Linked Life Data

17330961

Source:http://linkedlifedata.com/resource/pubmed/id/17330961

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2007-3-20
pubmed:abstractText
Previously we have identified a highly active ribozyme (R180, cis ribozyme) that can catalyze dipeptide synthesis using N-biotinylcaproyl-aminoacyl-adenylate anhydride (Bio-aa-5'-AMP) as its substrate. In this work, we re-engineered the cis R180 ribozyme into a 158-nt trans ribozyme (TR158) and designed a new substrate (5'-Phe-linker-20-mer). First, the metal ion requirements were examined and compared between the two ribozymes. Both R180 and TR158 ribozymes were active in Mg2+ and Ca2+ but inert with Zn2+, Cu2+, Mn2+, and Co2+. It is intriguing that both ribozymes were highly active in Li+, Na+, or K+ alone but showed very low activity with NH4+. The two ribozymes showed similar linear concentration dependence on Li+ and K+, while they displayed different dependency behavior on Mg2+. Moreover, by using the trans system, the detailed kinetic studies and pH dependent experiments were performed in either 10 mM Mg2+ or 1.0 M Li+. Analysis of kcat and Km values obtained at different pHs (6.0 to 9.0) indicated that it is the catalytic activity of the ribozyme but not the substrate binding affinity that changes significantly with pH. The slopes of the linear parts of the pH-rate plots were close to 1.0 in both Mg2+- and Li+-mediated reactions, suggesting that one proton transfer is involved in the rate-limiting step of catalysis. Overall, our results suggest that Mg2+ and Li+ function similarly in the ribozyme-catalyzed dipeptide synthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
46
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3714-23
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Ribozyme-catalyzed dipeptide synthesis in monovalent metal ions alone.
pubmed:affiliation
Laboratory of RNA Chemical Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Science Park, Guangzhou, China 510663.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't