Protein crystal growth is quite important for the determination of protein structureswhich are essential to the understanding of life at molecular level as well as to the development of molecu-lar biotechnology.The mi...Protein crystal growth is quite important for the determination of protein structureswhich are essential to the understanding of life at molecular level as well as to the development of molecu-lar biotechnology.The microgravity environment of space is an ideal place to study the complicated pro-tein crystallization and to grow good-quality protein crystals.A number of crystal-growth experiments of10 different proteins were carried out in August,1992 on the Chinese re-entry satellite FSW-2 in spaceusing a tube crystallization equipment made in China.A total of 25 samples from 6 proteins producedcrystals,and the effects of microgravity on protein crystal growth were observed,especially for an acidicphospholipase A2 and henegg-white lysozyme which gave better crystals in space than earth-grown crys-tals in ground control experiments.The results have shown that the microgravity in space favors the im-provement of the size,perfection,morphology and internal order of the grown protein crytals.展开更多
Trichosanthin is an efficacious Chinese medicine for terminating pregnancy and inhibiting trophoblastic tumours. It is extracted from the root tuber of trichosanthes kirilowii, cucurbitaceae. Sequence homology studies...Trichosanthin is an efficacious Chinese medicine for terminating pregnancy and inhibiting trophoblastic tumours. It is extracted from the root tuber of trichosanthes kirilowii, cucurbitaceae. Sequence homology studies and rabbit retiulocyte cell-free system experiments have shown that trichosanthin belongs to type Ⅰ ribosome-inactivating protein (RIP). Its crystal structure at atomic resolution has been reported in the previous paper. Here we report our preliminary crystal-展开更多
An X-ray reflection data set of the orthorhombic crystal of Trichosanthin(TCS) at 1. 73 A resolution had been collected using the area detector. We determined TCS crystal structure by the molecular replacement method ...An X-ray reflection data set of the orthorhombic crystal of Trichosanthin(TCS) at 1. 73 A resolution had been collected using the area detector. We determined TCS crystal structure by the molecular replacement method using the data of the known α-momorcharin model and TCS intensities , and then TGS structure refinement at 1. 73 A resolution was performed with the restrained least-squares refinement. A final R-factor of 0.186 was obtained with a model obeying standard geometry within 0. 013A in bond lengths and 2. 48° in bond angles. The final model contains 133 solvent molecules in the asymmetric unit. This paper gives a detailed description of TCS molecular structure, temperature factors, hydrogen bonds, bound water, the distribution of conserved residues and the interactions between the TCS molecules. The hydrogen bond between the hydroxyl group of conserved residue 14Tyr and O157 plays an important role in maintaining the active site conformation. Conserved residue 160Glu and its conformation at展开更多
The water-structure model in Trichosanthin crystal is presented,and 133 water moleculesare included and 118 water molecules are hydrogen-bonded to protein.In the interior of Trichosanthin,thereare four discrete intern...The water-structure model in Trichosanthin crystal is presented,and 133 water moleculesare included and 118 water molecules are hydrogen-bonded to protein.In the interior of Trichosanthin,thereare four discrete internal water molecules,among which two water molecules W251 and W252 are separated-ly hydrogen-bonded to the side-chain groupsof 156Gln and 157Ser in the distorted segment of A5 helix andplay a role in maintaining the conformation of the active site.The comparative result of water structures incrystals indicates that when approaching the protein,the ribosome induces a conformational change in theresidues of the active site,which leads to an appropriate alignment of catalytic groups as well as the optimalconformation for the catalysis,and activates a water molecule (W257) to participate in the ribosome inactiva-tion.展开更多
文摘Protein crystal growth is quite important for the determination of protein structureswhich are essential to the understanding of life at molecular level as well as to the development of molecu-lar biotechnology.The microgravity environment of space is an ideal place to study the complicated pro-tein crystallization and to grow good-quality protein crystals.A number of crystal-growth experiments of10 different proteins were carried out in August,1992 on the Chinese re-entry satellite FSW-2 in spaceusing a tube crystallization equipment made in China.A total of 25 samples from 6 proteins producedcrystals,and the effects of microgravity on protein crystal growth were observed,especially for an acidicphospholipase A2 and henegg-white lysozyme which gave better crystals in space than earth-grown crys-tals in ground control experiments.The results have shown that the microgravity in space favors the im-provement of the size,perfection,morphology and internal order of the grown protein crytals.
文摘Trichosanthin is an efficacious Chinese medicine for terminating pregnancy and inhibiting trophoblastic tumours. It is extracted from the root tuber of trichosanthes kirilowii, cucurbitaceae. Sequence homology studies and rabbit retiulocyte cell-free system experiments have shown that trichosanthin belongs to type Ⅰ ribosome-inactivating protein (RIP). Its crystal structure at atomic resolution has been reported in the previous paper. Here we report our preliminary crystal-
文摘An X-ray reflection data set of the orthorhombic crystal of Trichosanthin(TCS) at 1. 73 A resolution had been collected using the area detector. We determined TCS crystal structure by the molecular replacement method using the data of the known α-momorcharin model and TCS intensities , and then TGS structure refinement at 1. 73 A resolution was performed with the restrained least-squares refinement. A final R-factor of 0.186 was obtained with a model obeying standard geometry within 0. 013A in bond lengths and 2. 48° in bond angles. The final model contains 133 solvent molecules in the asymmetric unit. This paper gives a detailed description of TCS molecular structure, temperature factors, hydrogen bonds, bound water, the distribution of conserved residues and the interactions between the TCS molecules. The hydrogen bond between the hydroxyl group of conserved residue 14Tyr and O157 plays an important role in maintaining the active site conformation. Conserved residue 160Glu and its conformation at
基金the National"863"High Techonolgy Foundation of China
文摘The water-structure model in Trichosanthin crystal is presented,and 133 water moleculesare included and 118 water molecules are hydrogen-bonded to protein.In the interior of Trichosanthin,thereare four discrete internal water molecules,among which two water molecules W251 and W252 are separated-ly hydrogen-bonded to the side-chain groupsof 156Gln and 157Ser in the distorted segment of A5 helix andplay a role in maintaining the conformation of the active site.The comparative result of water structures incrystals indicates that when approaching the protein,the ribosome induces a conformational change in theresidues of the active site,which leads to an appropriate alignment of catalytic groups as well as the optimalconformation for the catalysis,and activates a water molecule (W257) to participate in the ribosome inactiva-tion.
