Characterization and sequence of the Chryseobacterium (Flavobacterium) meningosepticum carbapenemase: a new molecular class B beta-lactamase showing a broad substrate profile.
The metallo-beta-lactamase produced by Chryseobacterium (formerly Flavobacterium) meningosepticum, which is the flavobacterial species of greatest clinical relevance, was purified and characterized. The enzyme, named BlaB, contains a polypeptide with an apparent Mr of 26000, and has a pI of 8.5. It hydrolyses penicillins, cephalosporins (including cefoxitin), carbapenems and 6-beta-iodopenicillanate, a mechanism-based inactivator of active-site serine beta-lactamases. The enzyme was inhibited by EDTA, 1-10 phenanthroline and pyridine-2,6-dicarboxylic acid, with different inactivation parameters for each chelating agent. The C. meningosepticum blaB gene was cloned and sequenced. According to the G+C content and codon usage, the blaB gene appeared to be endogenous to the species. The BlaB enzyme showed significant sequence similarity to other class B beta-lactamases, being overall more similar to members of subclass B1, which includes the metallo-enzymes of Bacillus cereus (Bc-II) and Bacteroides fragilis (CcrA) and the IMP-1 enzyme found in various microbial species, and more distantly related to the metallo-beta-lactamases of Aeromonas spp. (CphA, CphA2 and ImiS) and of Stenotrophomonas maltophilia (L1).
Rossolini
G M
GM
Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Università di Siena, 53100-Siena, Italy. Rossolini@unisi.it
Franceschini
N
N
Riccio
M L
ML
Mercuri
P S
PS
Perilli
M
M
Galleni
M
M
Frere
J M
JM
Amicosante
G
G
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005417:Flavobacterium / Q000201:enzymology* / Q000472:pathogenicity; D008667:Metalloproteins / Q000737:chemistry; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D001618:beta-Lactamases / Q000737:chemistry*
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D008667:Metalloproteins; D001618:beta-Lactamases; C063912:carbapenemase