The 1.5-Å Structure of Chryseobacterium meningosepticum Zinc β-Lactamase in Complex with the Inhibitor, D-Captopril

Abstract

The crystal structure of the class-B ␤-lactamase, BlaB, from the pathogenic bacterium, Chryseobacterium meningosepticum, in complex with the inhibitor, D-captopril, has been solved at 1.5-Å resolution. The enzyme has the typical ␣␤/␤␣ metallo-␤-lactamase fold and the characteristic two metal binding sites of members of the subclass B1, in which two Zn 2؉ ions were identified. D-Captopril, a diastereoisomer of the commercial drug, captopril, acts as an inhibitor by displacing the catalytic hydroxyl ion required for antibiotic hydrolysis and intercalating its sulfhydryl group between the two Zn 2؉ ions. Interestingly, D-captopril is located on one side of the active site cleft. The x-ray structure of the complex of the closely related enzyme, IMP-1, with a mercaptocarboxylate inhibitor, which also contains a sulfhydryl group bound to the two Zn 2؉ ions, shows the ligand to be located on the opposite side of the active site cleft. A molecule generated by fusion of these two inhibitors would cover the entire cleft, suggesting an interesting approach to the design of highly specific inhibitors.

Catalytic Role of the Metal Ion in the Metallo-β-lactamase GOB

“…Based on this heterogeneity, M␤Ls have been classified into three subclasses: B1, B2, and B3 (3). Subclass B1 includes several chromosomally encoded enzymes, such as BcII from Bacillus cereus (11)(12)(13), CcrA from Bacteroides fragilis (14 -17), BlaB from Elizabethkingia meningoseptica (18), and transferable VIM (19), IMP (20,21), SPM (22), and GIM (23) type enzymes. Subclass B2 includes the CphA (24,25) and ImiS (26) lactamases from Aeromonas species and Sfh-I from Serratia fonticola (27).…”

X-ray Absorption Spectroscopy of the Zinc-Binding Sites in the Class B2 Metallo-β-lactamase ImiS from Aeromonas veronii bv. sobria

“…Considerable information exists regarding the B1 and B3 enzymes, including X-ray diffraction (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29), spectroscopic (9,(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42), mechanistic (43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59), and computational studies (60)(61)(62)(63)(64)…”

Enhancement of antibiotic-activity through complexation with metal ions - Combined ITC, NMR, enzymatic and biological studies

“…[11,12] These metallohydrolases require at least one metal ion in the active site to coordinate to the nucleophile required for hydrolysis. [7][8][9][10][13][14][15][16][17] In recent years, several groups have been…”

“…Formation of the cell wall is blocked, leading to bacterial death induced through osmotic pressure. [7][8][9][10] To prevent this destruction, bacteria have developed a variety of different resistance strategies, with mechanisms based on the degradation of the β-lactam antibiotic through hydrolysis of the lactam ring being the most dynamic approach. [9] Different types of β-lactamases have evolved to disable new generations of β-lactam antibiotics, with metallo-β-lactamases (MBLs) being one of the major causes of widespread antibacterial resistance towards the important carbapenem class of antibiotics.…”