Structure and Function of the Xenobiotic Substrate-Binding Site and Location of a Potential Non-Substrate-Binding Site in a Class π GlutathioneS-Transferase†,‡

Biochemistry ◽  
1997 ◽  
Vol 36 (32) ◽  
pp. 9690-9702 ◽  
Author(s):  
Xinhua Ji ◽  
Maria Tordova ◽  
Rosemary O'Donnell ◽  
James F. Parsons ◽  
Janet B. Hayden ◽  
...  
Keyword(s):  
Binding Site ◽  
Substrate Binding ◽  
Structure And Function ◽  
Substrate Binding Site ◽  
And Function

Structure and Function of Residue 104 and Water Molecules in the Xenobiotic Substrate-Binding Site in Human GlutathioneS-Transferase P1-1†,‡

Biochemistry ◽  
1999 ◽  
Vol 38 (32) ◽  
pp. 10231-10238 ◽  
Author(s):  
Xinhua Ji ◽  
Jaroslaw Blaszczyk ◽  
Bing Xiao ◽  
Rosemary O'Donnell ◽  
Xun Hu ◽  
...  
Keyword(s):  
Binding Site ◽  
Substrate Binding ◽  
Structure And Function ◽  
Water Molecules ◽  
Substrate Binding Site ◽  
And Function

scholarly journals Mechanism of Tissue Factor Activation on HL-60 Cells

Blood ◽  
1997 ◽  
Vol 89 (9) ◽  
pp. 3270-3276 ◽  
Author(s):  
Ronald R. Bach ◽  
Charles F. Moldow
Keyword(s):  
Binding Site ◽  
Tissue Factor ◽  
Quaternary Structure ◽  
Factor Viia ◽  
Calcium Ionophore ◽  
Structure And Function ◽  
Cross Linking ◽  
Substrate Binding Site ◽  
Pseudosubstrate Inhibitors ◽  
And Function

AbstractTissue factor (TF ) procoagulant activity (PCA) on the surface of intact HL-60 cells is encrypted. This latent TF PCA was activated by exposing the cells to ionomycin, a calcium ionophore. Within seconds an increase in TF PCA of greater than 100-fold was observed. The ionomycin effect was blocked by pretreating the cells with calmidazolium, a calmodulin inhibitor. Changes in TF structure and function, coincident with the ionophore-induced increase in TF PCA, were identified. TF-factor VIIa complexes formed on both untreated and ionophore-treated cells, but pseudosubstrate inhibitors only bound to TF-factor VIIa on the ionophore-treated cells. TF PCA was inhibited by reacting cells with sulfosuccinimidyl-6-(biotinamido)hexanoate, and the rate of this reaction increased twofold after cells were exposed to ionomycin. When proteins on the surface of untreated cells, expressing minimal TF PCA, were cross-linked with 3-3′-dithiobis(sulfosuccinimidylpropionate), cross-linked TF dimers were produced. TF cross-linking was prevented by first treating the cells with ionomycin. These results suggest a mechanism for the ionomycin-induced increase in TF PCA. TF activation appears to be a calmodulin-dependent process, which exposes an essential macromolecular substrate binding site on TF, possibly as the result of a change in TF quaternary structure.

Comprehensive in silico Study of GLUT10: Prediction of Possible Substrate Binding Sites and Interacting Molecules

2020 ◽  
Vol 21 (2) ◽  
pp. 117-130 ◽  
Author(s):  
Mohammad J. Hosen ◽  
Mahmudul Hasan ◽  
Sourav Chakraborty ◽  
Ruhshan A. Abir ◽  
Abdullah Zubaer ◽  
...  
Keyword(s):  
Virtual Screening ◽  
Binding Site ◽  
Glucose Transporter ◽  
Substrate Binding ◽  
Mutation Screening ◽  
Homology Model ◽  
Connective Tissue Disorder ◽  
Crystallographic Structure ◽  
Substrate Binding Site

Objectives: The Arterial Tortuosity Syndrome (ATS) is an autosomal recessive connective tissue disorder, mainly characterized by tortuosity and stenosis of the arteries with a propensity towards aneurysm formation and dissection. It is caused by mutations in the SLC2A10 gene that encodes the facilitative glucose transporter GLUT10. The molecules transported by and interacting with GLUT10 have still not been unambiguously identified. Hence, the study attempts to identify both the substrate binding site of GLUT10 and the molecules interacting with this site. Methods: As High-resolution X-ray crystallographic structure of GLUT10 was not available, 3D homology model of GLUT10 in open conformation was constructed. Further, molecular docking and bioinformatics investigation were employed. Results and Discussion: Blind docking of nine reported potential in vitro substrates with this 3D homology model revealed that substrate binding site is possibly made with PRO531, GLU507, GLU437, TRP432, ALA506, LEU519, LEU505, LEU433, GLN525, GLN510, LYS372, LYS373, SER520, SER124, SER533, SER504, SER436 amino acid residues. Virtual screening of all metabolites from the Human Serum Metabolome Database and muscle metabolites from Human Metabolite Database (HMDB) against the GLUT10 revealed possible substrates and interacting molecules for GLUT10, which were found to be involved directly or partially in ATS progression or different arterial disorders. Reported mutation screening revealed that a highly emergent point mutation (c. 1309G>A, p. Glu437Lys) is located in the predicted substrate binding site region. Conclusion: Virtual screening expands the possibility to explore more compounds that can interact with GLUT10 and may aid in understanding the mechanisms leading to ATS.

Chitosanase from Streptomyces sp. strain N174: a comparative review of its structure and function

1997 ◽  
Vol 75 (6) ◽  
pp. 687-696 ◽  
Author(s):  
Tamo Fukamizo ◽  
Ryszard Brzezinski
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Substrate Binding ◽  
Structure And Function ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Streptomyces Sp ◽  
Binding Cleft ◽  
And Function

Novel information on the structure and function of chitosanase, which hydrolyzes the beta -1,4-glycosidic linkage of chitosan, has accumulated in recent years. The cloning of the chitosanase gene from Streptomyces sp. strain N174 and the establishment of an efficient expression system using Streptomyces lividans TK24 have contributed to these advances. Amino acid sequence comparisons of the chitosanases that have been sequenced to date revealed a significant homology in the N-terminal module. From energy minimization based on the X-ray crystal structure of Streptomyces sp. strain N174 chitosanase, the substrate binding cleft of this enzyme was estimated to be composed of six monosaccharide binding subsites. The hydrolytic reaction takes place at the center of the binding cleft with an inverting mechanism. Site-directed mutagenesis of the carboxylic amino acid residues that are conserved revealed that Glu-22 and Asp-40 are the catalytic residues. The tryptophan residues in the chitosanase do not participate directly in the substrate binding but stabilize the protein structure by interacting with hydrophobic and carboxylic side chains of the other amino acid residues. Structural and functional similarities were found between chitosanase, barley chitinase, bacteriophage T4 lysozyme, and goose egg white lysozyme, even though these proteins share no sequence similarities. This information can be helpful for the design of new chitinolytic enzymes that can be applied to carbohydrate engineering, biological control of phytopathogens, and other fields including chitinous polysaccharide degradation. Key words: chitosanase, amino acid sequence, overexpression system, reaction mechanism, site-directed mutagenesis.

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