Linked Life Data

21381755

Source:http://linkedlifedata.com/resource/pubmed/id/21381755

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2011-4-13
pubmed:abstractText
Inorganic polyphosphate (polyP) plays a number of critical roles in bacterial persistence, stress, and virulence. PolyP intracellular metabolism is regulated by the polyphosphate kinase (PPK) protein families, and inhibition of PPK activity is a potential approach to disrupting polyP-dependent processes in pathogenic organisms. Here, we biochemically characterized Mycobacterium tuberculosis (MTB) PPK2 and developed DNA-based aptamers that inhibit the enzyme's catalytic activities. MTB PPK2 catalyzed polyP-dependent phosphorylation of ADP to ATP at a rate 838 times higher than the rate of polyP synthesis. Gel filtration chromatography suggested MTB PPK2 to be an octamer. DNA aptamers were isolated against MTB PPK2. Circular dichroism revealed that aptamers grouped into two distinct classes of secondary structure; G-quadruplex and non-G-quadruplex. A selected G-quadruplex aptamer was highly selective for binding to MTB PPK2 with a dissociation constant of 870 nM as determined by isothermal titration calorimetry. The binding between MTB PPK2 and the aptamer was exothermic yet primarily driven by entropy. This G-quadruplex aptamer inhibited MTB PPK2 with an IC(50) of 40 nM and exhibited noncompetitive inhibition kinetics. Mutational mechanistic analysis revealed an aptamer G-quadruplex motif is critical for enzyme inhibition. The aptamer was also tested against Vibrio cholerae PPK2, where it showed an IC(50) of 105 nM and insignificant inhibition against more distantly related Laribacter hongkongensis PPK2.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
19
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3261-71
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Aptamer-mediated inhibition of Mycobacterium tuberculosis polyphosphate kinase 2.
pubmed:affiliation
Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't