crystal form of the seven crystal systems

... attack on the anomeric carbon of fructose. The leaving group is carboxylate of Asp54. Dimerization The asymmetric units of the crystals of both the apo and complexed form of the enzyme consist of dimers with ... maps. The crystal structure of the complex of b-fructofura- nosidase with fructose was solved by molecular replacement using the crystal structure of the native enzyme as the search model. The ... blades in the axis area are of polar character. The water channel in the apo form of the enzyme runs along the axis of the b-propeller through the whole domain and is only blocked by Cys236 in the...

Ngày tải lên: 06/03/2014, 00:21

Ngày tải lên: 23/03/2014, 15:21

... counted the interactions, we excluded all residues involved in the binding of the metal cofactor. ApeSODs in different forms were superimposed with the least square fit of Ca atoms of the residues ... ligand, NE2 of His31, bound to the metal, in the company of a water oxygen, from the apical positions. The manga- nese was only 0.06 A ˚ out of the equatorial plane (Table 3). The angles around the metal ... additional water oxy- gen, which, together with the OD2 of Asp165, the NE2 of His79 and the NE2 of His169, formed an equatorial plane (Fig. 3B). The metal ion and the addi- tional water oxygen were...

Ngày tải lên: 14/02/2014, 22:20

... regulatory mechanism of Thr and the struc- tural features responsible for the high thermostability of TtAKb. Results and Discussion Model quality The crystal structure of the Thr-bound form of TtAKb (TtAKb-Thr) ... good quality, with 95.4% of the res- idues in the most favored regions and 4.6% in allowed regions of the Ramachandran plot. The crystal structure of the Thr-free form of TtAKb (TtAKb-free) was ... binding shifts the equilibrium to dimer formation. In the absence of Thr, an outward shift of b-strands near the Thr-binding site (site 1) and a concomitant loss of the electron density of the loop...

Ngày tải lên: 18/02/2014, 08:20

... Ser214–Gly219 (the entrance frame), Lys224– Tyr228 (the back of the pocket) and the disulfide bridge Cys191–Cys220 (the front of the pocket) (Fig. 4A). The backbones of these segments form a deep ... below). The southern boundary of the active site cleft of DESC1 is formed by the 145 autolysis loop. The backbone of this loop differs mark- edly from the other serine proteinases, making the act- ive ... reveals that the most similar regions of these proteinases medi- ate interaction of the two b-barrels, formation of the catalytic machinery and structures required for binding of the main chain of the...

Ngày tải lên: 19/02/2014, 00:20

... active site formation. Sections (6 A ˚ thick) of the protein surface that illustrate the shape and size of the active site. The sphere represents the zinc ion. (A) The main body of the active ... acetate which is the product of a deacetylation reaction. (c) The protein forms stable homohexamers both in the crystal form and in solution. Thus, the functional state of the enzyme is probably the hexamer. ... determines the shape of the active site entry. (e) The structure of the active site is essentially identical with the active sites of the MshB and LpxC proteins. The conservation of catalytically important...

Ngày tải lên: 19/02/2014, 00:20

... the Cys73–Cys73 disulfide bond [23]. The substitution of these hydrogen bond forming residues in hTRXL-N may account for the formation of a monomer, instead of a dimer in the case of TRX. Furthermore, ... dissimilar crystal forms and dissimilar intermolecular contacts near the active site in the crystal, the conformation of the active site (-Cys-Gly-Pro- Cys-) of the hTRXL-N determined in the present ... little direct effect on the activity of the enzyme. The function of this unique C-terminal domain remains unknown. Overall structure Crystals of the catalytic domain of hTRXL (hTRXL-N) were obtained...

Ngày tải lên: 08/03/2014, 22:20

... part, and (b) the variability of the angle of approach of the inhibitor relative to the catalytic cleft of the enzyme. The latter factor may reflect not so much the geometry of the catalytic site ... PW), despite the lack of overall sequence similarity. The role of the proline residue appears to be to maintain the specific shape of the loop. The aromatic residue, on the other hand, interacts with the ... [20,21]. The other segment of the guanidinium group of R91 forms a pair of hydrogen bonds with the oxygen atom of the side-chain amide group of N18e. It is interesting to note that the equivalent...

Ngày tải lên: 16/03/2014, 04:20

... subunits of both crystal forms (diagonal terms). Please note the symmetry of crystal form 1 and asymmetry of crystal form 2 represented by low and high values of the rmsd, respectively. Subunit a Crystal ... In the center there is a schematic of the mutual relationship of the monomers, in selected members of the family, as indi- cated by the twist angle of the dimer. TM1415 constitutes one of the ... 1. Schematic of the transformation of TM1415 into the eukaryotic FBPase. The transformation requires  25° rotation of the dimers around the tetramer axis and  30° rotation of the monomers in...

Ngày tải lên: 16/03/2014, 11:20

... but, like the d and d¢ subunits of the clamp-loader, neither v nor w contain any of the functional elements required for nucleotide binding. The topology of the w subunit resembles that of the bacterial ... of w,fromthelistofsequencesgivenin Table 3, is shown. The alignment is colored according to the degree of sequence conservation. These 26 residues are disordered in the crystal structure of the ... protein via the distal surface of v. The base of the clamp-loader complex has an open C-shaped structure, and the shape of the v:w com- plex is suggestive of a loose docking within the crevice formed by...

Ngày tải lên: 16/03/2014, 16:20

... molecule to form an isopeptide bond with the Gly93 of another. The crystal structures of diubiquitin and tetraubiquitin showed some alternatives of the quaternary c onformations of ubiquitin ... chains, their conformations were adjusted with reference t o the NMR structure of SUMO-1 and the crystal structure of yeast A CD B Fig. 2. Photographs and electron density maps of the SUMO-2 crystals. ... residues 45–58 in the former model and 40 , 49 and 55–58 in the latter model of SUMO-2 and the equivalents of ubiquitin. Although the sequences have only 18% identity, the protein folds of SUMO-2 and...

Ngày tải lên: 16/03/2014, 18:20

Ngày tải lên: 22/03/2014, 21:20

Ngày tải lên: 23/03/2014, 09:21

Ngày tải lên: 29/03/2014, 21:20

Ngày tải lên: 30/03/2014, 10:20

Ngày tải lên: 30/03/2014, 14:20

Ngày tải lên: 26/12/2013, 01:18

Ngày tải lên: 03/01/2014, 19:39

... live in a snake. 14. My brother managed to kill the snake just at the time when I were almost exhausted. Supply the correct form of the verbs 1. Cats could fly if they (have) wings. 2. If Peter ... (not,want) to live in a snake. 14. My brother managed to kill the snake just at the time when I (be) almost exhausted. If he (be) a little late, I (kill) by the snake. 15. Had I know you were ill, ... snake. 14. My brother managed to kill the snake just at the time when I (be) had been almost exhausted. If he (be) had been a little late, I (kill) would have been killed by the snake. 15. Had...

Ngày tải lên: 23/01/2014, 07:20