Crystal structure of carbapenem synthase (CarC).
The proposed biosynthetic pathway to the carbapenem antibiotics proceeds via epimerization/desaturation of a carbapenam in an unusual process catalyzed by an iron- and 2-oxoglutarate-dependent oxygenase, CarC. Crystal structures of CarC complexed with Fe(II) and 2-oxoglutarate reveal it to be hexameric (space group C2221), consistent with solution studies. CarC monomers contain a double-stranded beta-helix core that supports ligands binding a single Fe(II) to which 2-oxoglutarate complexes in a bi-dentate manner. A structure was obtained with l-N-acetylproline acting as a substrate analogue. Quantum mechanical/molecular mechanical modeling studies with stereoisomers of carbapenams and carbapenems were used to investigate substrate binding. The combined work will stimulate further mechanistic studies and aid in the engineering of carbapenem biosynthesis.
Clifton
Ian J
IJ
Oxford Centre for Molecular Sciences and The Dyson Perrins Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
Doan
Linh X
LX
Sleeman
Mark C
MC
Topf
Maya
M
Suzuki
Hikokazu
H
Wilmouth
Rupert C
RC
Schofield
Christopher J
CJ
D001665:Binding Sites; D015780:Carbapenems / Q000096:biosynthesis*; D003461:Crystallography; D007501:Iron / Q000737:chemistry; D007656:Ketoglutaric Acids / Q000737:chemistry; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D016973:Pectobacterium carotovorum / Q000201:enzymology*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
D015780:Carbapenems; D007656:Ketoglutaric Acids; D007501:Iron; D010088:Oxidoreductases; C022398:phytoene dehydrogenase