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Interchangeable Domains in the Kdo Transferases of Escherichia coli and Haemophilus influenzae

dc.contributor.author Chung, Dr Hak Suk
dc.contributor.author Raetz, Christian RH
dc.date.accessioned 2011-06-21T17:22:09Z
dc.date.available 2011-06-21T17:22:09Z
dc.date.issued 2010
dc.identifier.citation Chung,Hak Suk;Raetz,Christian R. H.. 2010. Interchangeable Domains in the Kdo Transferases of Escherichia coli and Haemophilus influenzae. Biochemistry 49(19): 4126-4137.
dc.identifier.issn 0006-2960
dc.identifier.uri https://hdl.handle.net/10161/4009
dc.description.abstract Kdo(2)-lipid A, a conserved substructure of lipopolysaccharide, plays critical roles in Gram-negative bacterial survival and interaction with host organisms. Inhibition of Kdo biosynthesis in Escherichia coli results in cell death and accumulation of the tetra-acylated precursor lipid IVA. E. coil KdtA (EcKdtA) is a bifunctional enzyme that transfers two Kdo units from two CMP-Kdo molecules to lipid IVA. In contrast, Haemophilia influenzae KdtA (HiKdtA) transfers only one Kdo unit. E. coil CMR300, which lacks Kdo transferase because of a deletion in kdtA, can be rescued to grow in broth at 37 degrees C if multiple copies of msbA are provided in trans. MsbA, the inner membrane transporter for nascent lipopolysaccharide, prefers hexa-acylated to tetra-acylated lipid A, but with the excess MsbA present in CMR300, lipid IVA is efficiently exported to the outer membrane. CMR300 is hypersensitive to hydrophobic antibiotics and bile salts and does not grow at 42 degrees C. Expressing HiKdtA in CMR300 results in the accumulation of Kdo-lipid IVA in place of lipid IVA without suppression of its growth phenotypes at 30 degrees C. EcKdtA restores intact lipopolysaccharide, together with normal antibiotic resistance, detergent resistance, and growth at 42 degrees C. To determine which residues are important for the mono- or bifunctional character of KdtA, protein chimeras were constructed using EcKdtA and HiKdtA. These chimeras, which are catalytically active, were characterized by in vitro assays and in vivo complementation. The N-terminal half of KdtA, especially the first 30 amino acid residues, specifies whether one or two Kdo units are transferred to lipid IVA.
dc.language.iso en_US
dc.publisher AMER CHEMICAL SOC
dc.relation.isversionof 10.1021/bi100343e
dc.subject 3-deoxy-d-manno-octulosonic acid transferase
dc.subject bacterial outer-membrane
dc.subject lipid-a
dc.subject lipopolysaccharide
dc.subject biosynthesis
dc.subject gene
dc.subject purification
dc.subject expression
dc.subject phosphorylation
dc.subject cloning
dc.subject biochemistry & molecular biology
dc.title Interchangeable Domains in the Kdo Transferases of Escherichia coli and Haemophilus influenzae
dc.title.alternative
dc.type Other article
dc.description.version Version of Record
duke.date.pubdate 2010-5-18
duke.description.issue 19
duke.description.volume 49
dc.relation.journal Biochemistry
pubs.begin-page 4126
pubs.end-page 4137


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