Structural studies on bio-active compounds. Part 3. Re-examination of the hydrolysis of the antimalarial drug pyrimethamine and related derivatives and crystal structure of a hydrolysis product

Author(s):  
Roger J. Griffin ◽  
Carl H. Schwalbe ◽  
Malcolm F. G. Stevens ◽  
Kait P. Wong
2019 ◽  
Vol 10 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Koffi Senam Etse ◽  
Guillermo Zaragoza ◽  
Bernard Pirotte

The hydrolysis of 2-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (2) during crystallization under humidity (85 %) conditions, lead to N-(2-(N-methylsulfamoyl)phenyl)formamide as second step hydrolysis product, identified in the proposed degradation mechanism. Crystal of N-(2-(N-methylsulfamoyl)phenyl)formamide C8H10N2O3S (4), was obtained and characterized. The molecular structure determination was carried out with MoKα X-ray and data measured at 100 K. The compound 4 crystallizes in triclinic P͞1 space group with unit cell parameters a = 4.8465(4) Å, b = 8.1942(9) Å, c = 11.8686(13) Å, α = 77.080(4)°, β = 82.069(4)°, γ = 80.648(4)°, V = 450.76 (8) Å3 and Z = 2. The crystal structure is stabilized by intramolecular N-H···O and intermolecular C-H···O and N-H···O hydrogen bonds that extended as infinite 1D chain along [100]. Stabilization is also ensured by oxygen-π stacking interaction between the aromatic ring and oxygen of the sulfonamide group. The analysis of intermolecular interactions through the mapping of dnorm and shape-index revel that the most significant contributions to the Hirshfeld surface 40.6 and 33.9% are from H···H and O···H contacts, respectively.


2017 ◽  
Vol 37 (3) ◽  
Author(s):  
Lifang Sun ◽  
Pu Chen ◽  
Yintao Su ◽  
Zhixiong Cai ◽  
Lingwei Ruan ◽  
...  

A novel alkylsulfatase from bacterium Pseudomonas sp. S9 (SdsAP) was identified as a thermostable alkylsulfatases (type III), which could hydrolyze the primary alkyl sulfate such as sodium dodecyl sulfate (SDS). Thus, it has a potential application of SDS biodegradation. The crystal structure of SdsAP has been solved to a resolution of 1.76 Å and reveals that SdsAP contains the characteristic metallo-β-lactamase-like fold domain, dimerization domain, and C-terminal sterol carrier protein type 2 (SCP-2)-like fold domain. Kinetic characterization of SdsAP to SDS by isothermal titration calorimetry (ITC) and enzymatic activity assays of constructed mutants demonstrate that Y246 and G263 are important residues for its preference for the hydrolysis of ‘primary alkyl’ chains, confirming that SdsAP is a primary alkylsulfatase.


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