximal efficiency of PSII photochemistry (Fv/Fm), the traditional fluorescence induction kinetics (OIP) and the polyphasic fluorescence induction kinetics (OJIP), suggesting that water stress had no direct effects on the primary PSII photochemistry in dark‐adapted leaves. However, PSII photochemistry in light‐adapted leaves was modified in water‐stressed plants. This was shown by the decrease in the actual PSII efficiency (ΦPSII), the efficiency of excitation energy capture by open PSII centres (Fv′/Fm′), and photochemical quenching (qP), as well as a significant increase in non‐photochemical quenching (NPQ) in particular at high PFDs. In addition, photoinhibition and the xanthophyll cycle were investigated in water‐stressed leaves when exposed to 50% full sunlight and full sunlight. At midday, water stress induced a substantial decrease in Fv/Fm which was reversible. Such a decrease was greater at higher irradiance. Similar results were observed in ΦPSII, qP, and Fv′/Fm′. On the other hand, water stress induced a significant increase in NPQ and the level of zeaxanthin via the de‐epoxidation of violaxanthin and their increases were greater at higher irradiance. The results suggest that water stress led to increased susceptibility to photoinhibition which was attributed to a photoprotective process but not to a photodamage process. Such a photoprotection was associated with the enhanced formation of zeaxanthin via de‐epoxidation of violaxanthin. The results also suggest that thermal dissipation of excess energy associated with the xanthophyll cycle may be an important adaptive mechanism to help protect the photosynthetic apparatus from photoinhibitory damage for CAM plants normally growing in arid and semi‐arid areas where they are subjected to a combination of water stress and high light. 相似文献
27.
Exposure of intact rice leaves to an irradiance of 1000 μmol m−2 s−1 at 6 °C for 2 h caused severe photoinhibition of Photosystem II. The rate and extent of photoinhbition were greatly exacerbated
in leaves fed with 10 mM reduced glutathione (GSH) or 10 mM cysteine. Analyses of antioxidant enzyme activities as well as
the application of protein synthesis inhibitors revealed that the increased sensitivity to photoinhibition following GSH feeding
was not related to its effect on cellular antioxidant systems. On the other hand, feeding with GSH markedly suppressed the
formation of zeaxanthin and antheraxanthin via the xanthophyll cycle and its associated nonradiative energy dissipation in
leaves chilled in high light, suggesting that the stimulating effect of exogenous GSH on photoinhibition may be attributable
to its action on the xanthophyll cycle. In vitro experiments using isolated thylakoids indicated that GSH is a weak inhibitor of violaxanthin deepoxidation. The possible
implications of these results are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
28.
A pure, active cytochrome b
6
f was isolated from the chloroplasts of the marine green alga, Bryopsis
corticulans. To investigate and characterize this cytochrome b
6
f complex, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), absorption spectra measurement and HPLC were employed. It was shown that this purified complex contained four large subunits with apparent molecular masses of 34.8, 24, 18.7 and 16.7 kD. The ratio of Cyt b
6 to Cytf was 2.01 : 1. The cytochromeb
6
f was shown to catalyze the transfer of 73 electrons from decylplastoquinol to plastocyanin–ferricyanide per Cyt f per second. α-Carotene, one kind of carotenoid that has not been found to present in cytochrome b
6
f complex, was discovered in this preparation by reversed phase HPLC. It was different from β-carotene usually found in cytochrome b
6
f complex. The configuration of the major α-carotene component was assigned to be 9-cis by resonance Raman spectroscopy. Different from the previous reports, the configuration of this α-carotene in dissociated state was determined to be all-trans. Besides this carotene, chlorophyll a was also found in this complex. It was shown that the molecular ratios of chlorophylla, cis and all-trans-α-carotene to Cyt f in this complex were 1.2, 0.7 and 0.2, respectively. 相似文献
29.
The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSII),mainly the effect of PG on conformation and microenvironment of tyrosine residues of PSII proteins were studied by Fourier transform infrared (FTIR) spectroscopy.It was found that the binding of PG to PSII particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues.In other words,the PG effect on the PSII results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm-1 with the enhancement of the absorbance intensity.Additionally,a new spectrum of hydrogen bond was also observed.The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSII proteins. 相似文献
30.
萝Mo科马利筋族植物化学成分研究进展(Ⅱ) 总被引:1,自引:0,他引:1
综述了到目前为止,从马利筋族植物中发现的黄酮、强心甙、生物碱、萜类、苯衍生物类等成分的种类及其分布,并介绍了一些化合物的药理作用以及黄酮类和C21甾体化合物 鹅绒藤属化学分类中的作用。 相似文献