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Identification and characterization of a 3‐deoxy‐D‐manno‐oct‐2‐ulosonic acid (Kdo) oxidase; kdoO
Author(s) -
Chung Hak Suk,
Raetz Christian R. H.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.463.4
Subject(s) - burkholderia , lipid a , chemistry , enzyme , oxidase test , bacteria , biochemistry , yersinia pestis , microbiology and biotechnology , gene , biology , genetics , virulence
Several important Gram‐negative pathogens, including strains Yersinia pestis, Burkholderia pseudomallei, and Acinetobacter, synthesize an analog of Kdo, known as Ko, in which one of the hydrogen atoms at the Kdo 3‐position is replaced with an hydroxyl group. The origin of Ko has not been explored, but studies with Burkholderia cepacia have shown that Kdo is synthesized and transferred to lipid A by KdtA, exactly as in E. coli. The function of Ko is unknown. We have recently explored the idea that Ko might be derived from Kdo by an enzymatic reaction with a mechanism similar to LpxO. Taking advantage of bioinformatics methods, we cloned and expressed potential genes from Y. pestis and B. ambifaria into E. coli WBB06. Remarkably, 50 % to 90 % of the Kdo2‐lipid A was recovered as Ko‐Kdo‐lipid A in both constructs, as judged by TLC and ESI/MS analysis. Therefore, we designated these genes as kdoO. The formation of Ko requires the presence of O2 during bacterial growth and the oxygen atom in Ko is derived from molecular oxygen. Furthermore we have overexpressed KdoO and reconstituted enzymatic activity in vitro.