Pulmonary Nocardiosis With Endobronchial Involvement Caused by Nocardiaaraoensis.

We report a rare case of pulmonary nocardiosis with endobronchial involvement caused by Nocardia araoensis. A 79-year-old man with a history of asthma and a previous right upper lobectomy for lung cancer and organizing pneumonia presented with cough and dyspnea. He presented with right bronchial stenosis associated with various mucosal lesions, including ulcerative and exophytic lesions. N araoensis was detected in sputum samples collected via bronchoscopy. The mucosal lesions improved after a 2-week course of meropenem. After a further 6 months of oral sulfamethoxazole-trimethoprim treatment, the mucosal lesions completely disappeared. Based on bronchoscopic and pathophysiologic findings, the patient was diagnosed with pulmonary nocardiosis with endobronchial involvement. Nocardiosis should be considered in the differential diagnosis of endobronchial mucosal lesions.

Identification of protein kinase CK2 inhibitors using solvent dipole ordering virtual screening.

Novel protein kinase CK2 inhibitors were identified using the solvent dipole ordering virtual screening method. A total of 26 compounds categorized in 15 distinct scaffold classes inhibited greater than 50% of enzyme activity at 50 µM, and eight exhibited IC50 values less than 10 µM. Most of the identified compounds are lead-like and dissimilar to known inhibitors. The crystal structures of two of the CK2 complexes revealed the high accuracy of the predicted binding modes.

Structure-based design of novel potent protein kinase CK2 (CK2) inhibitors with phenyl-azole scaffolds.

Protein kinase CK2 (CK2) is a ubiquitous serine/threonine protein kinase for hundreds of endogenous substrates. CK2 has been considered to be involved in many diseases, including cancers. Herein we report the discovery of a novel ATP-competitive CK2 inhibitor. Virtual screening of a compound library led to the identification of a hit 2-phenyl-1,3,4-thiadiazole compound. Subsequent structural optimization resulted in the identification of a promising 4-(thiazol-5-yl)benzoic acid derivative.

SDOVS: a solvent dipole ordering-based method for virtual screening.

We previously reported that solvent dipole ordering (SDO) at the ligand binding site of a protein indicates an outline of the preferred shape and binding pose of the ligands. We suggested that SDO-mimetic pseudo-molecules that mimic the 3D shape of the SDO region could be used as molecular queries with a shape similarity matching method in virtual screening. In this work, a virtual screening method based on SDO, named SDOVS, was proposed. This method was applied to virtual screening of ligands for four typical drug target proteins and the performance compared with that of FRED (well-known rigid docking method); the efficiency of SDOVS was demonstrated to be better than FRED.

Ligand shape emerges in solvent dipole ordering region at ligand binding site of protein.

Solvent dipole ordering (SDO), introduced by Higo et al. (Proteins Struct Funct Genet 2000, 40, 193), is an entity that captures an aspect of hydration structure. We have studied SDO in the ligand binding site of two proteins (FK506 binding protein and dihydrofolate reductase) and found that the high SDO regions overlap significantly with the 3D structures of known inhibitors bound to the proteins. Thus, the SDO region might be used to predict the preferred molecular shape of ligands that bind to a protein. Based on this finding, we propose a novel docking procedure using model molecules that mimic the shape of the SDO region. To prove the validity of thisapproach, we performed a redocking experiment for p38 mitogen-activated protein kinase ligands using model molecules for search queries; we succeeded in identifying the binding conformations and binding modes of known inhibitors.

Cluster hydration model for binding energy calculations of protein-ligand complexes.

We present a new model for predicting the binding affinity in protein-ligand complexes based on an explicit solvent treatment. The model is referred to as the cluster hydration model. Test calculations were performed on complexes of FK506-binding protein (FKBP) and its six ligands. The calculated binding energies had a good correlation with experimental binding affinities; the correlation coefficient r(2) was 0.93. Moreover, we examined the competition between the residue-ligand interactions and the desolvation energies of residues. The results suggested that, for the stabilization of the complexes in solution, the contributions of nonpolar residues at the binding site are larger than those of charged and polar ones because the electrostatic interaction energies between the residues and the ligand were mostly canceled by the desolvation penalties.