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HE Xiaolin LIU Xinqi ZENG Zonghao LI Hongmin WANG Miao ZHANG Ying WANG Dacheng 《中国科学C辑(英文版)》2000,43(1):39-46
BmK M4 is a neutral neurotoxin in the BmK toxin series.It is medially toxic and belongs to group III α-toxins.The purified sample was crystallized in rhombic space group P61.Using an X-ray diffraction technique,the crystal structure of BmK M4 was revealed by molecular replacement at 0.20 nm resolution.The model was refined.The final crystallographic R factor was 0.142 and the free R factor was 0.173.The root mean square deviation is 0.001 5 nm for the bond length and 1.753°for the bond angles.64 water molecules were added to the asymmetric unit.The refined structure showed an unusual non-prolyl cis peptide bond at residue 10.The structure was compared with group II α-toxin BmK M8 (an acidic,weak toxin).The potential structural implications of the cis peptide bond were discussed. 相似文献
3.
The selenium-containing phycocyanin from the selenium-rich algae (Spirulina platensis) has been crystallized in two crystal forms by the hanging-drop vapor diffusion techniques. A chromatographic procedure of gel filtration and anion exchange was used for purification. Form I crystal with space group P21 and cell parameters a =108.0 ?, b= 117.0 ?, c = 184.0?, β= 90.2° and 12(αβ) units in the asymmetric unit was obtained by using (NH4)2SO4 as precipitant. These crystals diffract up to 2.8 ?. Form II crystal obtained by using PEG4000 as precipitant belongs to space group P63 with unit cell constants a = 155.0 ?, c = 40.3 ?, γ =120.0° and one(αβ) unit in the asymmetric unit. The crystals diffract beyond 2.9 ?. The possible stacking forms of phycocyanin molecules in the first crystal form were discussed. 相似文献
4.
The model conjugates phycocyanin-allophycocyanin (C-PC-APC) and phycoerythrocyanin-phycocyanin-allophycocyanin (PEC-C-PC-APC)
were synthesized by using a heterobifunctional coupling reagent N-succinimidyl-3-(2-pyridyldithio)propionate. The rod-core
complex (αβ)6
PCLRC
27(αβ)3
APCLC
8.9 and phycobilisomes were separated from Anabaena variabilis. Energy transfer features for the conjugates and the complexes
were compared. The absorption and fluorescence emission spectra indicated that the linker-peptides mediate interaction of
phycobiliproteins and prompt energy transfer. The energy transfer in the conjugates was detected by fluorescence emission
spectra and confirmed by the addition of dithiothreitol. The conjugates may be used as models for studying the energy transfer
mechanism in phycobilisomes.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
5.
Phenyllactic acid (PLA) is a novel antimicrobial compound derived from phenylalanine (Phe). Lactobacillus sp. SK007, having high PLA-producing ability, was isolated from Chinese traditional pickles. When 6.1 mM phenylpyruvic acid
(PPA) was used to replace Phe as substrate at the same concentration, PLA production increased 14-fold and the fermentation
time decreased from 72 h to 24 h with growing cells. With resting cells, however, 6.8 mM PLA could be obtained as optimal
yield using the following conditions: 12 mM PPA, 55 mM glucose, pH 7.5, 35°C and 4 h. 相似文献
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腹腔注射链脲佐霉素(65mg/kg)诱发Wistar大鼠糖尿病。糖尿病发病4周后,向饲料中加尼群地平(30mg·kg-1·d-1)。结果表明,糖尿病4周时大鼠心室舒张功能首先受损,8周后心室舒张和收缩功能均明显受累。尼群地平处理对糖尿病大鼠的心肌收缩性有一定的改善作用。提示尼群地平对大鼠糖尿病性心肌病有一定有益作用。 相似文献
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Gen-Hong Wang Chun Liu Qing-You Xia Xing-Fu Zha Jie Chen Liang Jiang 《Insect Science》2008,15(3):201-208