Linked Life Data

8204627

Source:http://linkedlifedata.com/resource/pubmed/id/8204627

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
1994-7-8
pubmed:abstractText
The aminoglycoside phosphotransferases (APHs) are responsible for the bacterial inactivation of many clinically useful aminoglycoside antibiotics. We report the characterization of an enterococcal enzyme, APH(3')-IIIa, which inactivates a broad spectrum of aminoglycosides by ATP-dependent O-phosphorylation. Overproduction of APH(3')-IIIa has permitted the isolation of 30-40 mg of pure protein/(L of cell culture). Purified APH(3')-IIIa is a mixture of monomer and dimer which is slowly converted to dimer only over time. Dimer could be dissociated into monomer by incubation with 2-mercaptoethanol, suggesting that dimerization is mediated by formation of disulfide bond(s). Both monomer and dimer show Km values in the low micromolar range for good substrates such as kanamycin and neomycin, and kcat values of 1-4 s-1. All aminoglycosides show substrate inhibition except amikacin and kanamycin B. Determination of minimum inhibitory concentrations indicates a positive correlation between antibiotic activity and kcat/Km, but not with Km or kcat. NMR analysis of phosphorylated kanamycin A has directly demonstrated regiospecific phosphoryl transfer to the 3'-hydroxyl of the 6-aminohexose ring of the antibiotic. Analysis of structure-activity relationships with a variety of aminoglycosides has revealed that the deoxystreptamine aminocyclitol ring plays a critical role in substrate binding. This information will form the basis for future design of inhibitors of APH(3')-IIIa.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6936-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Broad spectrum aminoglycoside phosphotransferase type III from Enterococcus: overexpression, purification, and substrate specificity.
pubmed:affiliation
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't